Several years ago the King and I decided to change all the air bags on our coaches. The incentive was that Roger wanted to change them, but Prevost had shipped the wrong front air bags.

I ordered both sets for our coaches, but in doing so I found the Prevost parts folks in Elgin had a high potential to ship the wrong air bags. I spent quite a while with the parts guy until we both agreed on the proper air bags for Roger's coach and mine. Specifically we got 630126 air bags for the front axle of our coaches (now superceded by 630259) and not the air bags listed on the bill of material. The air bags listed appeared to be for a seated coach, the significance of which is important.

Our motorhome shells are designed to have about 4" of both up and down travel from ride height. The purpose is to allow leveling on uneven campsites. A seated coach is designed to go down (kneel), but not be raised above normal ride height. It is likely that anyone that orders air bags for their coach or has them replaced by Prevost is not going to get airbags the equivalent of what was on the coach when it was built. Prevost continues to ship and install the wrong airbags on motorhome coaches.

This is a critical piece of information that everyone should know and understand. If you are going to have air bags for your coach replaced there are some things you should do. First, measure the ride height, the lowered height and the maximum raised height of your coach. The proper way is to measure the distance between the upper and lower air bag mounting plates, but it is just as easy and understandable to measure from the bottom of the bay door just behind the front wheel to the floor surface. When having the air bags replaced be certain that the installer understands you need to retain the amount of travel you have, and that if you do not get that travel with new air bags they need to be replaced with those that will provide the travel.

There are other issues related to this that all of you should know. First, the current air bags being supplied have larger fittings for the air supply, and the top mounting plates on some coaches do not have a hole large enough to accomodate the fitting. The hole in the top mounting plate in that case may need to be bored or torched out to a larger diameter to accomodate the fitting in the top of the air bag. Another issue is travel. While it is important to retain the amount of vertical rise above ride height, it is equally important to not have an air bag that will provide more travel. It is possible to break the top mounting ring from a shock absorber if there is too much air bag travel. A broken shock absorber can do some damage so it is important to not install airbags that can break the shocks.

There are some coach owners who now have air bags on their coaches which do not allow any travel above normal ride height. If this is not a concern it should be. Because we take our motorhomes into some campgrounds that are not as flat or level as the streets a seated coach will encounter, we may have to raise the front above normal height so the front of the bus does not scrape the ground. If we have to be put on a flat bed trailer we may need the extra height to prevent damage to the front. If we have to clear a hump to prevent damage to a low hanging generator baffle we may have to raise the front. These reasons go beyond leveling the coach at a campsite.

I do not know specifically if this situation exists with H3 or XL coaches with IFS, but it could so be alert and take the same precautions if air bags have to be changed.

If you allow yourselves to become a victim of reduced height due to the wrong airbags remember Prevost will not correct the problem. To their way of thinking the air bags they list and install are what is called for in their parts lists and they will not do anything to correct this so it is up to you to get an understanding from Prevost up front as to what you expect after air bags are replaced. It may not seem like a big deal now, but if you damage the lower front of your coach or wipe out a generator baffle because you cannot raise your coach up this issue will take on a greater significance.