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Air bag replacement

When should you replace your suspension air bags?  Mine are showing minor checking along the bottom flex point, and I'm not sure how much minor cracking is too much.  Coach is 1996 40' U320.  Bags look to be original.

Re: Air bag replacement

Reply #1 –
 I doubt that you need to touch them yet as the inner wall is quite thick. Mine are showing similar traits but not bothering with them for a couple years.
JohnH

Re: Air bag replacement

Reply #2 –
John,

Minor checking/cracks no problem. The bags are two ply with "fabric between".

Are we tired of our diesel baths yet-- yes private joke (both of us were replacing fuel lines today). Eau de diesel may require a half hour in the bay.

Brett

Re: Air bag replacement

Reply #3 –
For a while there I was passing tools to Martine who was sitting on top the engine--- she spent half hour in the shower when we got home, and still no new fuel lines installed. What a PITA job!  We did get the generator fuel leak fixed however.  Many thanks for your advice and council!

Re: Air bag replacement

Reply #4 –
I'm considering buying a couple of spares and keeping them in the storage bay just in case.  I carry a air over hydraulic 20 ton jack in the bay also and 14.5" chassis blocks to safely work with the air bags blocked up.  I tried the "raise" function on the leveling system this afternoon--- it did strange things.  I pressed "raise" and the bow went to full down while the stern went to max height.  Then everything went back to "travel".
Ghost in the machine.

Re: Air bag replacement

Reply #5 –
Here is our air bag replacement story:
Air Bags Replaced - 1997 U270

Front two bags on our coach are a major problem to replace, but the others will go much easier.

All air bag bolts between frame and front & rear bulkheads are very hard to reach and 18 year old nuts can be quite stubborn. Consider periodic Nut Buster spraying as insurance.

Re: Air bag replacement

Reply #6 –
Quote from: Kemahjohn –
  I pressed "raise" and the bow went to full down while the stern went to max height.  Then everything went back to "travel".
Ghost in the machine.

OK, John, we need to quit with the boat directional references-- Dianne and I still do it on our coach as well. Luckily, she still knows where to put the wrench when I say AFT of the PORT front wheel.

Re: Air bag replacement

Reply #7 –
Once a sailor, always a sailor!  When I truely retire, I'm going to walk away from the coast with two oars on my shoulder--- when I get to where someone says "what are those?" I'll know that is where I'm supposed to settle down.

Re: Air bag replacement

Reply #8 –
Barry,
Excellent pics!  Based on how yours looked, I think mine are good for a few more years--- they don't look nearly as bad as your old ones did.  Just some minor checking cracks.
I was concerned because they looked worse than my 1990 U280.  I suppose that the previous owner had already changed the bags on it.  They look great.

Re: Air bag replacement

Reply #9 –
A white kitty litter container holds a spare airbag well. Makes it easy to store for a leaky day.

Pierce

Re: Air bag replacement

Reply #10 –
I replaced mine about a year or two ago just for the peace of mind that i would not have a problem when on a trip.  Enough rubber had come off so that I could see some cord.  Truckers do have air springs blow out occasionally and I know at least one owner had a leak in a bag wall.  If the leak is small the compressor can probably keep the bag inflated while driving.  If you don't replace all at the same time, best to replace the rear as they carry the most weight.  The nut on the hollow bolt for the air is a pain; fine threads and lots of turns to get it on and off.  I removed the rear fenders to make the job easier, but I think it is possible to change them without doing that.  I think I did the front with the fenders on.   

Re: Air bag replacement

Reply #11 –
FOT replaced air bags for us in January 2013. Bags were original on a coach manufactured in November, 1996. One bag started leaking while the coach was in a bay at FOT undergoing replacement of fuel lines. Rubber on the exterior was flaking off in 2010 when we bought the coach. Some fabric cords were showing well before the leak started.

Based on my experience and some knowledge of the experience of friends, life of the bags installed in the late '90s coaches appears to be about 16 years (+-2) if there has been no mechanical damage to them. Fuel lines and air bags seem to become unreliable about the same time. Of course, your experience may be different.

Re: Air bag replacement

Reply #12 –
My experience is similar to J.D.'s.  IMO you're living on borrowed time.  Better to replace them all now than being stuck on the side of the road.

Re: Air bag replacement

Reply #13 –
I replaced all mine on my 95. One developed a leak.
They can look OK but, When you remove them and pull back the rubber you CAN'T see when installed,you can then see how bad they really are.

If original I would replace.

I removed the front fenders and it was not a bad job. The rears i did with the fenders on.

Re: Air bag replacement

Reply #14 –
I just had all of mine replaced, the rubber was starting to flake off the outer covering and a couple of them had a little cord showing. Before the replacement the coach would re-level itself every couple of days, now it remains level and I never hear the compressor run.

Re: Air bag replacement

Reply #15 –
The leak down rate on my coach is very slow--- it takes up to a week to leak all the way down, and the air bags remain mostly inflated.  The left rear is a little less inflated, but could be the height valve.
 

Re: Air bag replacement

Reply #16 –
Quote from: Kemahjohn –
The leak down rate on my coach is very slow--- it takes up to a week to leak all the way down, and the air bags remain mostly inflated.  The left rear is a little less inflated, but could be the height valve.

I thought I might be having problems with leveling solenoids or some other six-pack issue while we were up in the UP. Had a pair and went to the local RV place. They discovered a leak in an aft bag. I ordered a full set (funny store about delivery - see Air Bag shipment story (split from Leveling Issues)). Replaced 4 rear there in UP and fronts at FOT when in for Spring donation time.

Now the air in the tanks eventually leak out but the air in the bags (and hence the coach level) doesn't move at all.

I think gravel gets thrown up into the lower part of the bag where it folds down and wears there.
See Air Bag Replacement Cost (maybe) for costs and ordering info.