[Lance]

Thanks for the help. These problems have been there since I bought the coach 4 years ago. The air gauges, both the brake and supply gauges, go down at different rates. The brake gauge goes down faster than the supply gauge. I take it the brake gauge is the same air that keeps the bags full and that the front compressor works on. I had the brake system checked for air leaks and they said they didn't find any. I did have a stuck valve the other day. Is it worth it to replace all the valves after 13 years since the coach was built? It has been stored indoors most if it's life. It only has 75,000 miles on it and is in really good shape, except for all the problems. The supply lasts longer than the brake air when shut off, but it takes about 3 hours for both to be empty. Sounds like I have a few leaks around the coach. I don't hear anything and I sprayed down the brake valves and didn't see any bubbles. I guess they can work some times and not others.
Where's a good place to start to look for leaks and is there some routine to use to look for the leaks? I don't really know where to start.
also, until the other day, the gauges always read some pressure since the 12v compressor comes on to keep things working inside and the door. But now I have to turn on the key to see the 30 lbs of pressure where as 3 days ago it would always read the pressure without the key on. It's always something I guess.