A better Understanding of AFO
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
I always wish I had my fishing poles ;-)
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