[77newell]

Ron: How you are hanging in there is amazing, I'd be so ticked the coach would have been for sale days ago. I can't imagine how all your compressors would fail at the same time, so for the moment I'm guessing your air supply is fine but there is a large leak somewhere in the non-brake air systems. The Pressure Protection Valve on the bulkhead ahead of your rear axle keeps that leak from draining the brake air systems below 75psi. As long as your engine was cranked up it would supply enough air to keep up with the leak, but not when you are stopped or at idle. I would start my 120v pump and listen for leaks - starting at the rear of the coach because that is where the shops were messing around.

I sure hope this is useful information given the distress you are experiencing.