Hey guys I recently ran into a problem with my brakes. It happened suddenly while driving. The pedal went completely soft. No response. Had to handbrake it to stop. Bleeding the brakes made no diff. They were properly bled from pass rear to driver rear to pass front and driver front. Air is out.

whats weird is with the engine off, I get pedal stiffness. Its not fixed by any means but a great improvement over engine on. If I hold the pedal down and stop the engine the pedal neither sinks or rises after 2 mins. If I lift my foot the pedal returns and functions normally until I start the car again.

Check valve on the booster maybe? A leak?

 

The brake booster just helps assist the brakes with a vacuum. When a brake booster goes out the brake petal will be at normal height, but will be super stiff and will not brake well. It sounds to me that you have a bad master cylinder it has happened to me in my 92 da. I replaced the master cylinder and the problem was solved. I had similar symptoms.

 

Check for a leaking wheel cylinder.

Could be a pinhole but that's enough to lose pressure.

Does it get better if you softly pump then try to stop?

 

Sorry I work long shifts and just now got it fixed. Rear driver drum was leaking internally

 

i have a question i am havin a very similar problem with my del sol i just did a teggy rear disk swap and the brakes worked fine before the swap now the pedal goes almost all the way down, i pump it while the car is off and it feels normal once i turn it on it looses pressure, it has a 25/25 prop valve, any suggestions?

 

Check for leaks and bleed the system. See below.



This is NOT the correct sequence for your chassis. Your brakes are split diagonally not front and back.

Pass. rear
Dr. front
Dr. rear
Pass. front

 

ok, i checked for leaks and there isnt any, brakes have been bled 2 times, i replaced the right caliper yesterday it was stuck and changed the rear rotors and pads, havent bled the system yet im debating whether to use a solo man bleeder kit or do as my buddy did and run 4 small hoses from the bleed valves to the master cylinder open all 4 valves and pump the brake pedal till the air goes out. i also sourced a 30/30 prop valve my car has a 25/25 would the 30/30 prop valve help?