Thanks, I'll try it with the engine running. The problem is it won't build up a pedal no
matter how much you pump the brakes with the engine running. It just keeps making
wooshing air sound and goes down to about 2" off the floor. I know that sounds like a
master cylinder but it is new and bench bled and it has a good pedal when the engine
isn't running or the booster isn't working. Is it possible the atmospheric check valve is
bad in the booster causing an over boost that is pushing fluid past the master cylinder
seals? Just another wild guess. This one has me stumped.