[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.

[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.

[encantotom]

richard, my experience was when i replace the old goodyear tag bag with a new goodyear (on my previous 99), the new one had a completely different design that i believe would not allow the burping.

tom

[ccjohnson]

Are you concerned at all about the Slime migrating out of the air bag into other areas of the air suspension system?

[Richard]

Not at all. Since it is a heavy gelatinous material, it will settle to the bottom. Even with heavy discharge from the bags, remembering all exit air has to exit through a 1/4 hole in the back of the six pack, there is no driving force to lift the liquid 8 inches to the discharge of the bag.

If it were a powdery substance, I would be concerned about migration.

I choose slime on purpose for it’s long term compatibility with rubber, and anti corrosion additives for steel. I didn’t want to rust through the metal piston in the air bag.

It’s not an ideal solution, and I continue to research to find a suitable Firestone replacement bag for the tag axle. I posted this redneck hack to potentially help someone in a pinch with a leaking air bag. It is not a substitute for replacing an old or damaged bag.

[Richard]

Our good friend Tom has made me aware that the design on the tag bag made by goodyear has changed. And he was gracious enough to send me a picture of 1r11-202. This very good news. However, the bags for the drive axle are still showing the old design in the Goodyear catalog. 


       

[bikestuff]

Gurus,

A wise professor once told me that “A word to the wise is sufficient”.   Richard’s post is that word.  

I have been plagued by this issue for 10 years. I have swapped out more air bags than I can count. If the coach is warm and sitting level...the bags will hold air...but if I am at any angle at all....the bags will leak down.  Previous posts in this thread explain why the leaks occur.   Swapping to Firestone or the new design Goodyears is really the only answer for our vintage coaches.  This picture shows how much movement the bags on our coaches endure....no wonder they leak.    

During the recent cold snap, one of my two-year-old Goodyear bags would not seal no matter what I did.  I limped over to a truckstop and their tech worked on the bag for five hours before he was able to get the airline off.  We threw in a quart bottle of Slime.  Between the Slime and sitting in a fairly warm shop for a few hours...the bag finally sealed up and I was on my way.  If I had carried a set of claw foot wrenches...the swap out could have been done in an hour.   I will from now on.      

Yesterday, I received 2 Firestone drive bags which will complete my swap out.  I hopefully will not find myself stranded again due to an airbag issue.

[Bigbertha]

Guru's,
How many air bags are there? I had the right side of my coach go down about 2 weeks ago on my way back from NY.
I was getting fuel and the entrance wasn't level so the coach leaned a little too much, I fueled up and drove a couple blocks
fearing I was broke down for the night in 3 degree weather. The coach started to level out and it was up at normal height
in about 5 minutes. I was able to drive another 200 miles and made it back home to St Louis.

After reading the post yesterday and looking at the 10 pictures of the air bags I'm guessing I probably have the Goodyear air bags, looking at picture 10 I'm thinking it pulled up and released the air and then went back down and resealed itself.
The last thing I want to do is be stranded in the middle of nowhere, do you feel it's a good idea to replace the air bags with the Firestone and what's the approximate cost to do it? Thoughts?
Thank You
Dale

[Richard]

You have four drive axle air bags, and two tag axle air bags. Approximate cost is 1200 bucks or less for the six air bags in the rear. Installation costs will vary on who does the work.

No doubt that the cold weather makes this issue more prevalent.

I cannot tell you what to do. I am replacing all six Goodyear bags with Firestones. My Goodyears are less than 4 yrs old. For me it’s a nuisance problem, but I had rather work on the coach at my place in Florida, than work on it in the middle of Wyoming.

[bikestuff]

Gurus,

Dale’s experience mirrors mine and other gurus. He instinctively did the right thing. In normal times, the coach and bags will do the right thing....but sometimes...especially in cold weather...the bag does not have the flexibility to pop back nto the correct sealed position.

If this happens to me...here is what I try....YMMV

1. Get the coach into a level place where you can idle safely for a few minutes.
2. Use the distance between the mud flaps and the ground as an easy way of seeing if you are leaning.
3. Use the leveling system to dump all the air out of the bags.
4. Once the air is all out the coach should be sitting level. (If not you have a different problem)
5. Go back to travel mode and put the engine on High Idle to re-flate the bags.
6. When the coach is back to travel height, verify that it is sitting level by looking at the mud flaps.

If this does not work... try steps 3-6 again.

Note: For some coaches the body will set down on the wheels and make driving impossible. For my coach, the coach stays high enough that I can limp along even with the air dumped from the bags.