Front wheel removal of 1998 Prevost XL

[Ben Neumann]

I own my 1998 Country Coach for three years and I decided to change all air bags, they were never changed before. I built myself a pit in order to go safely under the bus. The chassis of the bus is as high as it goes and the front wheel is hanging approx. three inches above the ground. I have trouble getting the front tire out of the wheel well. The tire is about 3/4" larger then the wheel well opening. I have tried to turn the tire in an angle but that did not help. Is it nescessery to remove the fender flare every time you take the tire off? I hope not, that is a lot of extra work. I am hoping that I am doing something wrong and there might be someone out there to straighten me out. Any help will be very much appreciated.
Ben

[Gil_J]

Ben,

Hopefully Joe will chime in given he is a suspension expert.

I've had the front wheels off of my 99 CC and I didn't have any problems. This may be a dumb question, but are you jacking the coach at the jack points in front of or behind the independent front suspension? If you are jacking on the jack point on the lower A arm you probably can't get the wheel off.

[Ben Neumann]

Thank you Gil,
I jacked the chassis in front and behind the wheel to the height that the wheel was three inches above ground. The seller of coach told me, to try to move the bottom of the wheel out of the wheel well first. This finally worked, but still was very tight and I am concerned about putting it back.
At this point, I am trying to remove the old air bag. I loosened all screwes and removed the air fittings. The bag will not come out without removing the upper a-arm. I just looked at the 8 air bags I got from Prevost. All new bags are approx. 9"X 12 1/4". The old bag up front measures 10 1/2" high and 11" wide. I might have to check with Prevost to get an answer. It just does not look wright to me. I will keep you up how the project is progressing. Thank you again Gil
Ben

[Gil_J]

I'm pretty sure the same bags are not used in all positions. There was a change to the recommended front air bag due to the weight on the front axle of most conversions. I would verify with Prevost that you have the right bags.

Yes, the tires generally need to be tilted out from the bottom unless the coach is lifted.

The front bag will come out without removing the A arms. I forget the magic twist that needs to be followed. Keep looking. You can also call any of the Prevost centers or Prevost PASS and a tech will tell you the routing of the bag.

[Joe Camper]

Ben I will see if I can help u. When I first support the chassis I don't jack anything. Go to level low or hwh and go all the way up with all 3 corners, and even if u r not going to do anything with the other 2 corners always up all the way all around. BE PATIENT DO NOT USE HIGH IDLE. If the bus is at 120 psi already, pump the brakes down below 100 to ensure the compressor has started pumping and then continue to remain in the up position on the front at LOW IDLE untill the air dryer pops off. This is the only way to ensure u have the front all the way up with Indipendent front suspension. THE ONLY WAY.

This is quite possibly where u went wrong. U thought u were way up in the front but in reality were not. That's why the tire was not clearing for u.

Once u get to know your bus u will learn if your chassis requires this extreme . Some r heavier than others. Some front ends r so heavy they require this process twice to get fully extended for service or repair . Other chassis preform wonderfully.

At that point go in the pit and support the chassis at the lifting points with jack stands that r within 1 in of tight or tighter. Don't need to go so tight as so when your done u have to jack the chassis to get them out but get them close.

Then dump the air out of the front and let all the air out of the front bags. The closer u set the jack stands the more room will be created between the tire and the fender. So drop it onto the stands, go down. Be patient get all the air out. At that point the tire is den neer off the ground it's just touching.

Just loosten but do not remove lug nuts.

Put a jack on the jack point of the lower a arm and just get the tire barley off the ground barley an inch. Now remove them lug nuts.

Then on the drivers side turn the steering wheel 1 turn towards the pass side and pull out on the bottom of the tire while turning/pulling the front of the tire towards u. Once uve done it a couple times its a sinch. Do not get way off the ground there is no good reason in fact it just makes getting the rim much more difficult to get on and off. When it's barley 1in off the ground it practically tilts right up to the studs.

The air bag if u position the a arm just right u can get it in and out however removing the upper a arm bushing bolts is not too bad a job and allows greater access. The way the geometry is on that mount all 4 bolts need to be all the way out to pull and replace that arm.

Usually there r no alignment shims on the top arms. Usually, but I have seen some up there. Probably because the fit up there is so close even with only 1 shim on 1 bolt and bam, the holes for all 4 bolts barley line up and become a bitch. If a shim is present put bolts first then insert shim and ull have to tap it in, thats way easier .

Incorporate these things and u will be rewarded. May the force be with u.

I think the IFS bags end in 59 but not sure. The bottom bell is steel not plastic. They do look quite a bit different new and old.

The upgrade on the front bags Gill is referring to is for the straight axle front ends. To my knowledge prevo has been using the same front bags for IFS since it's inception.

[billbunch47]

An other trick on the front air bags is to use a vacuum cleaner to suck down or compress the bag to gain clearance, works on the new install also.

[Ben Neumann]

I would like to thank everyone for responding to my thread, esspecially Gil and Joe for taking so much time to explain the procedure to accomplish the task. Yesterday I finished the installation of the new air bags on the front end. I accomplished the removal of the old bag and the installation of the new one in about five hours. On the passenger side I just knew what to do and waisted no time experimenting any more. I found, by removing the upper a-arm the task for removel and installation of the bags was easier then trying to leave the arm in place. I used three slide adjustable c-clamps to squash the new air bag together, taped it with duckt tape to hold it in place before installation. Also the removal and reinstallation of the a-arm was easy. When reinstalling the a-arm, I kept all the bolts loose till the last bolt was inserted. I also kept the center cone (the one who attaches to the C-arm of the wheel assembly) loose. This way it was easy to get the bolts bag through the holes of the mounting brackets. The only difficulty I had was with the weight of the a-arm. When removing and reinstalling this arm you are not in the best position for lifting. A second guy would have been the easy answer.
Today I am going to atack the drive axles bags. I am wundering what I might run into. Thank you again for all the help and I wil keep you up what develops.
Ben

[Gil_J]

The rear are much easier! Did you confirm the bags they sent were the right ones? I noticed my 9u chassis had 3 different bags.

[Joe Camper]

Yes the rears should be a smidge easier.

When u do the rear do as I described up front. All the way up all corners front included. Support the chassis at the lift points with jack stands as tight as u can get them. Dump all rear air both sides. Leave front up. Jack duels just enough to get them off the ground plus just 1 inch. The rims will not be a strain on and off.

U really do not have to take the inner drive tire off unless u want. If u do not just be sure to check the inner nuts for tight even if u have not loosened any often u will found 1 or 2 loose and potentially happening during the outer tire removal but also just plain loose as well. Regardless if u remove the inner drive or not and if u have a valve stem extension the just off the ground suggestion makes putting the outer tire back on and way easier to get the stem extension thru the hole in the outer rim without damage.

When u remove the screws for the rubber flap forward of the drives if u like and if u left the inside duel on u would not remove all the screws. Leave the top inside screw for the rubber flap on and let it lay on the tire it will be out of the way and make going back in easy alignment.

After u have pulled the outer drive tire and before trying to remove and replace the bags drop the jack down at that corner until the inner tire hits the ground this will give u the most clearance.

There is no rhyme or reason to weather the fittings r push in or not. I'd replace any disrupted push in with new old style parker fittings.

Look close at the air tanks attached to each bag for rust at their brackets. Do NOT open or disrupt the drains on those tanks. U will never get any water out of them and ud be potentially creating a suspension leak. I'd plug them get rid of the drains. I'd pull and paint the tanks too if I've got the time.

The top and bottom studs on some bags r the same threads. Some have fine thread on the top and course thread on the bottom. This is so wrong on so many levels but I won't go there!

When installing the new bags paint their mounting plates. Put the bottom in first and compress by pushing down hard and u can push it in, first 1 top stud then the other. U will not damage the threads on the top studs by doing this. Once both studs have cleared the flange position it up. If there is a gap at the top longer than the studs after u have secured the bottom jack that hub back up and the bag will get close enough to get the nuts on the studs. It may be nessessary on the drives to jack the other side up with it . This keeps the suspension carriage square where if u don't u will have to pull and push to get the top studs to line up wit the holes.


If u do replace fittings use Parker only. No home depot no Chinese.

Also if replacing fittings for some reason prevo has half in pipe to 3\4 compression on the front drive bag BUT 1\2 IN pipe to 5\8 compression to the rear drive and tag bags.

That about covers the little things that ud otherwise have to potentially slow u down. If anything else comes to mind I'll add it on the thread.

Gill I'm thinking the drives r 260 the tag is 259 can't recall the steering.

And above all else be careful Ben, do not hurt yourself.

[Ben Neumann]

Yes Gil, I did call Prevost and I have the right bags. They all fit but do look taller and skinnier then the old ones. This is probably because they have never been inflated before. Thank you Joe for your extensive explanation about removal and installation of the rear bags. They are definitly easier to install. When removing the drive axle wheels, I noticed an oil leak on that axle (drivers side) Yesterday I just installed the tag axle bag. Today I need to address the oil leak on the drive axle before I continue with the remaining air bags. I have another issue with my bus. When I purchased the bus about three years ago I noticed there was a problem with the brakes. When stepping on the brake there was always a gap in the brake paddle when stepping on it. In other words, you try to stop in front of a stop light by stepping on the brake and nothing happens. When realizing that the bus would not stop, I would panic and slam on the brake to stop it. When investigating the cause, I found the drivers side tag had frozen brakes and the brake shoes were completely gone to the point there was nothing left and the rotor had 1/4" groves. I repaired this wheel and also checked all the remaining wheels and installed new brake shoes on every wheel. The brakes definitly improved and the gap at the brake pedal disappeared. But still, I feel the brakes are not the way they should be. Last year I changed the master cylinder and it made a slight difference. It is an improved new model whitch looks identical to the old one. Still, I feel these brakes are not save. I need way too much pedal pressure to stop the bus. In an emergency braking I would be in real trouble. I have never driven any other Prevost and therefore have no comparison. I ask my parts supplier for softer brake lining but he tells me it is not available. After I am done with the air bags I am going to attack this problem. At this time I wonder if anyone of you have the same problem. When talking to other bus owners (not nessecerly Prevost owners) I hear comments like "all busses are like that because bus owners do not want to get sued when passanges might get slammed against the front seat if the bus driver hits the brakes to hard. I have heard these comments from several people. I am haveing a hard time believing it and would appreciate your thoughts.
Ben

[Joe Camper]

A semi at 80000 lb on 5axles is averaging 16000lb per axle. A bus that's 54000lb on 3 axle averages 18000lb per axle and that has to be considered.

What r u refering to when u mentioned u replaced the master cylinder??

R your disc brakes Rockwell on the tag and knorr bremse on the steer? Either way those bolts attaching the knorr bremse caliper bracket to the axle housing r for sure some of the most difficult bolts any mechanic will ever encounter. You have to pull it to get the rotor off. They also carry no locking fasteners. They r installed to spec with massive amounts of locktight. That's how they come from the factory. Separating rotors from hubs on Rockwell disc is also very very physically demanding. If u preformed this repair u r stronger than the average guy.

What seal on the drives is leaking? The axle gasket on the outside or the inner hub seal?

Although I would never stab the brakes to test them on a motorhome for all the obvious reasons I'm not entirely confident if I had to that the antilock would actually come to play. Or im not completely confident it is possible on dry road to activate the antilock.

Has anyone out there ever had to panic stop on a dry road and felt the antilock opporating? Ive driven many loaded semi and many different prevo and a loaded semi can stop more comfortably than any prevo motorhome I ever drove but I've thankfully never had to make a real hard panic stop with a bus. My comparison can only be based on normal to slightly harder than normal stops.

[Gil_J]

Ben,

There are 2 different treadle valves and here is what Bendix states:

"The E-10™ dual brake valve (Figure 2) is similar to the E-6™dual brake valve except that a metal coil spring housed inan upper body assembly replaces the rubber spring used inthe E-6™ valve. The use of a metal coil spring (and the upperbody assembly) provides greater treadle travel and, therefore,provides the driver with a less sensitive "feel" whenmaking a brake application. The E-10™ dual brake valve isgenerally used on buses, where smooth brake applicationscontribute to passenger comfort."

So, the question is which one is suppose to be on your bus? I'll try to look that up later. Before I do, Joe probably has the answer.

[Joe Camper]

Ive never replaced one Gill. Every now and then air will leak out the exhaust port that is located on the bottom of the valve up on the ceiling of the steering bay that fools many and has people replacing them because of it. If u ever hear leaking from there its almost for sure one of the 3 R12 brake relay valves.

Your description of the E10 characteristics could explain both questions. First my thoughts on engagement of antilock on dry road. Maybe it can of u push that hard at speed. It would answer and also explain the soft pedal feel as well.

I've never had any truck or bus that needed this replaced.

[Ben Neumann]

Joe, it is the treadle valve and the new one is an E-10 like Gil is describing. The leak on the drive axle hub is on the inner seal. I took the big brake drum and seal to my local parts supplier for turning the drum. They are unable to do it locally and are shipping it to Sacramento, CA. I live about 50 Miles from Sac. half way between Sac. and South Lake Tahoe, CA.
Hope to get it back on Monday. The drum was very uneven and has hundreds of small heat cracks to the extent that I am worried it might be rejected for repair. The passenger side probably will look the same. When replacing the front bags I also noticed these fine cracks on the front rotors. I think I mentioned that I completely replaced the drivers tag axle brake rotor and brake pads. They were completely destroyed. I am hoping, when I get my brake drums back, that I will see an improvement. When you feel the inside of the drum, it feels very wavy inside. I also have to get new shoes for the one side because of the oil on the brake shoes.
The reason I am so concerned about the stoping power of this bus is, because I had an incident where I almost rear ended a young women in an TOYOTA . I was in Pomona,CA and was driving my Eagle Bus from one Freeway into the Hwy.10 headed for Palm Springs, CA. While trying to merge into the #10 from my on ramp I had the foot all away on the throttle and was looking over my left shoulder to merge. The traffic on the on ramp in front of me was moving freely and when I looked forward again, the traffic had competly stopped. I must have been going at approx. 45MPH and hit the brake as hard as possible. I got the bus to stop less then a foot from the TOYOTA. I ended with flat spots on all eight tires. If I had been in my Prevost at that time, I do not even want to think what the outcome would have been. I am alwys thinking about it and something tells me over and over again "my bus is not safe because of the brakes". I hope I never get in to a sitiuation like that again.
Ben

[Joe Camper]

I wouldnt turn a brake drum. Ever. I wouldnt buy brake components for prevo from anywhere than prevo. If u do not send the hub with the drum for turning there is the possibility it will run out when reattached to the hub.

If u do not like it replace it. When u turn a drum u have to use oversized brake linings. Don't like that either.

When u do the brake linings on prevo the linings and shoes and hardware, its all seporate. Lots of labor.

Im not saying u cant I'm saying experience has taught me different.

Small cracks in the brake drum r common, small cracks. Saturated linings can be dried out with brake parts cleaner with great results.

Did u index the bearing retaining nuts before u loosened them so u r sure it goes back togeather correctly?

I'm thinking your disc brakes r different on the steer and the tag. Correct?? I think your year is one that has the brakes on your 3 axles all configured different. Bremse front, drum drive, rockwell tag.

If u pull the front rotor it is knorr bremse unlike the tag that's rockwell. Be sure to locktight the mounting bolts for the caliper bracket on the front if u do.

There is a gasket that goes with the inner seal on the drive hub. Were those screws tight? That could have been the leak. Do u have the replacement gasket?

When reinstalling the axle be sure to tighten the studs with the cones first.

These vehicles r the safest things on the road but u cant drive them like a car. They r so smooth they lul u into a false sense of security. If u make that mistake it could cost u severely. Idiots who stop on freeway entrance ramps should have their lisence suspended, indefinitely.

[Joe Camper]

1409914100

This is the backside of a drive axle hub.

14101

Here is a shot of how the inner seal is designed on a prevo drive axle. This is different from truck stuff and most other hubs for that matter. On most the seal is pressed in directly to the hub. Prevo has chosen to add a another element with a flange and a gasket that is held in with Phillips screws that can come loose and make a leak. A common rookie mistake would be to reinstall the seal without first inserting the inner bearing. LOL

We have all done it.

[Ben Neumann]

Thank you Joe for your input. I have a different hub then the one you are showing on the pictures. I wished I knew how to post photos. Still something to learn for me. My hub does not have the small removable top peace like yours. It has a large encasing over the entire back part of the hub. I took a picture with my IPad. Also, when I removed the hub, I noticed, that the bearings had really been torqued down hard. I thought something like that should not have more then 50 foot pounds. It took some power to loosen it, but I do not know exactly how tight it was. I had no idea that it was important to know that. My old brake drums where made by Meritor and I am getting the exact same ones. I ordered them from my local parts house and will get them on Monday. I also ordered new brake shoes for both sides. These brake shoes are supposed to be a little bit different and I hope it will make a difference in braking power. At this time, I am thinking of removing the front wheels again and purchasing brand new brake rotors. Remember, I have a new rotor on my drivers side tag. I am also thinking of replacing the brake pads with the same type of lining I am getting on my drive axle.
I hope all of this will make the improvement I am hoping for. If it does't, I am really thinking of changing the front brake pods. I think they are #24 and replace them with 30th. This is just a thought at this time and I am not sure if it's even possible.
Currently I am stuck because I am out of parts and still need to replace the bags on the passenger side. The bag replacement on the drivers side is complete and it was an easy task. I will continue Tuesday, after I receive the new drums and brake pads.
Ben

[dale farley]

Ben,

This link will walk you through posting photos. If you have a problem, just let me know. http://forum.prevostownersgroup.com/showthread.php?6820-Picture-Post-Tutorial

[Joe Camper]

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I guarantee that u have the same hub. The only way they configured the drive axle hub for almost 20 yr that I'm aware of possibly longer.

I'm confused now because u have to have removed the dust cap. Its the only way u can get the leaky seal and then the inner bearing out. First remove the dust cover then the ring that holds the seal.

If u pulled the hub for leaking at the rear this is the only way to remove the seal that is causing the leak. If U did not pull the dust cap what was your plan of attack? How did U get the seal out. How u gonna put the new?

Another thing, u r not thinking correctly if u r even thinking about changing the front brake diaphragms from 24s to 30s. I do not even know they will fit and that's just unheard of. You would be wise to reconsider that.

14107

14108

14109

Many prevo hubs have the ring that keys the inner nut to the spindle but do not have the second washer that bends over the outer nut to also lock it. SO the outer nut has to be really tighted down vigorously or u run the risk of it getting loose. Once u free the outer nut the inner nut can or SHOULD be able to be turned off by hand. That is the critical adjustment going back together that should ave been noted before it was removed to either A verify it was either put on at the factory and correct OR installed later and wherever the prior mechanic put it at.

U do not put ANY torque on the inner nut much less 50lb. There should be 1\1000 to 5\1000 play in the hub if the inner nut is set correctly.

U better be carful it seems to me u r treading in deep waters.

I'd be very interested in learning where u sourced the brake shoe and linings for the drive axle as an assembly. If I had a chassis that the preformance of the brakes were in question and less than desirable I would not be going to outside sources for their replacement. Like I said earlier I never put brake components on prevo unless they come from prevo.

[Ben Neumann]

Joe, thank you again for posting the pictures of the hub. I just pried the old seal out of the hub without removing the dust cover just using two big screwdrivers. There was so much crust and oil on the back side of the hub that I did not see the screws holding the cover. I looked for it after I saw your pictures. You are right, my hub is identical to the pictures you posted. Getting the seal out without removal of the cover was pretty easy and took only a minute, but definitely the wrong way of doing it, but I will do it correct the next time when doing the passenger side and also installing the new seal into this hub. Thank you for correcting me. In regards of increasing the front brake cylinders on the front axle, that would be an extreme. I really have not checked this out at this time and it might not even be possible. Right now I am hoping that all the repairs will get satisfactory results. If not, I will go back to the front and one remaining side of the tag to change rotors and the pads.
Also, you are talking about purchasing parts from Prevost only. The drums I am replacing are made by Webb and so are the new ones. If they are not 100% identical, they are going back. The new lining is made by Apex and is supposed to be a little better then the old ones. I am hoping for some good results so that I do not have to think "extreme " again.
Ben

[Joe Camper]

We bought a pair recently a Coustomer did that is, and I installed them in Kokomo in. The pair were a dead on match. Not the linings though. That stuff was seporatly sent. Had to install with new brass hardware that is how prevo chooses to do it.

When u first put the hub back fill the hub with as much oil as u can before u put the outer bearing. Then get the first nut on. Rip it on as tight as u can turning the hub hitting it with a blunt hammer to seat everything. Then turn the nut back with the big axle nut socket and bar and feel till right at the point the nut frees up and then another inch AND STOP.

Next Turn it by hand back to tight JUST AND I MEAN JUST tight when it bottoms out again against the bearing. Dont snug it JUST bottomed out stop right there. Then back off 1 flat spot on the nut and insert washer/key. Got it? Has to be right? Do it a few times to get the feel I'm trying to convey. Then put the outer jam nut on and rip it tight. U see what happens when u tighten the outer nut is your taking back about half the slop u put in that inner nut when u turned it back 1 flat spot. Ahhhh yes.

Before putting the rims back on fill rearend very full and drop the jack on that hub as far as it will go and wait an hr or 2 to let oil migrate to the hub.

Getting the hub set perfect is not something u can explain over a wire. Its a feel that u get after a great deal of repetition.

When u take the other side apart do this. In fact before u reinstall the first one take the other side apart and do this. It will help u assure yourself they r both correct.

After u pulled the axle and got the jam nut and washer\key off STOP THERE.

Before doing anything with the inner nut grab it with your hand and see how far u can tighten it. BE GENTLE GO SLOW. If it was close u will be able to go approximately 1 flat spot of the nut till u feel it bottom out. Don't do any snugging just stop right as it hits you'll feel it if u go slow.

If that's the case what I tell the novice is to put it where it was 1flat spot back and mark the top of the inner nut and count the exposed threads on the spindle. That way wen it goes back together u will have the confidence of knowing its correct.

If u find it was too tight make it right if u had a real sloppy inner nut adjustment do it how I'm describing make it right.

Before pulling the inner nut grab it by hand and turn it to tight to check it before removal and be able to index things for yourself going back together, that's the ticket.

The amount of free I'm trying to help u get right is where I find hubs that I have disassembled and am sure have never been disassembled before and I've taken apart many such hubs and I always do this. That's where those inner nuts r set at the factory. 1 flat spot on the nut backed off from bottomed out and that would be without any snugging.

The next rally i get to we will do one and everybody who wants can get a feel. We will find a hub that's never been apart. Or we will go find a leaker and fix it in the demonstration.

[Ben Neumann]

Joe, thank you again for your extensive explanation on how to put the wheel back together. I sure appreciate all your time on this matter. I have not been able to work on the bus since last Friday, but I did get all the parts to start reassembly. Because the bus is leaning towards the passenger side and I am currently working on the drivers side, the rear axle lost about 3/4 gallon of oil. I knew I had to change brake shoes and the drum on that side also, but was unaware that the seal was also leaking. My question to you is the type and brand of gear oil I should use. I have no literature from Prevost about the bus. Tried to download some time ago without success, because it is no longer available.
Ben

[Gil_J]

Ben,

Here's what the owner's manual states:

"Multigrade gear oil meeting MIL-L-2105-D:85W140 is recommended for use in drive axle.This lubricant performs well over a broad temperaturerange, providing good gear and bearingprotection in a variety of climates.If temperature drops below 10ºF (-12ºC), 80W90should be used, and below -15ºF (-26ºC), 75W90should be used (in extreme conditions or for betterperformance, full synthetic gear oil can beused)."

(Click Here) (https://secure5.volvo.com/technicalpublications/pdf/pa1111-05.pdf) for the operator's manual.

[Joe Camper]

If it were mine and I did not know what is in there I'd drain it and put synthetic. It is so much better. The trans fluid too if u r not sure about that either.

Way mo better!

I'd be surprised if that is not what is in the rear end now but if u don't know, u gotta do the dirty deed .

[coreygrubb]

Joe, could you please call me 941 779 5018 or txt me your number. Talked to you recently and didn't write your no. down and now it's no longer in my phone. Thanks. George Prentice

[Ben Neumann]

Joe, I was unable to work on my bus because of other duties, but finally got going again two days ago.

I finished all air bags and put new inner seals and drums on the drive axle. In the meantime I ordered new rotors for the font brakes from Prevost because they show some bad heat cracks. The cracks are long and go from side to side on the rotor.
Today I started the removal of the rotor at the front. It took me 5 hours to get the bolts loose using my 3/4" impact wrench. It is an older one and has only 750 foot pounds of torque. I just order a new one with almost twice the power. Should have it some time next week. You were not kidding when you described the removal of the brake assembly being a real challenge. Had to tie a rope over the upper A-Arm to lower it to the floor. I removed the strange looking nut and rectangle washer from the hub assembly and thought I would be able to remove the bearing. Not so, I am unable to get it out. I am having a hard time understanding how to remove the bearing. It is the strangest thing I have ever seen. I know you said in your post to pull the hub. Are you doing this without removal of the bearing? If you could shed some light on this for me, it would be appreciated very much.
Ben

[Joe Camper]

I was wondering what happened to u.

Is it a pinch nut? I bet it is and going together will even be more fun. It is imparitive on these hubs with pinch nuts to index them before loosening them because there is a 1\16 of a lip on the backside of the washer going back together that doesn't just line up. If u don't it WILL tighten down and really have that correct feel BUT will not be right and will work away and out of adjustment. This is a very less than preferable design just too easy to get wrong in too critical a location. Pier did this.

On pinch nut spindles the nut when the entire hub assembly is correctly installed, that pinch nut is very close to flush u might see maybe 1 exposed thread of the spindle maybe not. With as many as I've done, knowing the goofy washer, I'll always still take a picture, index and make damn sure its right going back.

If u got the pinch nut off and the spacer out and the caliper bracket with its 6 gargantuan bolts removed the rotor has to be jiggled vigorously to come. Once u pop the outer bearing it al come.

If u can't post pictures u should take one of the pinch nut and both sides of the flat washer send them to me and I will post them and explain what's going on and how to reinstall it would be very helpful. Some quite experienced mechanics may never even encounter a pinch nut on a spindle in their entire career. Thats how uncommon. Then they complicate it further with the design of the washer, a design thing that's so slight, crazy design lol. Good stuff.

Also, was the black plastic dust boot on the larger caliper slide pin trashed and the pin rusted or was that in tact?? Either way I have some tips on reassembling those calipers with the replacement slide pin kits that we should go over before u do.

The sensor for the antilock is another thing u have to note going back together it can quite easily get knocked out of adjustment without knowing it when u have pulled the hub.

Shoot me some pictures. 708-243-7871 this is my cell.

Good to hear from u again. Proceed slowly everything your working on is quite critical. Its not something I'm passing over the interweb that I'm totally comfortable with going to someone i am unaware of their aptitude. I would assume u have the same thoughts about me, u should.

[Joe Camper]

The way I get those 6 caliper bracket bolts off is this.

I use a short 6point impact socket with a 3/4 in t bar that I slide a tight fitting cheater pipe over. Then depending on the specific location (some will loosen going up and that's when the floor jack works. Some loosen down then another bar and leverage works.)

I either slide a floor jack under the cheater pipe and jack it loose for the ones that loosen up or use another long bar, horizontal to the cheater, with its end up against a housing member creating as much leverage as nessessary by pushing down on those that loosen that way.

Do not be disappointed if your new tool is still insufficient to free them. It would not be the tool thats defective. May the force be with u.

BE VERY VERY CARFUL WHEN USING CHEATER BARS.

The bolt is still going to require a huge amount of force to get started loose and if any thing slips loose it the event of trying u can really hurt yourself bad in a whole variety of fashons. Make sure your noggin is nowhere in the line of fire.

Maybe your new tool will get them I hope it does.

[Joe Camper]

Ok the pinch nut.

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Before I go further I would like to find out if anyone has ever seen a spindle/axle nut on a auto or truck of this design. I have not. On some larger equipment or farm implement possibly but even there I have not.

Someone school me here what other manufacturers and apparatus other than prevo incorporate this design.

Pinch nuts attached to shafts I've seen, that doesn't apply. On a spindle nut on an axle is completely foreign to me. I love it. If they'd have lost the ridiculously sutle complication in design for the accompanying washer its a very clever idea IMHO

They only did this on the very early IFS. First time I opened one up was 1000 miles from home in a gravel lot never forget it. 99 degrees no shade. Sawdust, Raleigh Durham.

Repeating myself purposely this chassis is with different brakes every axle. Knor bremse steer axle, drum drive axle and Rockwell disc tag. I've also been told by a reliable source the steer axles with the pinch bolts r fired in England. There quite a few of them out there.

There is still quite a bit of this thread to come, going back together thats the pickle.

[Ben Neumann]

Joe, thank you again for your input and phone call yesterday. After I talked to you, I went back to the project and within about five minutes I had the bearing out and the hub and rotor on the floor. At that time I also noticed (which I never noticed before) that the front brakes don't have the conventional slack adjusters. I found the adjustment srew on the caliper but can't figure out how the automatic adjustment works.
I have not done any other work besides just taking the hub off. Today I need to work on my daughters new house and might get back to the bus some time in the middle of the week. Will keep you posted.
Ben

[Joe Camper]

No slack adjusters????? Oh no Mr Bill how could it be?? Its magic!!

Just kidding. I'm a firm believer in these knor bremse brakes. Noticed lot of fire truck chassis also use them whatever that's worth.

Thats Great news.

OK I have resurrected a knore bremse brake thread that contains everything in regard to the brakes. It will explain the adjuster along with everything else. Go read through that.

I have someone checking the prevo service manuals for me so I can be absolutely sure the info regarding the pinch nut is spot on.

He has an extra prevo service manual for your vintage if u would like it he said 50 bucks that's a deal u should have it. He used to be a pogger, Lonesome George. Lemeno I'll hook u up and post the correct reassembly of the pinch nut and corresponding washer.

In the meantime read through the brake thread I've pulled up.

[Ben Neumann]

Thank you Joe, it will be great having the Manuel. When he is ready to ship, please have him email for payment and shipping address. berndgehrkeneumann@gmail.com. I am going to look for the article on the slack adjusters.
Ben

[Joe Camper]

OK Ben I checked with some friends and then put in a call to prevo to double check on torque spec for reassembly with knore bremse brakes.

This is good stuff so I hope there r others out there that can laugh at this stuff.

In the manual they refer to the six large bolts that hold the caliper bracket on "caliper set screws" LOL

In the manual they refer to the long caliper slide pin bolts "caliper bracket nut"

In the manual they refer to the pinch nut as "pinch bolt" LOL

In any event here r all the correct torque numbers

Pinch nut would be set 1\2 of 1\1000th to 2\1000ths from just touching snug. Its bolt that squeezes it 25 ft lb

The 6 large caliper bracket bolts 325 to 350 ft lb and the prevo tech assured me and convinced me to go to blue locktight it is a better solution to the red originally used. Those SOBs r so so hard to crack loose with the red on
them.........

The 2 long caliper slide pin bolts r 85 to 105 ft lb. They come with blue locktight already on them.

After me and lonesome couldn't bang our heads together on the definition and terms used in the manual I decided to call prevo to make sure and these numbers have been confirmed.

So the pinch nut thats no more than 2\1000ths here is what that means to a grease monkey. Let's go over that.

The rotor and hub is massive and heavy. Get it on a sturdy cart on a smooth surface and using 2 stacks of wood line it all up just outside the spindle. Take your time block it so it sits lined up without having to hold it and get it perfect to just a shim low if your off not higher. Then grease the inner bearing and the seal and the spindle. If the bus gods r helping u it will push up and far enough to put the washer up and thread up the punch nut.

2 things here that r figity and a fuss. first the washer needs to be physically centered as u run up the pinch nut to it. If u don't u will trap the washer between the nut and a flange in the spindle where the threads end. This is s very easy mistake to make and don't progress until u get a feel for that and u know its centered. Its a very slight lip and slight difference in feel between centered or not.

Secondly the pinch nut is round and u can't just put a socket on it when your reassembling like any other hub with a regular nut where u can ripp it very tight initially turning the hub before backing it off to the right spot to assure the hub is seated.

U can't do that easily with that round nut. So use rubber gloves and if u grab it real hard u can turn it down far and hard enough while turning the hub to get the hub totally bottomed out so when u back the pinch nut back to right at the point where its just touching or that magic spot. Then I'd turn the nut counter clockwise 1in at its outer diamiter and lock it down. Then that will set right and not change going forward.

Hub cap gasket oil. The 8mm caliper adjuster on the back of the caliper, after u put the linings in tighten the caliper till its clamped to the rotor and 1 click back. Put silicone on the clip retainer.

1 other thing is the abs sensor. Its adjustment can be changed if it gets bumped. In fact that's how u adjust the sensors by tapping them closer or further. U can very easily bump them without knowing it when pulling the massive hubs. After u put the hub up if u don't have the book be sure the wheel sensor on the side your Woking on is the same as the hub on the other side. Its moved with very slight blows with a punch and hammer.

[Ben Neumann]

Thank you Joe, just read your post after I tried this afternoon to reinstall the front wheel hub and rotor. I am exhausted and totally frustrated because I was unable to slide the hub on to the spindle. I even separated the rotor from the spindle and was able one time to slide just the hub by itself without the rotor on to the spindle. Apparently the tolerances between spindle and bearing are so tight, that the slightest disalignement binds the bearing on the spindle. At this time I am wondering if I should use a little bit of force and use a block of wood and a hammer to get the bearing on to the spindle. I am reluctant doing this and make a mistake by jamming the bearing on to the spindle.
At your post you are describing how to do it. I wished I had read your post first before I started. I used a large floor jack instead of the wood. I think I had it lined up pretty good and under normal condition it should have slipped right on. I never thought I would have a problem getting the hub back on, I thought the difficulty would have been to lift the caliper back on to the wheel and get the bolts back installed. Going to give it another try tomorrow morning.
Ben

[Ben Neumann]

Joe, today on Saturday I made my second attempt to install the hub and rotor. I got it done. What I did was take the rotor off the hub and lifted it on top of a floor jack and then adjusting it to to proper height on the spindle. I tied it with a wire to the upper a-arm to hold it. Then I cleaned the spindle and the inside of the bearing, removing any oil. Got the grease gun and covered the spindle and inside collar of bearing with all-purpose grease. Now I took the hub and it almost went effortless on to the spindle. Moved the rotor close to the hub and inserted and tightened all bolts. By keeping the rotor and hub separated, I was able to preform the task by myself. Installed the large washer and nut per you instructions. I think I got it right. I prepared the caliper for installation and cleaned and lubed the shafts. I did not have time to call for the repair kit as per your advise. Will do so in the spring time when it will be easier to work outside. This afternoon I will try to get the caliper installed. Need to make a jig on top of my floor jack to lift this monster. I think the hub by itself weighs close to 90 lbs. The rotor is about the same, but the caliper is approx.100 lbs. Just a guess. Will keep you up.
Ben

[Joe Camper]

Good job. U were fortunate to be able to separate the hub and rotor because the alen heads get so corroded u can't loosen them without stripping the head. If u put good silicone in the alen heads it will keep them from corroding further and u will get them apart next time too.

Be sure to check the gap on the wheel sensor for the antilock.

Be sure to refill the hub a second and third time waiting a few hours each time.

U could remove the brake chamber from the caliper with 2 nuts that would make it lighter a little.

U give me hope that I will be able to continue doing this about a decade longer than I thought that any reasonably healthy guy could.

That stuff is heavy but im not sure its that heavy LOL in any event U r amazing.

[Ben Neumann]

Joe I was worried you were froze in. I am watching the news about the cold in the Midwest and East. Even here in Northern California it is unusually cold. At my place (3100' high) it got down to 26 degree)
Yesterday afternoon I tried to install the caliper but failed to do so. Was just too heavy for me and I injured my right arm a few days ago. I lifted it with my floor jack as high as possible inside the wheel well and secured it with a rope to the upper a-arm. Had to wait for my son in law (who is a big guy) to move the unit from the jack over to the wheel. Will install the bolts this morning and using the blue lock tied as you suggested.
The bolts fastening the hub to the rotor on my bus are not allen screws. They used 22 mm hex bolts. Was easy to get them off. I got my new 3/4" impact. Can't believe the power it has and it is a light weight unit. Thanks for the advice how to lube the wheel. I will go back this morning and finish this wheel and hope to start disassembling the passenger side wheel. I again will not have any time to continue working the project before Thursday or Friday. Will keep you up.
Ben

[Joe Camper]

As different and as figity and physical all this is, compared to ......, If there is any 1 thing that needs stress is getting the pinch nut set perfect.

When u do the other side before loosening Index that slot in the nut and count the exposed threads and be sure what the backside of the washer is. I'll feel a lot better if u promise.

Look at the gap for the antilock sensor beforehand in case u bump it.

Back the caliper out all the way before u pull it out. Count the clicks and see how much pad u have used and have left.

It is a beautiful sunny day in Chicago. Current weather is a 10 mph wind, 9 degree noon time temp dropping to 10 below for an overnight low.

[Ben Neumann]

Followed your instructions and also took a close-up pictures of the pinch nut. Counted the revolutions it took to get the nut off. There was a center punch mark on the spindle and it took exactly 10 1/2 turns to get the nut off. I got as far as dropping the caliper to the floor. I again tied a rope over the upper a-arm and lowered it down. My new 3/4" impact gun preformed fantastic. It is an "Air Cat" and has 1400 foot pounds of tork and is light weight. I am surprised that such a lightweight gun can produce such a brutal force. I think I paid $290.00 at amazon. It ripped those large bolts loose in the lowest power setting. What a difference when you have done the job once before. Did not have to experiment any more. Took more pictures and wrote myself some notes. Hopefully I will continue my work on the bus on Thursday. Need to get back to work repairing my daughters and her husbands new house. It is a fixer-upper.
Ben

[Ben Neumann]

Joe, a few days ago I contacted George and purchased the repair Manual. Nice fellow and very knowledgeable about the Prevost Bus.
Yesterday afternoon I finally had time to finish my work assembling the wheel and brake assembly. It sure makes a difference if you have done it once before. Took me no time to get the job done. This time I lubed the spindle and the inside of the wheel bearing of the hub with some moly grease. Worked great and the hub went on effortlessly. Will finish up installing the oil hub and filling it with oil. Also need to go back to the rear and fill the drive axle with oil. It will be exciting taking the bus on a test drive to test the brakes. I hope the work I did will lead to a major improvement to the overall braking capacity. I was asking George if he knew if there are any pressure regulating valves between the E10 foot valve and the wheels. In other words,"if you step on the brake is there any air pressure reduction between any of the wheel brake chambers and the E10? He said he did not know but also said he did not think there was. I would like to ask the same question to you.
Ben

[Joe Camper]

Im not sure exactly what your looking for.

On any air brake chassis the air that is being delivered from the brake pedal is a signal that goes to a brake relay valve. The relay then provides air to the brake chamber directly from the air tank. The air tanks and relays will always be as close to the axle as physically possible. This design eliminates fade and delay. Otherwise axles further would engage and release slower than axles closer to the brake pedal.

So yes there is defiantly components between the pedal and the chambers, the brake relays and the antilock valves too.

In actuality the air coming from the brake pedal TERMINATES at the brake relay valves and it does not even go to the chambers. That air is supplied directly from the air tank by and through the relay.

[Gil_J]

Ben,

I think I've been through every component in the braking system. I know of no proportioning valves or air reduction valves.

As Joe said, their are only air control lines from the brake pedal to the relay valves, with one exception. The control air for the tag brakes has to flow through the inversion valve.

The best I can determine brake capacity is a function of the brake pads/shoes, discs/drums, and brake chambers. The brake chamber determines maximum braking pressure. If you have ABS, it's pressure regulators are in the high volume lines going to the chambers.

I would assume the only test would be to measure the air pressure being delivered to each brake chamber. If a relay is obstructing air flow, which would seem remote, it will affect all downstream brake chambers equally.

I will say I'm still trying to fully understand the spring brake relay. It should only be activated by low pressure or manually pulling the push pull handle. With that said, it is also plumbed to the front and rear brake systems. One connection is off the treadle valve.

[Joe Camper]

The relays r proportionate in relation to the amout of pressure applied to the pedal.

[Ben Neumann]

Have not responded to your threads before Chrismas. Have been busy with lot of family duties and had limited time to worry about the bus. But I got it all finished and took it for my first ride. Went from Northern California to the FMCA rally in Indio in Southern California. I am currently in Quarzside AZ. The brakes feel completely different, but at this time I have not made a hard braking attempt. Will do that next week on my return home. It looks like my repair has been successful. In city traffic, I definitely use less pedal pressure to stop the bus. But I will know for sure next week and will let you know how it went.
At this time I would like to thank you guys for helping and especially Joe for spending so much time with me to get me on the right track. Thank you again.
Ben

[Gil_J]

Ben,

It is always gratifying when members help others. Joe is definitely the goto guy when it comes to suspension and braking systems.

[Ben Neumann]

To Joe and Gil,
After driving close to 4000 Miles after the repair of my brakes, I am now able to make an analysis of my brake repair job. There is no comparison what the brakes are like now compared to before the repair. By applying light pressure to the pedal, I now notice how the front of the bus moves downwards a little because the front brakes are catching on. I never had this before, when braking, there was never the downward move of the bus. I feel a lot safer now when driving in heavy traffic like I just experienced in LA and Phoenix.
Again, the repair was sucesfull. I would like to thank Joe and Gil taking the time to help. I would especially thank Joe for taking so much time to go into details to explain and guide me through this job. My advise to anyone else who might get help from Joe: Pay attention to the small details he might be describing, because that is were the quality of the job will be. Thank you again Joe and Gil.
Ben

[Gil_J]

Ben,

Great news! I think you have proven that pads build up a glaze reducing their friction with the disc or drum. Just because plenty of pad is still there doesn't mean they still stop like new pads.

BTW, we both know the thanks all goes to Joe. Joe is definitely the under carriage guru.

[Joe Camper]

That's great news. There was a boatload of stuff we went through and doing it over the interweb.

It's been quite a while u had me nervous.

I think if there were 2 big points it's the washer behind the pinch bolt spindle nut and a good solution for getting the hubs back on the spindle then making sure it's as it was before disassembly.

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And here is a painless way to replace that massive hub and rotor without nicking the new seal.