Front wheel removal of 1998 Prevost XL

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

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.

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

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.

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.

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.

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

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.

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.

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