[Richard]

I was lucky in that the rear air bag failed in a campground. The failure was caused by fluid leaking from the rear slide hoses onto the front of the two rear air bags in the driver side rear wheel well. The rubber in the bag was softened by the ATF and the bag simply delaminated. 

The coach sits flat on the wheels when this happens. Duh. 

Newell overnighted a bag at a respectable price. 

Here are a few tricks I learned and used in the removal and replacement. I had to use both of my 20 ton bottle jacks under the radius arm mount in order to lift the coach. Of course, I chocked the coach with wooden cribbing. As Steve posted in the other thread about rear bags, there are two studs on top, and one on bottom. A 3/4 wrench removed those easily. And the connection to the air fitting was handled with a big adjustable wrench. The removal process went south at this point. There is a 45 degree angle fitting on top of the bag that would not turn, and the bag will not come out of hole without removing the fitting. I could only get a 1 1/2 wrench on the fitting at two angles, neither of which would give me any leverage way up in the frame rail where the fitting is located. It is really tight up in there working around the differential and hydraulic fan cooler. 

I eventually cut it off with a side grinder and cutting wheel. Ugly, but effective. 

Then while at the local hydraulic place getting a replacement fitting, which by the way is  45 degree 1"NPT by 1" JIC (16), I had a eureka moment. The place had a big selection of crow's feet wrenches. This is the point of the post. The crows feet allow many different angles of approach when used with a flex head breaker bar. It was a piece of cake tightening the new fitting into the air bag, and tightening the air line connection using the crows feet. One of those wrenches in the right size would have saved me four or more hours of vocabulary creativity enhancement. 

So check the wheel well if you have a two slide HWH coach to make sure lines aren't leaking on the air bag. The failure would have been nasty on the road. And, if you take replacement of the air bags on yourself, think about getting a few crow's feet to fit the air line fittings.

Now, I have to figure out how to access the hose where it attaches to the cylinder. I know, under the bed, but it's under the part of the bed that doesn't lift.