Doesn't sound like something you can easily determine? Take it to a mechanic you trust.
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 really
add much to the rating.
REAR:
Rear air bags are NOT part of the original chassis as supplied by Chevrolet. They are either
added by the coach manufacturer or 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. Tag axles
added by a coach manufacturer generally use air bags instead of springs. You need to get the
inflation specs from the manufacturer. The good objective for having them as an add-on
AFTER the coach was manufactured, 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 'ride height' check we will do in a bit and the charts in Appendix A and B will
help with this determination. As one of the improvements, new springs can be exactly
Main Body Page 6 of 38 Total Pages
