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Been searching for an air leak when parked. Finally found air bubbling out of the exhaust port on the foot valve. According to this trouble shooting chart, foot valve should be replaced. So I did just that. And the air is still bubbling out of the exhaust port when parked with brakes set.
What in blazes is going on?
http://www.meritorwabco.com/MeritorWABCO...tp9973.pdf

Possibly you got a bad valve? It's rare but does happen.

If the valve has quick-connect fittings, it could be the end of the hose is stiff and brittle.

To start with-the charts were wrong. I had to open up the floor again to get to the foot valve. Then start taking the delivery lines off until I found the one that had air pressure in it. That led to the tractor abs/traction control valve. If I put my thumb over the leaking line, it would build pressure and start applying the brakes.
Replaced that valve. Bingo! After an hour I still have full air pressure!!