Hi Folks,
Well, I'm getting towards the end of my tether. I've done a fairly complete brake rebuild on my car (new calipers and pads all around), and can't get good pedal pressure. There is no leakage. I've bled the system the old-fashioned way, and now also with a Motive pressure bleeder.

Here is the funny symptom: I get done bleeding, have great pedal pressure, put the car down off the jacks, start the car and suddenly the pedal sinks! There is a slight whooshing sound, and it goes mostly to the floor. But just after I've bled the system (and before starting the engine), I have great firm high pedal.

I suspect that the booster is the likely culprit. The only other thing I can think of is that I still have air in the master cylinder. Is there a test to see what exactly the problem is? Can I rebuild the booster? Could I have damaged the booster by pressing too deep on one of my (numerous) bleeding attempts? (I know this can ruin a master cylinder).

Any advice would help.

thanks,
Tom