[77newell]

Lance: If it were me I would be first checking the drains on the bottom of my brake tanks - they are the two front ones on my coach. If your brake tanks are dropping ahead of the supply tank then there is a leak in the brake supply system, but not the brakes themselves since they are under pressure only when braking - except for the emergency brake canister when running down the road, so if pressure is dropping when parked the leak is somewhere between the outlet of the pressure protection valve on the supply tank and the inlet to the brake control valves.

Then I would go after the leveling system. If the coach drops with the HWH in the manual mode, then it is not the height control valve (HCV) since the bags are isolated from that valve in that situation. The bags can only leak down by air from the bags escaping to the atmosphere which is lower in pressure. With the HWH in the manual mode and pressure being maintained in the supply tank, do the bags deflate? If yes then your raise valves in the six-pack are OK. If no, then those valves are leaking. If with the HWH in the manual mode there is air leaking (bubbles or leak detector - I prefer bubbles for this one) then at least one of the down valves is leaking. If you use the HWH to manually raise the coach and the HCV's start exhausting then the six-pack valves isolating the HCV's are leaking. There are also orings that can leak local to the solenoid valves on the six-packs.

On the front of the coach in the space behind the front fascia below the driver seat my 93 coach has a manifold with 6 taps on it, these are for other uses of air from the supply tank to be checked by blanking them off and seeing what your pressure does. On my coach this manifold is where the supply pressure gauge gets its pressure.