[sweetbmxrider]

I was thinking the same thing, Bill. I would look at maybe the master being the issue. Could be the pushrod hanging up and maybe even causing a bad vacuum seal? I'd pop it out, look it over, and try reinstalling and retesting.

edit: Actually, get the brakes locked up on the lift, then disconnect the master and see if they remain locked up. You could also pump the pedal till its rock hard with the motor off, then start it with your foot on the pedal and see if it drops. That would rule out a bad booster.