Alert !!!!/ Toad Air Brake Tn rally

[0533]

Several of us who attended the rally in Tn. had the Air Force One Toad Air Brake system installed at the rally.

We had ours installed last Thursday and left for jacksonville the next day. Spent Friday in the Columbia area and the next two nights in Fort Clinch State park on Amelia Island Fl.

We used the HWH leveling system for the two day stay and all went well. On Monday am at 6am we started coach and could not get full air on either side and had a noise coming from the back. We were heading to Prevost for a scheduled appointment and decided to keep an eye on the gages and move along.

Once at Prevost and up on the rack we could see that the new Air Force One Tank and valve that was attached to the D/S rear drive near the bag but very close to the frame sheared of at the T fitting between the tank and the valve, the valve was just tangling from the plastic tubing.

What had happened was that the Air force one guys ( who by the way were really nice people and are going to cover the cost of my time at Prevost and wanted to find out what happened) had not anticipated just how far down a Prevost goes when it is in the leveling phase and in my case the auto leveling phase, the bottom of the coach just sheared off the fitting, it snapped like a twig.

Please take a better look at each or our installs and see that they are not too close to the frame, at the transmission arch.

Bruce

[Ray Davis]

Sounds like a really important thing to remember when having these installed, i.e. run it through a full range of motion by letting all air out, and pumping up again?

[lloyd&pamela]

I had one installed. They sent me replacement LED's since ours did not work when we left the RV park.

As a newbie I do not understand everything that Bruce described. What should I do and look for? Thanks.

[Jon Wehrenberg]

Lloyd,

The system should not use air except when applying the service brakes if I understood the explaination.

What Bruce is saying I think is that when his coach was sitting low it sheared off a fitting on the device that separates the toad air system from the coach air system.

What I do not understand is why Bruce heard air at times other than when he was applying brakes.

For your peace of mind you should do a pre trip inspection to verify everything is OK. After you hook up the Jeep, with the system completely aired up shut off the engine. Release the parking brake. The brakes should release, there should be a slight drop in the air pressure and then it should stop. The air pressure should hold where it is and there should be no sound of escaping air.

Then apply the service brakes and hold them. Again there will be a small drop in pressure as they are applied, but the drop should again stop almost immediately. Like before there should be no sound of air escaping. If you want to really be sure have Pam walk around the outside while you are doing this to listen carefully for the sound of air escaping. If she hears any you have a problem.

What Bruce said about not being able to raise the coach would strongly suggest the component in question was attached to the aux air circuit. Bruce, we need a more detailed description because the only air escaping should occur when the service brakes are applied.

[lloyd&pamela]

Thanks Jon. We are her in Gatlinburg until Sunday AM. We will check them first thing in the morning. Thank you,
Lloyd

[Jim Skiff]

I have contacted Peter at SMI Brake and expressed my concerns.
He has been given codes and will be available to address member issues.

Jim

[tdelorme]

Bruce, I'm just glad you guys made it to Prevost safely. You have better nerves than I do. I just don't think I'm brave enough to head out on the road with an air leak that I can hear. I would expect these guys to do what's right as far as covering your repair cost and hopefully learn from your experience.

Thanks again for your willingness to let Jan explore your coach, she is still raving about it. Travel well.

[Jon Wehrenberg]

Just so everyone is completely clear...your brakes systems have zero pressure on the brake chambers or lines leading to them when the emergency brake is on and the service brakes are not applied. I presume when Bruce tried to air up his coach and raise it to the ride height he had the brake on and his foot was not on the brake pedal.

Air pressure to the emergency brake side of the brake actuator RELEASES the brakes which are held in place when parked by a huge spring.

The service brake side of the system has no pressure whatsoever unless and until you step on the brake pedal.

For a system that is supposedly connected to the brakes to be releasing air constantly something is wrong. Especially when the leak is large enough to prevent the air suspension system from pressurizing sufficiently to raise the coach.

I think this is important enough for anyone who had this installation to verify the components that were installed were connected to the correct part of the air system.

[Ray Davis]

In thinking about what Jon said, I went to the SMI site to see if I could find ain installation guide.

I wasn't successful in that, but I did find a "plumbing" diagram.

It's not 100% clear, but it looks like they expect to tap into an air supply system AND then also to the brake.

I believe they show this on this diagram

http://www.smibrake.com/GetProductImage.aspx?ID=4

as "supply-air connection", and "metered-air connection".

I assume metered would be the brake lines, but I will admit to guessing here.


Ray

[Joe Cannarozzi]

"After you hook up the Jeep, with the system completely aired up shut off the engine. Release the parking brake. The brakes should release, there should be a slight drop in the air pressure and then it should stop. The air pressure should hold where it is and there should be no sound of escaping air.

Then apply the service brakes and hold them. Again there will be a small drop in pressure as they are applied, but the drop should again stop almost immediately. Like before there should be no sound of air escaping."

What Jon has described here is critical and is worth repeating even if only 1 more member soaks it in.

This is a standard pre-trip inspection that should happen EVERY time you head out. It only takes 2 minutes. This is also the way we isolate a problem and helps pinpoint what.

Adding to this would be to air up and shut the bus off before you release the brakes, if there is a evident air leak at this point it would/could probably be in a suspension component. An air bag or a line to them or a ride height valve or norgren valve or possibly less common, a tank or tank fitting.

If all good, next, when the parking brake is released but before service brakes applied you shut the bus off and you encounter a leak that would be "emergency air" leaking, either a maxi chamber or an air line leading to them or possibly a valve.

If again all good then with the emergency brake off and the brake pedal applied and you shut the bus off and you hear a leak that would be "service air", possibly a brake diaphragm, (also incorporated into the maxi) or a line leading to that.

The maxi (brake chamber) has 2 air lines going to them. 1 is emergency air that airs up (by pushing the parking brake button) the side of the diaphragm opposite the large spring, just neutralizing (not overwhelming), the large parking brake spring thus releasing the parking brake.

For all you scuba divers think of it as when you release the parking brake your creating neutral buoyancy within the chamber by putting emergency air to the opposite side of the diaphram as the spring.

The other air line is service air and it is introduced (by stepping on the brake pedal) to the side of the diaphragm WITH the spring and that service air combined with the force of that spring DOES OVERWHELM that emergency air on the other side of the diaphragm thus engaging the brakes and with as little as or as much air as is introduced depending on how hard you apply pressure on the brake pedal.

[0533]

Good morning All,

I have been traveling and am just now getting back online to look at these posts.

Here is what we found with the "Air Force One Air Brake" system. They mounted the Air tank, small version of the Prevost tanks and a valve near the D/S rear tag wheel up under the frame attached near the U shaped tunnel for the drivetrain shaft. When the Prevost leveling system was air was dumped the fitting between the Air Force One valve and the Air Force one tank caught on the corner of the Prevost frame and snapped of the valve at the fitting to the tank. The noise that I heard was the air in the tank evacuating. What I could not understand is why my main air was acting squirrely, not running up and dropping off quickly. I ended up having to replace my dryer in this process as it would not blow off at full pressure after this event. It might not be related but it was odd. The bottomline here is that the Prevost equipment and placement has been engineered carefully and with all of the potential pitfalls in mind. I am afraid that this is not the case with others, as there is not enough experience with our heavy complex units. Mine ran great out of jacksonville to San Antonio Fl. but I have to say that there is a large ????? mark in the back of my mind about the future, rocks, whatever. Hope I am wrong and am sure that the folks at Air Force One will be carefully looking into this and will report back to us online to give us a first hand assessment.

[phorner]

This is bad news, as I think that you have to assume that ALL installations performed at the rally were done in the same manner. What would be the rationale to doing it differently on individual busses?

It seems to me that everyone that had the Air Force One installed at the rally should have their installation inspected as soon as possible to determine what needs to be rectified.

[lloyd&pamela]

Bruce did you have the Aif Force One tank relocated at Prevost? What was your fix?

[lloyd&pamela]

We did the tests this morning that Jon and Joe mentioned and do not hear any air leaking.

I contacted Pete at SMI and we are going to have John Bleakely in Atlanta (one of there Tier 1 dealers) look at the bus while they are doing some other work next week.

I feel better now, but will feel even more secure after they lift it up and check underneath.

Thank you Bruce for the heads up and then you Jon and Joe for the trouble shooting. We now have a new addition to the checklist.

[0533]

We did the tests this morning that Jon and Joe mentioned and do not hear any air leaking.

I contacted Pete at SMI and we are going to have John Bleakely in Atlanta (one of there Tier 1 dealers) look at the bus while they are doing some other work next week.

I feel better now, but will feel even more secure after they lift it up and check underneath.

Thank you Bruce for the heads up and then you Jon and Joe for the trouble shooting. We now have a new addition to the checklist.
I would recommend that you and Pam get up at 5am each morning and go over the checklist for departure. It might be nice to have it on your PDA while you do your preflight. Check the landing gear, all wheel wells for illegal aliens etc.

I frankly would not be concerned enough to make it part of a check list, but rather remember if you hear a new hissing noise in the back of the coach, you might want to check this.

PS> You mentioned the LED lights. I cannot see mine to tell if they work or not as they were placed too close to the back of the coach for the camera to see. I will move them and see if mine work.

Bruce

[smibrake]

Members of the POG forum:

We would firstly like to thank Mr. Skiff and all of the attendees of the Sevierville, TN Rally for your overwhelming support and hospitality throughout the event. As many of you know, we were able to install seven of the Air Force One systems in the time we were there. Unfortunately, Mr. Harris's coach developed an air leak sometime after the installation described in the above posts. While it wasn't possible to have a first hand look, we were able to "borrow" the eyes of the qualified technicians at Prevost in Jacksonville, FL. Although this situation is unfortunate and most untimely, we feel it as an opportunity to demonstrate our high level of customer service and our dedication to our customers' complete satisfaction.

Based on the information given by Prevost, if any of the other coaches were apt to experience such an event, it would have already occurred after moving and/or dumping the air of the coach. This leads us to believe that any other issues would have already arisen; however, to ensure complete confidence by our customers, we will be contacting all of the members who purchased Air Force One's at the show and will be providing them with option of an inspection (using the information provided by Prevost) at our nearest qualified installation center.

Again, we want to thank all the POG members for the incredible hospitality and acceptance. We sincerely apologize for the inconvenience we caused Bruce and will do everything possible to boost his confidence in Air Force One and SMI. We look forward to seeing you all soon.

Sincerely,

Peter F. Schuck, II
President

Toll free - 800-893-3763
Cell - 812-483-3507
Email- Pete@smibrake.com

[Jon Wehrenberg]

Peter,

You explained during the seminar that the system which includes an assembly installed on the bus, and a veturi type assembly which is installed on the toad is connected to the bus braking system, and as such uses no air unless service brakes are applied.

Please help us understand how a broken fitting could cause ANY air to be heard, and / or how the bus would have trouble airing up due to a broken fitting.

We can remove the air hoses for our service brakes and never have any air escape until those brakes were applied. I am interested in the set up for my toad, and I would like to know exactly what happened (apart from a broken fitting).

[0533]

Peter,

You explained during the seminar that the system which includes an assembly installed on the bus, and a veturi type assembly which is installed on the toad is connected to the bus braking system, and as such uses no air unless service brakes are applied.

Please help us understand how a broken fitting could cause ANY air to be heard, and / or how the bus would have trouble airing up due to a broken fitting.

We can remove the air hoses for our service brakes and never have any air escape until those brakes were applied. I am interested in the set up for my toad, and I would like to know exactly what happened (apart from a broken fitting).
Good morning Jon,

I may be able to shed some light on this question. The system may in fact be isolated from the rest of the coach, but at the moment I brought the coach back up to the ride height when getting ready to leave the campground is when we think we sheered off the fitting. The black plastic lines that came from the valve to the rear connection to the toad ran in two different locations. One black plastic air line was routed under the drive shaft and one was on top of the shaft, both found their way to the valve that was attached to the small tank. I think the noise I heard was the air being drawn out of the small tank when the fitting was torn off. What I cannot explain is the difficulty getting up to full air and when I used the brakes the air would drop quickly to about 95lbs and have a hard time getting back to 125/130 range (hovereing around 105), and they fluctuated at times, one gage higher or lower than the other. Here is the odd part, and maybe its a green banana. During the Prevost service process they could not make the dryer blow off at full pressure, when it was working fine before. More questions than answers I guess.

I was pleased to see that Peter has taken the time to share his thoughts with us, and wants to make certain that all of our installs are done correctly. It is also gratifying that Peter has contacted the folks at Jacksonville Prevost to get a handle on what went wrong and how to prevent the problem in the future.

A couple of thoughts come to mind when thinking about what Prevost found and what steps were taken. The problem was found on the evening shift by one of their best techs, "Jasen" who is a outstanding tech, a detail nut and is extremely talented found the exact location and made the fix. He did not exactly reengineer the system, just rerouted the black airlines and placed the unit in a slightly different location after he tapped out the broken fitting and put the valve back together with the tank. It was not rocket science, just common sense and the advantage of being five feet in the air looking directly at the problem.

After this experience I decided to take a better look at my toad to check the install here a little better. First thing that I have noticed is that when I start the vehicle now (2008 Saturn Vue) I no longer need to place my foot on the brake before turning the key on. I can easily get used to this new feature but have to wonder how Saturn will feel about the modification to a federally mandated requirement. Also in my engine compartment is the controller, it is hanging down at a 45 degree angle attached to a bunch of wires next to the engine block, very close to other wires that if ever need to be serviced will surely be in the way. And finally my plastic air cleaner was not reattached, was loose inside the engine compartment. I do not want to place blame on anyone here, in fact I really like the father and son team who did the install, great people. I think the problem is two fold. 1. These rallies are time limited and to make the numbers work and to satisfy the customers who want the product now, not later these guys must work from 8am to 8pm to make it happen, and this can create install issues. 2. This may be the most important issue. Engineering. It is difficult for a company like "Air Force One" to have been able to spend the time and money to do the necessary engineering that would be required to be able to make these installs in different coaches and different vehicle types. My saturn Vue is brand new and has been redesigned with very small spaces, lots of engine packed in there.

I think that a better plan would include some more detailed engineering in advance. This would of course drive up the cost and delay the release, it is always a push pull in the real world.

[Jon Wehrenberg]

Bruce,

I am not trying to give Peter a hard time, nor am I criticizing the product. What I am trying to do however is to get a full understanding of why you had the air system problems you describe relative to a broken fitting on a device that should never see air flow unless and until you apply the service brakes.

The loss of brake system air pressure as you describe was both predictable and understandible and was consistent with the damaged fitting. What I am still trying to grasp is how this could possibly contribute to the other issues you describe. You literally have a braking system that is not ever going to leak air unless you apply the brakes, yet now your dryer will not "spit" and you are having troubles getting up to pressure. I can't put the two together.

Anybody else out there have any ideas? I think the braking system is great, but before I contemplate installing one on the Hummer with round tires I would like to know more.

Relative to the install, I would want to do my own. It will just take time, but as I understood the system it is fairly simple.

[0533]

Bruce,

I am not trying to give Peter a hard time, nor am I criticizing the product. What I am trying to do however is to get a full understanding of why you had the air system problems you describe relative to a broken fitting on a device that should never see air flow unless and until you apply the service brakes.

The loss of brake system air pressure as you describe was both predictable and understandible and was consistent with the damaged fitting. What I am still trying to grasp is how this could possibly contribute to the other issues you describe. You literally have a braking system that is not ever going to leak air unless you apply the brakes, yet now your dryer will not "spit" and you are having troubles getting up to pressure. I can't put the two together.

Anybody else out there have any ideas? I think the braking system is great, but before I contemplate installing one on the Hummer with round tires I would like to know more.

Relative to the install, I would want to do my own. It will just take time, but as I understood the system it is fairly simple.
The fitting that snapped off and the air dryer may not be related but merely a coincidence.

The fitting between the valve and the tank snapped off and left an opening in the tank and the valve. The valve still had both black air lines attached going to the back of the coach and I believe to the bus air. The Air Force One small tank was connected to the Prevost.

Is it possible that when I applied the brakes on the coach that some air was being bleed directly into the small (AF0) tank/valve??? that was open to the outside air???? Also I do not know where the two black air lines went to and came from to be honest, put thought that one was coming from the main bus air and one was going to the toad, and possibly the valve kept the pressure up using the small tank as a source of air. Question. Both the valve and the tank were affected by the snapped fitting, which one came from the bus air system? As you know I am not nearly as knowledgable as you or most POG members, this is all from visual memory.

[Jon Wehrenberg]

This is a place for Peter to jump in and help. It is my understanding the assembly that attaches to your bus receives air pressure only when the service brakes are supplied. Its purpose is to function as a pass through device when everything is working perfectly. When the toad breaks away however, it will break the air line from the bus to the toad so the bus mounted device functions like a propane tank valve and shuts off air flow when it senses the line to the toad is now broken. That preserves the bus braking system and is a safety device.

I am presuming your broken fitting was between this device and the bus braking system.

The device on the toad serves to create vacuum via pressure venturi and it is that vacuum that keeps your power brake booster in a negative pressure condition to provide power assist when the brakes are applied. Additionally that device has a small internal air pressure storage tank to apply the toad brakes in the even of a breakaway. When the toad is connected to the bus and all is operating normally, your air brake pressure on the bus is also supplied to the toad to operate the toad brake pedal via the small air cylinder attached to the brake pedal.

If the system, as I described it is correctly installed it is unrelated to the bus air system pressures and it may be just a coincidence you are experiencing problems reaching normal pressure. At the pressures you describe you will not even be able to lift the front of your bus, and the rear will be marginal.

[0533]

This is a place for Peter to jump in and help. It is my understanding the assembly that attaches to your bus receives air pressure only when the service brakes are supplied. Its purpose is to function as a pass through device when everything is working perfectly. When the toad breaks away however, it will break the air line from the bus to the toad so the bus mounted device functions like a propane tank valve and shuts off air flow when it senses the line to the toad is now broken. That preserves the bus braking system and is a safety device.

I am presuming your broken fitting was between this device and the bus braking system.

The device on the toad serves to create vacuum via pressure venturi and it is that vacuum that keeps your power brake booster in a negative pressure condition to provide power assist when the brakes are applied. Additionally that device has a small internal air pressure storage tank to apply the toad brakes in the even of a breakaway. When the toad is connected to the bus and all is operating normally, your air brake pressure on the bus is also supplied to the toad to operate the toad brake pedal via the small air cylinder attached to the brake pedal.

If the system, as I described it is correctly installed it is unrelated to the bus air system pressures and it may be just a coincidence you are experiencing problems reaching normal pressure. At the pressures you describe you will not even be able to lift the front of your bus, and the rear will be marginal.
I agree that its time for Peter to get in and help. To answer your second question about the place where the fitting broke, it broke at the (AFO) valve and the (AFO) tank, not the bus tank. I cannot speak to the rest, but it all sounds right.

[Jerry Winchester]

Jon,

I also don't understand where the air could come from unless the brakes were activated. The system they installed for us worked perfectly during the 1600+ miles we have driven since it was installed.

I can also say the LEDs show up well mounted on the hitch and in direct sunlight they are visible, but not like they are at other times.

I'll inspect my installation next trip out to the hanger.

JDUB

[smibrake]

Jon, Bruce and others,

Let me first address the air assembly on the coaches. The AFO keeps the coach within the FMVSS #121 regulation because of the addition of the air tank and relay valve assembly which are added during the installation. Bruce was able to hear air while the engine was running and his foot was NOT on the brake because the relay valve was no longer attached. Air Force One uses the "metered air" to determine how much "tank" air to release to the brake system. The bus brake system operates the same way. The treadle (brake pedal) meters air to the relay valve assemly, which in turn opens and closes the relay valve that uses tank air to apply the coach brakes. The flow protection valve on the other side of the AFO tank kept him from losing all the air, that is why we add it. There was an open flow on the output side of the tank because the relay valve was apparently hit by part of the "bus box" when the bus was dropped all the way. The flow protection valve kept him from losing all the air which is why it was perfectly safe to drive the coach. It was noisy, but still perfectly safe. While it is very unfortunate, it does demonstrate the "engineered in" safety of the Air Force One. If, for example, an air brake system that simply tapped into the air lines to the coach brakes had an open flow, the coach brakes would not function properly. Using our approach, even in a catastrophic event such as this, the bus brakes operated normally. Although the air was low and fluctuated, it stayed within operating range the entire time he was driving.

Now for the engineering of AFO. Brent and I created Air Force One almost 4 years ago. The original design was tested for over 9 months with 20 coaches. We used the feed back from the installers and the testing to create the product you have. At this time there are hundreds of installations done each month all over the country. To date, there has not been one car nor one coach in which we were unable to install the AFO product. We also have three rally teams and over 900 dealers. There are literally thousands of AFO's on the market and most of them are installed with wire ties under the hood. Bruce is correct, his is tied to wires, as is often the case. The use of wire ties makes it easier to service the car if it becomes necessary. In Lloyd's case the unit is screwed to a flat plate in his Jeep. In Will's case, I believe the unit is wire tied to an area near the master cylinder. The point is, no two makes of cars are the same and each install is handled accordingly. The plastic cover that Bruce is talking about should not be loose. From memory the unit is not touching the cover and this should not be causing a problem. There are three posts (two in the back and one on the driver’s side) that the cover snaps into. The oil cap holds the cover in place on the passenger side. While every effort was made to ensure the cover was replaced properly, it is possible that I missed a post or did not push it down completely. In any case, I do not think it should be a problem to snap it down.

As for the Vue and the other problems, they should not be related to the AFO. This sounds like a situation related to the brake switch or the circuitry related to it. However, anything is possible. With Bruce’s car, the brake switch does not operate when the key is not completely on. In this case we must use a pressure switch to control the LED lights. Since we used a pressure switch, we did not attach anything to his brake switch.

I also want you all to understand that as a rally team, we have installed over 250 systems at rallies since 1/1/2008. It is true that the hours are long, but we are completely accustomed to the work and that is no excuse for not doing a job right. We take pride in our work and our products and we are very focused on customer satisfaction. The problem Bruce had could have happened any time and was related to the placement of the tank assembly under the coach.

I want to offer each of you that had an install the opportunity to have your system inspected by one of our Tier One or Tier Two Dealers. All you need to do is call me and I will see who is closest to each of you. We do not have 100% coverage with this level of dealer, but we will do what we can.

I think it is also important to understand that if there were a problem with any of the other installs, it would have shown up by now. I hope that this helps you understand the installation and operation of the Air Force One brake system. Please post more questions and I will be glad to address them.

Peter Schuck
President

[Jon Wehrenberg]

Peter, Thank you. Can you post an accurate systems schematic, detailed sufficiently to illustrate your explaination? I may have misunderstood your explaination at the rally and was of the opinion you were taking air that goes to the brake chambers for the system, but it sounds like you are using metered air from the foot treadle instead. Is this correct?

I am still trying to get my arms around why he had air flow with no brake application. Any sound of escaping air is a signal to me to stop driving, and I am presuming the bus air compressor is operating 100% of this time.

[0533]

Peter, Thank you. Can you post an accurate systems schematic, detailed sufficiently to illustrate your explaination? I may have misunderstood your explaination at the rally and was of the opinion you were taking air that goes to the brake chambers for the system, but it sounds like you are using metered air from the foot treadle instead. Is this correct?

I am still trying to get my arms around why he had air flow with no brake application. Any sound of escaping air is a signal to me to stop driving, and I am presuming the bus air compressor is operating 100% of this time.
Hi Jon,

Peter did a very good job explaining how his system works. Its gratifying to have the owner step up and offer his input and stand behind the product. In no way am I saying his product does not work, or should not be considered by other POG members, it is simply a matter of my field experience and a hope to create a dialogue with POG members and Peter in an effort to make a better mouse trap.

Jon brings up a point about the continuously escaping air while I was driving from Amelia Island to Jacksonville Prevost. I monitored both the main and backup air systems for the entire 50 mile trip and they fluctuated back and forth by about 5 to 20 lbs from normal, (Normal for me is 100-133) (abnormal 85-105) both sides. I do wonder though if air was bleeding off the entire ride could this have had any affect on the failure of my Air Dryer??? The problem in this is when the Air bags were changed out at Prevost, they really give the air sytem a workout pumping them up, deflatting them many times checking for leaks etc, placing some extra stress on the Air Dryer, but in the end it would not blow off and the pressure was above 145, at least the bags didn't leak.

There was also one other minor, very minor damage when the valve was sheered off, and I should have done something about it at Prevost. When the valve dropped down around the drive shaft with the black Air Lines attached one line rubbed up against the shaft for the 50 mile ride, and was left with a small groove in the plastic. I will have to change this line when I have the time for safely purposes.

The bottom line is that I am happy to get rid of the big BLUE OX and just plug and play. One additional thought for Peter: When one takes off the tow bar assembly to stow it away it would be nice to get 2 extra plastic caps for the air lines to keep them from the Wx, dirt and dust extra.

Thanks Peter for introducing us to your creative ideas and for standing behind your products. Now I bet you wished that you had brought your fishing pole.

Bruce

[smibrake]

Bruce,

Thank you for being so understanding and patient.

It is safe to assume that the air pump was running often. Probably not continous but very often. I rebuilt my air dryer the part of the year and was amazed at how it works. The biggest villian is this white milky sludge that is caused by a mixture of air/water/oil. The pop off can get "stuck" because of the build up. In Bruces case, his pop off was stuck closed. In my case it would stick partially open. The air pump is a mechinical pump that is virtually impossible to wear out. I would imagine that if you looked at that air dryer in Bruces bus you would have found the sludge, it is just a natural by-product of drying air.

I will try to locate a .pdf of the "plumbing" for hte AFO and post it this afternoon. Basically, the AFO tank is "spliced" into one the feed lines to the bus air tanks with the flow protection valve on the input side of the tank. The treadle air is spliced in the 3/8 air line that goes between the quick release valve (e-brake) and the service brake relay assembly.

Here is how it works:

When you park the air is removed from the chambers which allows the spring to fully apply the brake (i.e. park brake). When you release the brake, air is allowed into the chambers which pushes the spring off. When you apply the treadle, air must be removed from the spring brake side of the chamber while at the same time being allowed into the service brake side. This is rather difficult to picture in your mind but a fairly simple process.

To be as safe as possible using the air on the bus, we tap in after the bus service air but before the e-brake air, if that makes sense. This is metered air but the service brakes have already used it so brake timing from front to rear is not changed more than one or two pounds. If we simply grabbed the air from the service relay as many do, brake timing from front to rear would be changed drastically. Brake timing is the time that passes between the front brakes coming on and the rear. If the timing is changed too much abnormal wear can occur on the fronts since the rears are delayed by a lack of air.

By adding the AFO tank and relay assembly, brake timing is preserved and catastrophic events are avoided.

I hope this helps you understand the system. I will look for the .pfd after church.

Pete

[Jon Wehrenberg]

"To be as safe as possible using the air on the bus, we tap in after the bus service air but before the e-brake air, if that makes sense."

No it does not make sense. But that doesn't mean you are incorrect, it just means I still haven't grasped it. I always treated the air supply to the emergency brakes which is "on" while in motion as a totally separate system from service brake air.

I would have guessed you would tap in at the relay valve to the tag axle. I am still unclear how the minimal air flow to your system would have a measurable impact on the timing between the front and rear.

[smibrake]

When you are driving the quick release valve is turned off. This is controlled by the e-brake button in the coach. The quick release valve operates much like the service relay valves but in reverse. The air that comes from the front of the bus does not apply the brakes nor is used set the e-brake. The air from the front simply controls (meters) the air from the tanks. If you tap into the air at the service relay or at the air cans then more air must be sent from the treadle before the relay "cracks" the air from the tank to apply actually apply the brakes.

Brake timing is the time that passes before the rear brakes engage after the fronts. Fronts brakes do a higher percentage of braking in all vehicles. If the timing is tampered with then premature brake wear will occur on the front brakes. According to the engineering department at Bendix, tapping into the air at the service relay will cause the crack pressure to increase by several PSI. If the standard crack pressure 8 - 10 psi and you take the air from the service brake for a tow brake system then the crack pressure will increase up to 15 - 17 psi. It does not effect the brake effort supplied at the wheels, only the timing of when they apply.

With the e-brake off air enters the system and pushes the spring which releases the brakes. In order for the treadle to operate the brakes it must work in conjunction with the spring brake valve. Metered air is sent the main relay assembly to put air on the "non-spring" side of the brakes. In order for the brakes to apply air must be removed from the spring brake side. The two systems work together. It is true that AFO uses the metered air that goes to the spring brake side but according Mike Oneal at Spartan and engineers at Bendix, this will only slightly impact the timing of the front and rear brakes. Because the metered air first goes to the main relay assembly and cracks the valve, no air is lost to this part of the system. The metered air is used in the main relay assembly and then passed to the spring brake. The AFO is tapped into the 3/8 line that connects the main relay assembly and the spring brake assembly.

It is true that air could be taken from the tag brakes and not impact timing. However, depending on the year and the make, tag brakes are typically set up to brake 20% - 40% less than the drive axle. Again, it is certainly something that is done but I do not know of a tow brake system that is designed to use tag air. The end result would be a tow brake that did not function as it should Because the air pressure was lower than it is engineered to receive.

The service relay valve is very similar to the AFO relay valve. Tank air comes into the valve and is metered by the treadle air. When Bruce lost his relay valve it did not impact the timing any more or less than if the valve had remained attached. However, since it was not attached to the AFO tank, the tank air was compromised. The air pump on the bus is capable of keeping it up to drive it in, that is a DOT regulation. The flow protection valve on the tank protected the air so it did not bleed out. Again, this safety is engineered into the AFO on purpose. Up to this event, we have never had any feed back about the function og the flow protection valve. Now we know it works and protects the coach as necessary.

I have heard for a few of the others and all say that the system works great. Will tows that 2500 Hemi Ram and feels that he stops substantially easier with the AFO. He said that in normal stopping the brake does not apply. As he stops just slightly harder than normal, the AFO applies the brakes in the truck.

I tried to simplify the operation of air brakes. It is difficult to understand and even harder to explain. Bendix has some great information available on air brakes. I will get Brent to look for a link to their site and post it Monday if he can find one.

Pete

[Jon Wehrenberg]

Thank you.

Now explain the escaping air sound when the brakes were not being applied.

From the treadle the air flow, when the treadle is operated goes to the relay valve and then to the respective brakes. There is no air flow in the system until and unless the treadle is operated. Or am I mistaken?

Also, just out of curiosity, if you prefer to not use the tag axle, what about front axle air to the service brakes?

[Orren Zook]

Thank you.

Now explain the escaping air sound when the brakes were not being applied.

From the treadle the air flow, when the treadle is operated goes to the relay valve and then to the respective brakes. There is no air flow in the system until and unless the treadle is operated. Or am I mistaken?

You are correct Jon, air from the foot valve goes to the service port of the relay valve which causes application of tank pressure via the delivery port to the spring brake assembly. There is no air to the service side of the brake chamber if the pedal is not depressed - then it is applied in a corresponding amount with the distance pedal of travel.

[smibrake]

Here is a picture of how the AFO integrates with the coach.

[smibrake]

The air going back to the towed vehicle is NOT the air from the Prevost brakes. The air from the Prevost brakes controls how much air is past from the "New Air Reserve Tank" to the "Towed Vehicle" in the above diagram. If the area between the "New Air Reserve Tank" and the "New Relay Valve" is compromised, air will be able to escape from the coach's reserve tank. That is where the "New Pressure Protection Valve" comes in. When the pressure drops in the "Existing Primary Air Reserve" to ~80-90 psi., the "New Pressure Protection Valve" closes, allowing the breach to be contained, and the coach's brakes to operate safely. Since the air pressure in the "Existing Primary Air Reserve" is lower than where the coach wants it, the compressor builds more air. Any air above the pressure protection valve's minimum limit is allowed through (to atmosphere in this case). This is where the sound of "air" would be coming from, and why the coach was still able to operate safely.

[Jon Wehrenberg]

As long as a system leakage or failure is downstream from the new pressure protection valve life is good. If it is between the valve and the supply from the primary air reservoir life sucks. A critical portion of the installation would be to provide maximum protection for the Tee and the protection valve.

Thanks for the response. It makes sense now and what you have created is a miniature air brake system that functions exactly like the bus system.

[0533]

As long as a system leakage or failure is downstream from the new pressure protection valve life is good. If it is between the valve and the supply from the primary air reservoir life sucks. A critical portion of the installation would be to provide maximum protection for the Tee and the protection valve.

Thanks for the response. It makes sense now and what you have created is a miniature air brake system that functions exactly like the bus system.
Hi Jon and Pete,

I forgot to ask one question about my Toad Brake failure. When the (AFO) valve broke away from the (AFO) tank, what if anything should of happened to the brake system on the Toad? I did not notice anything, felt no braking action saw no lights go on, and assumed now that the failure simply disables the Toad brake?

[smibrake]

As long as a system leakage or failure is downstream from the new pressure protection valve life is good. If it is between the valve and the supply from the primary air reservoir life sucks. A critical portion of the installation would be to provide maximum protection for the Tee and the protection valve.

Thanks for the response. It makes sense now and what you have created is a miniature air brake system that functions exactly like the bus system.

You got it. I might also add the bus has pressure protection valves littered throughout to isolate components in the event of a coach-related failure.

[Jon Wehrenberg]

I'm a little slow sometimes. But now that I get it I appreciate it more.

Good job.

[smibrake]

Hi Jon and Pete,

I forgot to ask one question about my Toad Brake failure. When the (AFO) valve broke away from the (AFO) tank, what if anything should of happened to the brake system on the Toad? I did not notice anything, felt no braking action saw no lights go on, and assumed now that the failure simply disables the Toad brake?

What happened in your case was the "Signal Air For New Relay Valve" was still "telling" the the valve to allow x psi to the towed vehicle; however, there was no air available to go back to the towed because the supply was severed. The end result was no braking effort.

[Ray Davis]

Pete,

I was following this discussion with interest. Being from the far coast I wasn't able to make it to the rally in TN. I hope that you will be at a future POG rally, as I'd like to get a system on my coach as well.

I appreciate how much time you have spent here, answering questions, and supporting our group.

I hope we'll get the chance to do business here in the future!


Ray

[lloyd&pamela]

Pete made arrangements for our brake system to be examined by John Bleakely in Atlanta and they said everything was fine. They also replaced the LEDs on the Toad and they work fine now.

Thanks Pete, great job and great service. We can recommend SMI highly. They have all be quite responsive.

[phorner]

Thanks, Pete for standing behind your product and providing the membership here with such a thorough and complete discussion regarding the installation process and the operation of AFO.

Having followed this discussion, I now have considerably more confidence in the system installed for us at the rally.

Anyone can look good when everything goes right (which rarely happens with anything mechanical) but, in my opinion, it's how someone reacts when a problem occurs that separates the best from the rest.

Again, thanks for being so responsive to our concerns.

[0533]

I left out of Gainesville Fl. yesterday morning for the short ride back to Jupiter. The ride went smoothly (30 mph wind gusts). As we left 95 for the ramp into Jupiter I noticed a loud howling or squealing sound coming from the back of the bus. Nothing on the gauges showed me exactly what was going on but I knew it was not necessarily good.

I decided to get off the road and limp into my slip near home a few miles away.

The noise was deafening now and when I came to a stop next to my slip I noticed that both brake gauges were now at 80lbs. but holding there. I looked under the to see the same old line and valve hanging down next to the drive shaft air streaming out of the open end, plus the valve stem had been severed off at the threaded end.

I can not understand why this has happened again, there does not to appear to be a good reason for the failure twice in the same location.

I am not certain how to make temporary repairs at this time. want to stop the leak detach the lines to the Toad Brake valve and seal the main/Air force One Air tank leak so that my main brake air tank is not continually drained down by the demand on the open valve port on the Air Force One tank.

If my attachment has been uploaded you will see where the problem is.

I want to get under the bus to examine this better, plan on tilting the airbags over to one side, placing the Prevost Jack on the high side for safety and then detach the dangling valve, and try and screw into the Airforce One Air tank some type of threaded screw to seal the hole, any ideas.

[0533]

I left out of Gainesville Fl. yesterday morning for the short ride back to Jupiter. The ride went smoothly (30 mph wind gusts). As we left 95 for the ramp into Jupiter I noticed a loud howling or squealing sound coming from the back of the bus. Nothing on the gauges showed me exactly what was going on but I knew it was not necessarily good.

I decided to get off the road and limp into my slip near home a few miles away.

The noise was deafening now and when I came to a stop next to my slip I noticed that both brake gauges were now at 80lbs. but holding there. I looked under the to see the same old line and valve hanging down next to the drive shaft air streaming out of the open end, plus the valve stem had been severed off at the threaded end.

I can not understand why this has happened again, there does not to appear to be a good reason for the failure twice in the same location.

I am not certain how to make temporary repairs at this time. want to stop the leak detach the lines to the Toad Brake valve and seal the main/Air force One Air tank leak so that my main brake air tank is not continually drained down by the demand on the open valve port on the Air Force One tank.

If my attachment has been uploaded you will see where the problem is.

I want to get under the bus to examine this better, plan on tilting the airbags over to one side, placing the Prevost Jack on the high side for safety and then detach the dangling valve, and try and screw into the Airforce One Air tank some type of threaded screw to seal the hole, any ideas.

I appear to be having problems attaching the pics for better assessment. I will continue to try.

[JIM CHALOUPKA]

Bruce, not sure how many lines you have to cap off, but for the short term if you can get to them use vise grip pliers to crimp the end to get you to somewhere where you want to do the permanent fix.
Sometimes you have to bend the line over and hold it there.
If you carry ss lock wire and you have more leaks than pliers, fold over the line and secure it with lock wire, and wrap with tape. A tiny leak will probably be tolerable.
Good luck and keep us posted :rolleyes:
JIM

[0533]

Bruce, not sure how many lines you have to cap off, but for the short term if you can get to them use vise grip pliers to crimp the end to get you to somewhere where you want to do the permanent fix.
Sometimes you have to bend the line over and hold it there.
If you carry ss lock wire and you have more leaks than pliers, fold over the line and secure it with lock wire, and wrap with tape. A tiny leak will probably be tolerable.
Good luck and keep us posted :rolleyes:
JIM
Thanks Jim,

I will try this as a short term fix. I plan on heading up to Prevost for some other regular service and this might make it easier than trying to go all the way with a complete fix as I really need to get a handle on why this has happened twice now, and how to find a way to make sure it will not reoccur.

I wanted to attach a few pics that might offer some insight, but each time I try and upload an image file Gif 570KB the POG. server will not respond, both in Safari and in Firefox, wonder if others are having this problem??

[Jon Wehrenberg]

Bruce,

Don't worry about pictures for us until you and the coach get to safety.

I will assume these problems with the braking system are isolated, but for anybody that has one of these systems I would strongly urge before you travel with your coach to add a 90 degree shutoff valve (ball valve) in the supply line to the braking system air supplies. Then no matter if you get a broken fitting or a defect in the device all you need to do is get access to the valve and shut it off. Then you can deal with the leak on your own terms.

Think of the valve the same way you would a circuit breaker. It is just there in case you have to shut down the system for service.

[Alek&Lucia]

Bruce,

Try to save your photos as JPEG it should work better.

Alek

[0533]

Bruce,

Don't worry about pictures for us until you and the coach get to safety.

I will assume these problems with the braking system are isolated, but for anybody that has one of these systems I would strongly urge before you travel with your coach to add a 90 degree shutoff valve (ball valve) in the supply line to the braking system air supplies. Then no matter if you get a broken fitting or a defect in the device all you need to do is get access to the valve and shut it off. Then you can deal with the leak on your own terms.

Think of the valve the same way you would a circuit breaker. It is just there in case you have to shut down the system for service.
Good idea Jon.

I am confused why this is happening. The last time the valve was pinched by the top of the drivetrain well when I was using my auto leveling.

This time I was simply driving along and it gave way.

I am not pleased with the experience and need to find a better way to have this entire system installed as I believe it will happen again.

It appears when they tap the air off of the main system there is no fail safe built in to protect the braking system in the event of a failure.

[Orren Zook]

Your picture shows a standard Bendix R-12 relay valve (with 4 port) and a pressure regulator (it doesn't permit air to pass through until a preset pressure is reached, usually 65 or 95 pounds) dangling by nylon tubing. I'm sure the howling you heard was your rear brakes engaging as the parking brakes began to set up. No low air buzzer? Just lights and a gauge? Why wouldn't the manufacturer just tee off your existing relay emergency valve? Was that R-12 added by your toad brake supplier? I carry an assortment of tubing fittings in various sizes so I can cap a line if necesary so I can get off the highway and to a service provider.

[Joe Cannarozzi]

Can you say M&G

[Denny]

Bruce,

Don't hesitate to call Peter at Air Force One. About six weeks ago he called me and said he was sending me a new, updated tank assembly because of some problems that became apparent after all the units he sold and installed at Sevierville. I did receive the replacement and went to his recommended dealer about an hour from me and had it installed.

I did not have any problems with the first tank assembly but he wanted to replace it anyway. He needs to be made aware of your problem since this was the second time (I think) for you.

[Jon Wehrenberg]

I'm with Orren on this one. Upon seeing the picture my first question is why is the relay valve hanging down? Something is wrong if such an important component is hanging by its hoses and worse, if that gets ripped out of there by that spinning driveshaft your bus will puke air at a significant rate and your tag and drive axles are locking up.

Is that relay valve a part of the toad braking system? If so why wasn't it bolted in place?

I also carry a mixture of caps and plugs so if I have an air system leak I can stop the loss of air. I may lose a part of my braking system such as the service brake to a wheel or an emergency brake on a wheel, but at least the air is not leaking and I can drive to a repair facility. With an auxiliary braking system I would insist on having shut off valves where the installer taps into the bus. And if the installer held that relay valve in place with nylon wire ties I would seriously question the integrity of their entire product line.

Anybody that has that braking system needs to do an inspection of the system installation and add those shut off valves. Another reason why owners need to monitor the work done on the coach.

[0533]

Your picture shows a standard Bendix R-12 relay valve (with 4 port) and a pressure regulator (it doesn't permit air to pass through until a preset pressure is reached, usually 65 or 95 pounds) dangling by nylon tubing. I'm sure the howling you heard was your rear brakes engaging as the parking brakes began to set up. No low air buzzer? Just lights and a gauge? Why wouldn't the manufacturer just tee off your existing relay emergency valve? Was that R-12 added by your toad brake supplier? I carry an assortment of tubing fittings in various sizes so I can cap a line if necesary so I can get off the highway and to a service provider.
Hello Orren,

I am not nearly a well versed about this as I should be, but could I ask a few questions.

1. The Howling sound while driving off the ramp seemed to be escaping air from under the drive axle. The pressure on both dash gauges were reading 120 lbs, and no low air pressure lights or alarms were on.

When I arrived at the RV park where I leave the bus and was setting still the howling sound continued, but the air pressure began to drop until it reached 80lbs, then the howling noise stopped.

I inspected the bus carefully and did not notice any damage or heating around the brakes of the bus or the toad. I am very concerned by your and Jon's comments about the drive and tag service brakes being on while driving along at highway speeds. When my brakes are applied I see a light on the dash that shows that the brakes are on, is this light attached to the pedal and not the actual brake, and if so then why did I not see red hot brakes or even some smoke or something. I am getting increasingly more upset about this whole dam experience.

I do know that the Air Force One install taps air from the main or secondary tank, but know that it runs to the R-12 Relay you mentioned, then to a small air tank installed by AFO) then to the toad.

I think that somehow the drive train catches the line or hits the R-12 relay and severs the fitting from the R-12 to the AFO tank and the end result is that it falls onto the spinning drive shaft (PS> scrapping up against it leaving lines scraping around it, hope this does not damage this shaft).

I was under the impression from AFO that in this event there would no effect on the main braking system, but it does not appear to be so as it must be placing a stress on the entire system trying to keep the air pressure up for braking. I also wonder how effective the brakes would be in an emergency braking situation??

Finally I am not a big fan of going under the bus to fix for the second time an install that should not require any service and repair.

My plan is to raise the bus on one side, place the Prevost hydraulic jack under the jack point on the high side, go under and cut the line from the R-12 to the Prevost air tank, crimp and secure the cut line, seal it somehow and then have the entire thing removed and start over, including careful inspection of the drive shaft.

When this happened before I had Prevost Jacksonville reinstall the unit make a new fitting for the R-12 unit and place the whole thing out of the way of the drive shaft so this would not happen again. I do not feel that AFO has completely engineered this install for our buses to insure against this happening?

[Jon Wehrenberg]

The system check valves are doing their job, and the broken fitting was located so the valves could work.

However, the lines to the relay valve appear intact, but one of them had been laying against the driveshaft and it was a question of time before it would have failed. When that line let go it became another air escape point. If the remaining line was then severed you have a third air escape point.

I am surmising the relay valve is not one originally installed on your coach, but is dedicated to the aux braking system. Even at that it should have been secured to the coach in the same manner as the original equipment valves are and the fact that it is hanging and is a few driveshaft rotations away from being ripped off tells me its mounting was inadequate.

Should you have an air loss that is in a location where the safety valves will not stop the leak your braking system air pressure will drop and once it falls to around 40 or 50 PSI your emergency brakes are going to automatically apply. It can be said the installation was a good one because you were protected from a catastophic air loss, but if my interpretation of the picture is correct and your relay valve was hanging as shown and the air lines were rubbing against a spinning driveshaft as it appears you could very well have experienced brake lockup.

[0533]

The system check valves are doing their job, and the broken fitting was located so the valves could work.

However, the lines to the relay valve appear intact, but one of them had been laying against the driveshaft and it was a question of time before it would have failed. When that line let go it became another air escape point. If the remaining line was then severed you have a third air escape point.

I am surmising the relay valve is not one originally installed on your coach, but is dedicated to the aux braking system. Even at that it should have been secured to the coach in the same manner as the original equipment valves are and the fact that it is hanging and is a few driveshaft rotations away from being ripped off tells me its mounting was inadequate.

Should you have an air loss that is in a location where the safety valves will not stop the leak your braking system air pressure will drop and once it falls to around 40 or 50 PSI your emergency brakes are going to automatically apply. It can be said the installation was a good one because you were protected from a catastophic air loss, but if my interpretation of the picture is correct and your relay valve was hanging as shown and the air lines were rubbing against a spinning driveshaft as it appears you could very well have experienced brake lockup.
I never experienced a loss of pressure while at highway speeds or even while at my first stopping location (red light). Not until I got to a the rv park and applied the parking brake did the pressure start to drop below 100lbs or so. It dropped to about 80lbs then the noise stopped. I then checked the bus for damage and found the hanging valve. I then released the parking brake and backed up the bus into its slip. The air pressure never rose above 80-lbs and the noise never returned. I assumed the tank suppling air to the valve had lost all of its air and now was locked out, but now I'm guessing if I were to have gotten back up to highway speeds the pressure would increase beyond 80lbs and the noise of escaping air would have started again.

My job now is to safely remove this line and seal off the fitting or the line itself to allow me to head back to Prevost for repair.

I must say it is very unsettling to rely on after market installs on these big buses and have such a poor result.

As a pilot, I should have been more involved in this install in the first place considering what was involved (air System), I was distracted by the POG events and was not there during the actual install process.

The funny thing here is that I got rid of my ridiculous Blue OX brake at the rally for this one and now am back to square one, plus now I am chasing my tail to figure out a way to get my Bus braking back to some degree of normalcy.

[garyde]

I have only read a little regarding this thread from the beginning when some people had this system installed in Sevierville. My question , is it legal for a after market company to cut into the air braking system on these coaches? I believe Prevost has to certify their coachs for the US and Canada with their braking system as it was originally designed. Does this not create a Certification issue. Maybe this Company, Air Force One, is allowed to modify Prevosts air system and re certify but it appears they don't have a fail safe design.

[Jon Wehrenberg]

Their system duplicates and runs in parallel with the bus braking system. Other braking systems just tap into the relay valve. The fact that Bruce was able to maintain sufficient air pressure shows they are maintaining the integrity of the original braking system.

Don't overlook the fact that Prevost JAX had its hands in this also. To have a relay valve hanging by its air lines suggests to me that both parties have an equal share in failing to create a more substantial installation. I think it could be argued that it was the falling relay valve and its likely contact with a driveshaft that caused the broken fitting this time. I see the failure to adequately secure the valve as the source of this round of problems.

Based on that opinion which can be completely wrong, I suggest everybody with the braking system get it inspected to insure the valves are properly secured and if it were my coach I would add shutoff valves where the Air Force One system attaches to the coach should there still be problems with that system.

[Jim Skiff]

I spoke with Peter in Minnesota and he has re-engineered the product. He also appears to be very responsive to POG issues related to Air Force One.

I'll see if he can respond here.

[0533]

Their system duplicates and runs in parallel with the bus braking system. Other braking systems just tap into the relay valve. The fact that Bruce was able to maintain sufficient air pressure shows they are maintaining the integrity of the original braking system.

Don't overlook the fact that Prevost JAX had its hands in this also. To have a relay valve hanging by its air lines suggests to me that both parties have an equal share in failing to create a more substantial installation. I think it could be argued that it was the falling relay valve and its likely contact with a driveshaft that caused the broken fitting this time. I see the failure to adequately secure the valve as the source of this round of problems.

Based on that opinion which can be completely wrong, I suggest everybody with the braking system get it inspected to insure the valves are properly secured and if it were my coach I would add shutoff valves where the Air Force One system attaches to the coach should there still be problems with that system.
Good morning Jon,

It is a bit ironic that when I first had this problem back in April just after it was installed Prevost Jacksonville sort of scratched their heads when they saw the valve dangling down. They were not impressed by the device or the install, but more as a favor to me than anything else they repaired the broken fitting and placed the valve further away from the top of the drive shaft.

Prevost Jacksonville did not re-engineer the install or even give it much time or thought as it was not part of their planned service program.

I should have demanded that Air Force One have the entire install redone and certified that it would not or could not happen again. Frankly AFO should have done this on their own.

My bus is not designed differently than others, but for some reason has been having this problem.

The only possible difference ( I would love to hear from others who have the install) is that I have been out on the road non stop since the install traveling running up miles and ending up in all sorts of places. This is no excuse but might help better understand why the install is not robust enough to standup to the rest of the Prevost systems.

Its also possible that this one install was done differently, and the tank and valve were placed in the wrong place, too close to the drive shaft and the drive shaft well.

Today I plan on making a close examination of the failure and decide on a fix before heading back up to Prevost for repairs. I will report on my findings.

[phorner]

Bruce,

Mine failed exactly like yours: the small nipple shearing between the tank and regulator.

This has been re-engineered to eliminate the small nipple. Apparently, this has been the trouble spot. Even nipples that have been replaced have failed, which leads me to believe that it wasn't simply a batch of defective nipples in the original setup.

Good luck in your repairs. I know what a PIA it can be. The good news is that Peter will see to it that you get a replacement unit installed.

[0533]

Bruce,

Mine failed exactly like yours: the small nipple shearing between the tank and regulator.

This has been re-engineered to eliminate the small nipple. Apparently, this has been the trouble spot. Even nipples that have been replaced have failed, which leads me to believe that it wasn't simply a batch of defective nipples in the original setup.

Good luck in your repairs. I know what a PIA it can be. The good news is that Peter will see to it that you get a replacement unit installed.
Thanks for the heads up on this Paul. It is a shame that AFO did not contact each of us to offer the fix, even if it was not the right one.

No one has mentioned the possibility that when this failure occurs while driving over the road, toad attached, maybe even heading down a steep grade finding ones self needing to apply full braking to both the bus and the toad, what then???

I am feeling a bit stupid, and somewhat skeptical now about Rally deals, doubt if I will ever fall prey to these types of carefully crafted products at rallies.

The fact is that even the so called mainstay products can fail, as my Blue OX did which led me down the AFO path in the first place.

I will report back when AFO has weighed in on how to handle the problem.

[Jon Wehrenberg]

I'm no engineer, but I know first hand how vibrations can destroy or disassemble almost anything, and if I were to guess a hard connection between the relay valve and the tank is likely subject to damaging vibrations.

I see no reason why both cannot be mounted to the coach frame up in the area near the tag axle three port Norgren and joined by means of a short length of flexible tubing.

That location may involve drilling some holes and either tapping them or inserting a riv-nut but then both components would be secure. There is also ample room on the bulkhead forward of the drive axle to install these components if drilling the drive/tag axle subframe is not permitted by Prevost. The point being that the quality and strength of the installation should be no less secure than the installation of our relay valves and air tanks.

[phorner]

Jon,

You are exactly right. The replacement components (tank and regulator) are joined by a short length of flexible tubing instead of the short nipple. This eliminates the problem of nipple failure, which was probably caused by some vibration or other harmonic occurence.

[0533]

Jon,

You are exactly right. The replacement components (tank and regulator) are joined by a short length of flexible tubing instead of the short nipple. This eliminates the problem of nipple failure, which was probably caused by some vibration or other harmonic occurence.
Kind wish that the good old boys at AFO had offered this repair to all of us lesser beings.

I am not too keen on crawling under my bus to make temporary repairs to be able to run down the road safely to have this dealt with by Prevost..

As a courtesy and as a good business practice we all should have been contacted and upgraded, and we simply were not.

[phorner]

In all fairness to SMI, they did, in fact, call me before I had a failure. They wanted to make arrangements to replace mine as they were seeing a pattern of failures on units installed at the POG rally. I informed them that at that point, and after several thousand miles, that everything seemed fine, yet they still wanted to swap mine out for the re-designed model.

Unfortunately, mine did fail, exactly as they described that it might, before they had a chance to change mine out. We were on our way to the FMCA Rally in St. Paul when it happened and Peter arranged to meet us on his way there to make the fix. The campground where this work took place is another story for another time :eek:

Peter did mention that he was trying to contact everyone that had had an installation performed in Tennessee so that he could make arrangements for the change.

[Will Garner]

Bruce,

First, let me say that I regret you seem to be having repetitive problems with your AFO Supplemental Braking system.

Second, I must also say that I have had excellent response to my communications with Peter Schenk, owner of SMI. In fact, we had told him of a possibility of being through Evansville in late June or early July. Our travel plans changed to where we would not have been going through Evansville. On the morning we were eastbound leaving Kansas City Peter called me to find out when he could expect me to be in Evansville for him to check my AFO installation and if necessary, install a new unit. We revised our travel plans to go to Evansville and have Peter check our unit. Turned out the unit was fine and I did not need a replacement. I did however inquire as to why I was killing batteries in my towed vehicle. Well when the towed brake pedal is pulled down by the AFO unit to apply towed vehicle brakes, my towed's factory brake lights come on also. Peter devised a cutout relay that takes the factory brake lights out of the equation when the AFO is active. No further problem with the battery. This modification was performed at no cost.

So finally let me say that communication is a two way street. It might be more beneficial to you and other POG members, to simply pick up your phone and give Peter a call. Here is their 800 number from their website which has a link directly from the POG opening page.

1-800-893-3763

Now for a little background information. Prior to purchasing a towed braking system I posted a question on the POG forum about towed braking systems. I did not care to have another device to install and remove from the towed vehicle. Yes, I researched M&G but they do/did not make a unit for my towed vehicle. They say there is no room under my towed's hood for their unit. I got feedback from Lew and he had an AFO in a Saturn towed with which he was satisfied. Now Lew just does not go spreading Lewbucks everywhere so I thought maybe there is something I can get done with an AFO unit. I got in touch with Peter before the Sevierville Rally and he was willing to come to the rally to do my installation and use my installation as a seminar for the rally. It was not his intention to sell everyone a system since he only brought two with him. He had to get other units shipped in to meet the numerous POG member requests for installations on their towed vehicles.

I think you said earlier that a Prevost shop did the upgrade following the first failure. If the location of the installation was a problem it seems to me as if they could have moved the unit with little effort and there would be no need for this discussion.

Again, I regret you are having this problem, I am joyous that there was not a safety consequence, and I am certain that Peter Schenk will stand behind his product.

I do hope you get a permanent fix for your problem this time around.

[0533]

In all fairness to SMI, they did, in fact, call me before I had a failure. They wanted to make arrangements to replace mine as they were seeing a pattern of failures on units installed at the POG rally. I informed them that at that point, and after several thousand miles, that everything seemed fine, yet they still wanted to swap mine out for the re-designed model.

Unfortunately, mine did fail, exactly as they described that it might, before they had a chance to change mine out. We were on our way to the FMCA Rally in St. Paul when it happened and Peter arranged to meet us on his way there to make the fix. The campground where this work took place is another story for another time :eek:

Peter did mention that he was trying to contact everyone that had had an installation performed in Tennessee so that he could make arrangements for the change.
I guess he did not have my phone number. I plan on calling him today to make arrangements for the fix.

Thanks again Paul, will let you know the outcome.

PS> Do you have a good number and Email for Peter??

Thanks

[phorner]

Bruce,

Try 812-483-3507. Their main number is 800-893-3763.

I know first hand just how frustrating this can be. I am confident that Peter will do everything he can to make things right for you.

Be safe....

[Denny]

Ditto on what Paul said; I posted the same on #51 of this thread. With all of the legal ramifications involved, I think Peter is protecting himself and also trying to keep the customers, that's us, happy. He has gone out of his way to contact us when the first problems arose and to resolve the problems. He posted on POG letting everyone know there that there was a problem. Monday morning quarterbacking, I would purchase the system again.

Peter is a fine Christian man and runs his business with good Christian ethics and will see that this problem is corrected to Bruce's satisfaction.

[0533]

Ditto on what Paul said; I posted the same on #51 of this thread. With all of the legal ramifications involved, I think Peter is protecting himself and also trying to keep the customers, that's us, happy. He has gone out of his way to contact us when the first problems arose and to resolve the problems. He posted on POG letting everyone know there that there was a problem. Monday morning quarterbacking, I would purchase the system again.

Peter is a fine Christian man and runs his business with good Christian ethics and will see that this problem is corrected to Bruce's satisfaction.
I do not question Peters integrity. I feel it is my duty to inform all POG members (As I did the first time) to allow each of you to both examine your own install and weigh in on what we should be inspecting and "WHY" and "HOW" to ensure a proper repair and provide for a long term and safe operation.

I really belief that Peter has actually benefited from the responses from people like Jon and Orren and others who have years of experience with Prevost Buses and can offer first hand input and useful ideas to overcome this very real problem that can compromise safety.

This forum has many self employed entrepreneurial men and women participating, and each including myself who wants this system to work out for its inventor (Peter) we, I just want the bugs worked out and the system to have the same robust install and life expectancy as the rest of the Bus.

I like the idea when I first saw it, I did not try and haggle over the price, I assumed that Peter new and understood the Prevost bus and the necessary install that was needed to create a satisfactory and safe installation in this critical aspect of the operation of the bus.

I am sure like you that Peter will offer his response and will do what is necessary to make this right for me and all others who have the system in their buses.

I also know that Peter needs to create a better mousetrap for Prevost Buses than he has currently out in the field and my two failures are a good example of what can and has happened.

When Peter responds to my email to him, pics etc. I am sure he will offer his planned solution for retrofitting our buses.

[0533]

Bruce,

First, let me say that I regret you seem to be having repetitive problems with your AFO Supplemental Braking system.

Second, I must also say that I have had excellent response to my communications with Peter Schenk, owner of SMI. In fact, we had told him of a possibility of being through Evansville in late June or early July. Our travel plans changed to where we would not have been going through Evansville. On the morning we were eastbound leaving Kansas City Peter called me to find out when he could expect me to be in Evansville for him to check my AFO installation and if necessary, install a new unit. We revised our travel plans to go to Evansville and have Peter check our unit. Turned out the unit was fine and I did not need a replacement. I did however inquire as to why I was killing batteries in my towed vehicle. Well when the towed brake pedal is pulled down by the AFO unit to apply towed vehicle brakes, my towed's factory brake lights come on also. Peter devised a cutout relay that takes the factory brake lights out of the equation when the AFO is active. No further problem with the battery. This modification was performed at no cost.

So finally let me say that communication is a two way street. It might be more beneficial to you and other POG members, to simply pick up your phone and give Peter a call. Here is their 800 number from their website which has a link directly from the POG opening page.

1-800-893-3763

Now for a little background information. Prior to purchasing a towed braking system I posted a question on the POG forum about towed braking systems. I did not care to have another device to install and remove from the towed vehicle. Yes, I researched M&G but they do/did not make a unit for my towed vehicle. They say there is no room under my towed's hood for their unit. I got feedback from Lew and he had an AFO in a Saturn towed with which he was satisfied. Now Lew just does not go spreading Lewbucks everywhere so I thought maybe there is something I can get done with an AFO unit. I got in touch with Peter before the Sevierville Rally and he was willing to come to the rally to do my installation and use my installation as a seminar for the rally. It was not his intention to sell everyone a system since he only brought two with him. He had to get other units shipped in to meet the numerous POG member requests for installations on their towed vehicles.

I think you said earlier that a Prevost shop did the upgrade following the first failure. If the location of the installation was a problem it seems to me as if they could have moved the unit with little effort and there would be no need for this discussion.

Again, I regret you are having this problem, I am joyous that there was not a safety consequence, and I am certain that Peter Schenk will stand behind his product.

I do hope you get a permanent fix for your problem this time around.
I like you am sure that Peter will stand behind his system, and in no way feel that he will not.

I have emailed Peter all the necessary info to start his investigation and hope that he has a plan for a better install.

As for Prevost Jacksonville, they simply reinstalled the old part back onto the tank etc. They did move the valve and lines away from the driveshaft well so it would not come in contact with the shaft, but in no way did they re-engineer the install or get any direction from Peter (to the best of my knowledge) on what was needed to make the repair. It was done as a courtesy to me and to help get me back on the road.

I think it is great to have a strong working relationship with Peter, and am still pleased that we were introduced to Peter and his product, but all of this does change the fact that the system needs major improvements to be worthy of an install on our buses.

I plan on sticking it out with Peter in hopes that we can all have the kind of result we had expected in the first place.

I am sure that Peter will keep all of us informed on his plans.

As I have stated in our responses, my bus is like yours, but possibly I have been out there using it more than some, not sure, just feel that if each of you are not fully aware than the end result might not be the correct one.

[lewpopp]

I am embarrassed to say that the AFO I presently have is not the original set-up that was installed by one of Peter's "authorized" shops.

It was a Stay-N-Play and wasn't worth a s-it. Peter agreed with me and said it should never have been put on the Prevost.

I went to another "authorized" AFO shop and they changed a lot of things out and Peter supplied the changed equipment.

Needless to say I was out another $550 bucks for the labor of which I was not the slightest bit happy. I presently have over $2100 Lewbucks in this and I'm still not satisfied and now I'm scared about it's performance.

I do not have an airtank in my system (why?) and my airline runs directly from my service line at a brake chamber. The installer said the coach could make up much more than the air lost if it should break loose so that should not be a problem.

Peter, you can expect my call soon.

I had mine installed after the Sevierville rally. I did not have nor did I say I had an AFO and I was misunderstood. I'm sure we could look up what I said in response to the question of the system I had. Perhaps I made the response over the e-mail

[0533]

I am embarrassed to say that the AFO I presently have is not the original set-up that was installed by one of Peter's "authorized" shops.

It was a Stay-N-Play and wasn't worth a s-it. Peter agreed with me and said it should never have been put on the Prevost.

I went to another "authorized" AFO shop and they changed a lot of things out and Peter supplied the changed equipment.

Needless to say I was out another $550 bucks for the labor of which I was not the slightest bit happy. I presently have over $2100 Lewbucks in this and I'm still not satisfied and now I'm scared about it's performance.

I do not have an airtank in my system (why?) and my airline runs directly from my service line at a brake chamber. The installer said the coach could make up much more than the air lost if it should break loose so that should not be a problem.

Peter, you can expect my call soon.

I had mine installed after the Sevierville rally. I did not have nor did I say I had an AFO and I was misunderstood. I'm sure we could look up what I said in response to the question of the system I had. Perhaps I made the response over the e-mail
I have had a good conversation with Brent from AFO. Brent has explained to me what has been going on with the AFO systems installed on our buses.

First Brent explained that they have discovered that the vibration (harmonic) that somehow gets setup under the bus while driving down the road has been the source of the problem.

There was a connection between the tank and the valve (nipple). This nipple was in fact the point of connection and was the point at which all forces were applied.

I think that Brent and Peter have taken a long look at their Prevost installs and now realize that thy were not engineered well for our buses.

In my case Brent has or is about to send along the new improved version of the product to his trusted Orlando Dealer for install in my bus.

It is an interesting process following the progression of this product and its evolution.

In my case when the parts vibrated the nipple off it actually caused the entire install to come apart including having the tank break away from its bracket/secured location and fall back behind the bus striking the toad.

I have stated this before in this thread, but feel it is worth mentioning it again and even expanding this discussion to recap what has been accomplished as a result of threads like this one.

By bringing these problems to light and sharing them with experienced Prevost owners in this thread, we have been able to troubleshoot Peters problem, possibly saving Peter time and even reducing future liability that could have been the consequence of future failures.

I think that Jon nailed the problem when he stated that the install needs to be made hard to the Prevost frame, and that this must be part of the overall product installation program. I also believe that as Jon said there needs to be an inline shout off in the event of a failure.

I know how important it is to create a product that is price competitive and good and realize that adding these additional steps will increase the overall cost, but am certain that the extra hour of install time and the inline shut off will be well worth the expense.

In my case I plan on making sure that not only are the new and improved parts installed but (based on the fact that all of my components vibrated off the bus) that I get the 1. the location carefully inspected for best result 2. That the parts are carefully secured to the bus frame 3. That a shutoff is placed inline.

I have owned like you guys lots of stuff, and have been the guinea pig in more than one time including aircraft and boats, from crappers to fuel injection and feel that in this case we can actually work with Peter and his team to help him (and ourselves) improve and make his good idea a truly better mousetrap.

[Jon Wehrenberg]

The locations have the potential to vary because the buses vary. Prevost has evolved the buses to the point at which later models have accumulator tanks plumbed directly to the air bags. Those tanks occupy space that would be great for the braking system. So earlier models (early "T" and prior) would have plenty of room, but on later models it may be a challenge.

What Peter needs as a manufacturer is to see a variety of coaches and find the spot that is universal to all of them so he has a standard "Prevost" product. Once he has that place selected then the devlopment of attachments and connections and subsequent testing can take place. I strongly suspect that if the relay valve and tank are secured properly, and all connections to those devices have at least a short flexible section these problems now being encountered go away forever.

He cannot count on spaces in the engine compartment because converters use that space differently and the only area I have ever seen that converters typically do not do anything with is on the frame and across the top between the drive and tag axles.

[Joe Cannarozzi]

What would be the down side of extending the connecting air line to the bus so the device could be mounted in a more assessable location, like the engine compartment?

[Jon Wehrenberg]

Converters all use the engine area differently. Virtually all the space accessible through the rear doors is occupied or required to access something, like the electrical box.

That leaves the RH side door above the batteries. Unfortunately that space is occupied in various ways also. Some coaches have house batteries above the chassis batteries and some have boxes designed to hold sewer hoses or other stuff like emergency reflectors.

I don't think AFO can approach every Prevost as a custom installation. They would go nuts trying to fabricate brackets and supports and other mounting devices depending on the type shell, the age of the shell or the converter.

So if the engine area is out, the next logical place is on the forward bulkhead in front of the drive axle. Unfortunately Prevost has used that space to mount the system for the hydraulic stabilizators on some coaches, and some converters like CC have used that open space to hold a condensing coil for their AC system making access to the bulkhead out of the question.

Behind the front bumper? Nope, some fill it with Cruise Airs, others have a drawer there, and some use it for things like the aux air compressor.

Steer compartment? Nope, some owner have hose reels or aux air compressors there.

In a bay? Nope, no two converters use bay space the same so there wouldn't be anything standard there.

That leaves between the tag and drive axles, and even that is going to be tough standardizing because of the accumulator tanks.

[0533]

The locations have the potential to vary because the buses vary. Prevost has evolved the buses to the point at which later models have accumulator tanks plumbed directly to the air bags. Those tanks occupy space that would be great for the braking system. So earlier models (early "T" and prior) would have plenty of room, but on later models it may be a challenge.

What Peter needs as a manufacturer is to see a variety of coaches and find the spot that is universal to all of them so he has a standard "Prevost" product. Once he has that place selected then the devlopment of attachments and connections and subsequent testing can take place. I strongly suspect that if the relay valve and tank are secured properly, and all connections to those devices have at least a short flexible section these problems now being encountered go away forever.

He cannot count on spaces in the engine compartment because converters use that space differently and the only area I have ever seen that converters typically do not do anything with is on the frame and across the top between the drive and tag axles.
Hello Jon,

I am about to repair the 3 lines that need to be addressed today. There are 3 lines to deal with, one that is almost cut off anyway that goes to the Toad from the front of the R-12 valve. On the backside of the valve is the supply line from the main bus air, then there is a line attached to a female connector that went to the AFO air tank which is now somewhere on 95.

You mentioned that "buses to the point at which later models have accumulator tanks plumbed directly to the air bags".

My question to you is: As part of my plan today is to raise the bus up on one side, place the Prevost jack under the raised side jack point and then crawl under and cut all 3 lines away from the R12 valve and the other small valve, seal them off so that I can travel.

Question: Is there any chance that by having raised the bus up on one side, and making these cuts that I might be affecting the air supply to the airbags???

I do not mind being stupid in these circumstances and would rather have a better understanding of what I am about to undertake.

Only 1 of the 3 lines seems to be live, the one that is coming into the backside of the R-12 valve which is not doing anything now as the air pressure is now at or below 80lbs as the bus compressor is no longer trying to supply air.

I am probably being overly cautious, but better safe than sorry. My wife is giving me a hard time about going under the bus.

[Jon Wehrenberg]

I think I understand the AFO system (I actually think it is a great system) and if my interpretation is correct there should be only one line under pressure. That line should be coming from the bus brake system pressure tank to the relay valve for the AFO system.

Unless and until you step on the brake pedal there should be no other lines pressurized. What is important for you to understand is that one line is likely a signal circuit coming from the brake treadle. That line must be securely capped or its origin plugged. The line from the bus brake system tank to the relay valve must also be capped or its origin plugged. Doing that will restore your bus to the way it was prior to the installation of the AFO device.

As to getting under your coach. If I were you I would raise the entire rear of the coach to its maximum. I would then put an unextended hydraulic jack under the rear support points behind the tag axle on both sides. For $60 you can go to a Northern, or Harbor Freight or any store that sells jacks and get a pair that are rated around 20 ton, and which have a center threaded adjustment. With the adjustment all the way out and the jack fully collapsed the weight of your bus will be fully and safely supported. To make sure the jack is adequately supported on the ground I would go to my local Lowe's and buy a 2 X 10, 8 feet long and get the guy there to cut it into 16" lengths (you end up with 6 pieces) and put them under the jacks to distribute the weight. That way even if the concrete is thin, or the ground is soft the weight is distributed and at an 1 1/2 thickness each you can adjust the jack threaded center to touch the body support point. Make certain the jack is under the correct body support point which is a 2 X 6 (guessing at the size) vertical tube member behind the tag axle and which likely has a heavy square tube running from the bottom of the one on the LH side to the RH side. If you have any doubts I will take pictures, but I think you will see the correct points

Your bus will be very safe to get under because once you raise it fully, and turn off the key the Norgrens will lock the air into the tag and drive axle air bags, and isolate them from the rest of the bus air system. Even if you purge all air from both brake systems and the aux system your air bags will remain inflated (unless you are experiencing the leans).

You can safely get under the coach because your air bags and tires are the primary support, and if you should somehow cut or break a line to the air bags the jacks will still support the coach.

The good news is that once you slide under the coach you can sit up and actually move quite freely in the area between the wheels.

Tell Pam you will be very safe if you do this, or let her read this post.

[Jon Wehrenberg]

Bruce,

I found this picture. This is the rear support point I am talking about.

I used two jacks in this picture because I did not have stands when it was taken.

[JIM KELLER]

Jon, Is this the same point we should use to support the Bus with the stands several of us purchased from you ? If so the small square tube would rest on the top of the stand. Correct ?

[0533]

Thanks Jon,

I will find the necessary jacks and lumber and go to work.

Brent at AFO wanted me to go to NAPA and get a couple of qtr. inch nylon female air fittings to make a temporary seal on the offending airlines.

I went to NAPA and they did not have anything that would work on the black air lines.

I am going to crimp and secure the lines with 3 wire ties on each crimped line, super gluing the open ends and wrap all in tape. I think this will provide a temporary fix that will allow me to drive the 160 miles or so to get a real repair.

[0533]

Great shot, this helps me better understand what is needed.

[Orren Zook]

Bruce,

while you're under the coach could you take a couple photos of how this device is plumbed up - I'm having a little trouble picturing it. Thanks in advance.

[phorner]

Good luck, Bruce.

If you happen to have any "Rescue Tape", it will hold against considerably high pressure and can be used after you crimp the offending air line(s) in addition to, or instead of, the wire ties.

Take plenty of time to secure the jacks and assure yourself that the bus is supported. We took the better part of an hour to study/jack/support the bus before anyone crawled underneath.... to make a fix that only took a couple of minutes.

Be safe and we're all hoping for a good, and final, solution :)

[0533]

Bruce,

while you're under the coach could you take a couple photos of how this device is plumbed up - I'm having a little trouble picturing it. Thanks in advance.
I will be happy to take some pics, but unfortunately much of the install is either dangling from its air lines or has completely left the bus for a better place somewhere along I-95, but I plan on taking some and will share them with everyone.

[Jon Wehrenberg]

Bruce, It would be easier to follow the AFO installed lines to their origin, remove them and just use a 3/8" or 1/2" plug.

Orren, If I am wrong I assume Peter from AFO will jump in and slap me, but the relay valve is getting a signal from the brake treadle, and the relay valve is taking air from the brake system air tank and is passing it through the relay valve (modulated by brake treadle signal pressure) to the toad braking device under the hood of the toad.

I don't know if the tank is the supply to the relay valve or is downstream from it (I suspect it is the toad relay valve supply).

That air pressure to the toad, modulated by the relay valve is used to maintain vaccum on the toad brake vacuum booster via pressure venturi installed on the toad, and to actuate a pneumatic cylinder to actuate the brake pedal.

I'm pretty sure, but if wrong this needs to be corrected.

[Orren Zook]

My problem visualizing this is - how does the second relay valve, I'm assuming installed by AFO, get it's signal to operate. Is another service line installed from the foot valve to this relay valve? Does the R12 receive it's air supply from one of the main system tanks? If not, where does the air supply come from? And what is the purpose of the small air tank shown in the earlier picture? Does it supply the cylinder in the toad that operates the brake? I took a brief look at their web page but didn't see any schematics.

[Jon Wehrenberg]

Hopefully Peter will chime in and post the correct answer. I suspect the signal from the foot treadle is picked up somewhere, perhaps a "T" off the line at the Prevost relay valve.

I suspect the tank is installed to serve the toad, and it picks up a protected line from the Prevost installed braking system tank. I am sure that line protection is what kept Bruce from dumping all his air. I suspect that might also tee off a line perhaps at or going to the Prevost relay valve.

At least that is what appears to be a logical approach. I seriously doubt if they would run a parallel line from the treadle, so they created a miniature version of the bus braking system picking up the air signal and tank pressure (to their relay valve) at convenient spots in the rear.

[0533]

Good luck, Bruce.

If you happen to have any "Rescue Tape", it will hold against considerably high pressure and can be used after you crimp the offending air line(s) in addition to, or instead of, the wire ties.

Take plenty of time to secure the jacks and assure yourself that the bus is supported. We took the better part of an hour to study/jack/support the bus before anyone crawled underneath.... to make a fix that only took a couple of minutes.

Be safe and we're all hoping for a good, and final, solution :)
Hello Paul,

I have never heard of "Rescue Tape", what is it and where can I find it??

I plan on taking my time with the jacks and will be sending my wife's mother under the bus to take pictures before I start my project.

[phorner]

Bruce, I have posted a link to Rescue Tape. It can be found at most truck stops and hardware stores.

Really good stuff!

http://www.rescuetape.com/


However, Jon's recommendation to follow the lines to their origin and use a plug is the best solution. You just need to have the correct plugs/caps when you start. I wouldn't make a second trip under the bus if I didn't have to, so if you don't have the parts, I wouldn't make a trip under just to take notes and measurements and then search for the correct fittings.

[0533]

Converters all use the engine area differently. Virtually all the space accessible through the rear doors is occupied or required to access something, like the electrical box.

That leaves the RH side door above the batteries. Unfortunately that space is occupied in various ways also. Some coaches have house batteries above the chassis batteries and some have boxes designed to hold sewer hoses or other stuff like emergency reflectors.

I don't think AFO can approach every Prevost as a custom installation. They would go nuts trying to fabricate brackets and supports and other mounting devices depending on the type shell, the age of the shell or the converter.

So if the engine area is out, the next logical place is on the forward bulkhead in front of the drive axle. Unfortunately Prevost has used that space to mount the system for the hydraulic stabilizators on some coaches, and some converters like CC have used that open space to hold a condensing coil for their AC system making access to the bulkhead out of the question.

Behind the front bumper? Nope, some fill it with Cruise Airs, others have a drawer there, and some use it for things like the aux air compressor.

Steer compartment? Nope, some owner have hose reels or aux air compressors there.

In a bay? Nope, no two converters use bay space the same so there wouldn't be anything standard there.

That leaves between the tag and drive axles, and even that is going to be tough standardizing because of the accumulator tanks.
I have sealed off the brake air leak, removed all valves, cut, crimped, sealed, taped, wire tied, glued and wire crimped all lines, tested the bus brake air, 130lbs blew off nicely and seems to be holding well.

I placed 2X12's boards under the Tag axle jack points, placed 2 20 ton jacks at each point plus 2 12 ton can't have too many and went to town.

I must say that even with the bus aired up higher in the back and the jacks underneath with some extra jacking it is still somewhat of a tight space to crawl into, but once there and sitting on your butt looking up there is enough room.

I am still not overly exited about being in and getting to and from this space.

I did not take any pictures because there was not much to offer, as all major parts are either dangling on the ground or simply gone, sorry.

I simply cut away both valves and all three lines, capped them off carefully especially the main line from the Bus air brake. I crimped each line about 8"s, used a mental locking ring, 3 on each line, tape, a new type of super glue in the open end, then heavy duty tape along the entire crimped section, I think it is very tight now. I finally wire tied the finished product up to and along the run of hoses that were wire tied above the air lines, I think it is good to go for a long trip if needed, and with IKE heading at us CAT4 I just might close the shutters, grab some steaks and head on down the road.

[Ray Davis]

Wow, what an ordeal. It's good to hear that you are ready to be mobile again! Best of luck on getting that taken care of. I'm glad to hear that the AFO guys will stand behind it and get you replacement gear.

Ray

[0533]

Wow, what an ordeal. It's good to hear that you are ready to be mobile again! Best of luck on getting that taken care of. I'm glad to hear that the AFO guys will stand behind it and get you replacement gear.

Ray
Thanks Ray,

I will let you all know how the reinstall goes next week.

[0533]

While up on the lift at Prevost car checking for air leaks replacing Norgren valves spending money etc I had the mechanic spray his soapy water all over the new one piece SMI Toad Brake system to check for leaks, the system had five leaks in it at every connection.

I had it removed and placed on the work bench, replaced all connections had each carefully installed and torqued down and reinstalled the entire system and really screwed down this time, no leaks now, 2 hours of tech time.

Here is my conclusion about the system. It does work and the idea is good, but the install done under the bus on the ground by folks who in my case may never had any experience under a bus is not the perfect way to install an important item as this is. I would not have it done by anyone who has no Bus experience and not unless it is in the air and easy access.

And finally the actual parts could be better more robust for the application in my opinion, they do not look as strong and sturdy as the rest of the Prevost air system is.

I like the guys at SMI and respect their idea and realize that the added cost and time required to have our buses up on a rack would add real $ to the overall install, but if you add up the expense , in my case to replace the system and, repair it twice now the extra cost for a more robust version installed properly would not have been expensive in the long run.

I do recommend SMI but please make sure it is installed by qualified people with Prevost experience under the right conditions.

[phorner]

Bruce,

I strongly agree. The system is good...... but the install could (and should) have been much better.

Next time I'm under I want to check for leaks.....

[JIM CHALOUPKA]

Thanks Bruce, I've been waiting for your final opinion.

JIM

[Kenneth Brewer]

For a shop installed (most likely Camping World) Brakemaster system, where is the brake (air) line connection made? I gather it is teed off one of the wheel brake cylinder actuator lines with a fitting (tee) that replaces an existing straight fitting? I ask because I need to know beforehand how this should go, typically; we are planning a two month trip this year and I suppose I will tow this time, first time with a towed car rather than a trailer.

Thanks.

[Joe Cannarozzi]

Yes Ken that is where they get it from on the units I have encountered.