p928

Currently I have a 1981 auto 928 with 46k miles. I have replaced all the pads, the 2 rear rotors (front rotors still good) and replaced a bad caliper. I purchased a powed bleeder and flushed the system twice. The pedal is still spongy, but the car stops.

Will the brake pressure regulator cause this? Can someone tell me how to check for failure? Any info would be most helpful.

Thanks

ErnestSw

You most likely still have air in your lines.

Mrmerlin

Hi if you flushed the system I would try bleeding the system with a helper to push the pedal and then open the bleeder then close and pump then open, do each bleeder one at a time, if the pedal is still spongy then the master cylinder is probably on the way out, dont use synthetic fluid as it may make the rubbers in the brake system soft, I recommend the ATE super blue racing fluid

p928

I just changed the master cyclinder. I also had a helper pump the brakes and bleed them. Recently I used a pressure bleeder to bleed the brakes again. I did make the mistake of not priming the master. The master I bought does not have a bleeder screw. Any ideas?