Specifications

Air Bags
Air bags are an interesting item to folks with this chassis. Leaks can be located by removing the
bag from the vehicle, inflating it and submerging it – just like looking for a tire leak. Actually, if
it doesn't hold pressure, you have a leak. The logical repair is a replacement. If you replace,
replace bags as a pair.
There are basic guidelines for inflation depending on which version of the P Chassis you have.
The air pressure should never be under 10 PSI unless you are removing/replacing the airbag.
Air Bags Front:
For a 4,300-lb suspension, 40-50 PSI.
For a 5,000-lb suspension, 50 PSI.
For a 5,300-lb suspension, 70 PSI.
For a 5,500-lb suspension, 90 PSI.
The GM part number is 367762 for the bags used in the 4,300 and 5,000-lb suspensions.
The GM part number is 15631881 for the bags used in the 5,300 and 5,500-lb suspensions. This
is an Airlift H.D. Bag. The part numbers can be updated at any time, and a new part number of
15731951 was released for 1984 through 1997, but your handy GM dealer should be able to
figure it out. Be aware that these front air bags are contributors to the GAWR (Gross Axle
Weight Rating) for the chassis. Underinflation actually will decrease the rating and will
undoubtedly affect handling. Overinflation makes the ride harder and doesn't increase the
rating.
REAR:
I've seen air bags on the rear of a Winnebago Warrior ... but don't know if these were installed
by Winnebago or a previous owner. These seem to be installed by after-market suppliers to
cure sagging rear spring problems. There is no reason to believe they can be used in the rear to
cure overweight problems unless other items in the rear suspension are also beefed up. I can
find no reference in the P Chassis manuals that say they are installed by Chevrolet. Tag axles
added by a coach manufacturer sometimes use air bags instead of springs. You have to get the
inflation spec from the manufacturer. Except for the tag axles, if the class A you just purchased
has rear air bags, chances are they were installed as an after-market fix by a previous owner. The
good objective for having them would be for the empty coach to sit level with almost empty
rear air bags, and then inflate to compensate for various loading configurations up to whatever
max the airbag manufacturer has specified.
If you are inflating any airbags to compensate for out-of-level problems, it might be worthwhile
to consider replacing the coil springs in front and/or getting new or re-arched springs for the
rear. Think in terms of the age of your motorhome. Springs do have a limit to their life. The
http://users.sisna.com/cebula/P-Chassis-AlignmentProcess.pdf 10 Version 0.7 –Sep 14, 2005