[Richard]

Let’s look at the Firestone bag construction difference.

The first pic shows the bottom support ring. Note the bolt in the center.    

The second pic shows the bottom support ring removed. Note how the bellows rubber is molded around the base of the piston and actually comes up over the top (bottom) of the piston.    

A closeup of the bottom of the piston. Remember the support ring is bolted in place and you can see how it captures the bellows preventing it from breaking it’s seal on the piston.    

Back to the real reason for this post. When I did the brake job last fall, the suspension was raised at full height for almost two months, thanks Covid. During that time the tag bags and the rear drive bags developed leaks. The suspension would not stay up while parked for more than a few hours. My first solution was to order all Firestone bags and fix this problem once and for all. Well the Firestone bags still in production are on indefinite back order. I waited 5 months the last time I bought Firestone bags on back order. And as I stated earlier the tag bags are obsolete. There may be an in production bag that will work, but those numbers belong in the air bag identification post.

So what is a redneck to do with a known leaks in the bags, at known locations. Option one was to remove them, inflate them with an air compressor, and reinstall. That is a lot of work. So, I cheated. I removed the inlet air lines to the bags and pumped about a quart of Slime into each one. Bingo !!!!!!! The coach is maintaining position and the whole operation took less than two hours. My guess is that the Slime provided some lubrication that allowed the bag to slip back into place around the piston, and it then sealed up any of the smaller leaks.