I've had a chain of problems with my brakes since replacing the master. I blew a line in front, both wheel cylinders one at a time, o-ring at base of resevoir was bad, and when doing my pads the other day had a frozen piston in one of the calipers. Every time I've found one of these problems and fixed it I've bled out the air and still had no brakes. I have to pump 2 or 3 times to get feeling. I have tried the booster test but am not sure I'm doing it right due to poor pedal. Booster appears to work ok though. Is it possible the master from autozone is bad?