[Richard]

This topic has been covered in other threads about air bags, but usually hidden in within threads. 

On coaches with Ridewell rear suspensions, Goodyear air bags made in the last five years, maybe longer, have a known design feature that does not play well with the Ridewell suspension. It is at it’s worst with the tag air bag. 

Let me describe the problem and then illustrate with pictures. If you look at the Ridewell suspension it pivots at one end, and the air bag is located at the other end, away from the pivot. The air bag is captured at both top and bottom. The top is bolted to the frame, and the bottom is bolted to the suspension. As you raise the coach above travel height and the suspension pivots, the two surfaces that the airbag is bolted to obviously move apart. They also do not maintain parallel alignment. On the tag in the fully up position, the two mounting plates are about 20 degrees out of parallel.  On Goodyear air bags that is sometimes enough to cause the air bag to leak or burp. If it burps, the suspension will sit flat down with a big whoosh. If it just leaks, the suspension will slowly settle out of level. They may or they may not reseal themselves if you let the suspension all the way down. I have seen the leaking with my coach, I have seen the burping with Bill Johnsons coach where it sat completely down on one side in less than a minute, and I know that Mike Ginn’ s coach did this on the freeway putting the fender on the tires while moving. 

First, the pictures of the Goodyear bags show how this is possible. 

In this picture you see assembly of the bottom of the bag.    

In this picture you see the support ring, which is not secured in any way, removed.    

In this picture you also see the metal piston protruding from the bottom of the bag, you also see the bolt that secures the piston to the suspension. 

In the last picture you see that the piston is simply sealed to the bellows of the bag by the piston fitting tightly into a reinforced bead molded into the rubber bellow. That is the root cause of the problem    


When the piston is cocked in that reinforced ring (think tire bead), it breaks the seal. The piston cocks when the bottom and top plates are not in parallel. 

Oh my, now that you have given me one more thing to worry about, is there a solution? Yes and No. Firestone air bags are constructed in such a way to prevent this from happening. Great, yes except two things. The bags we use for the drive axle are special order and take forever to get. Plus the bag we need for the tag is obsolete.