Ok well my 89 gtu has been sitting for a while. Both back brake calipers were locked up so i freed them up and rebuilt them. But now me pedal almost goes to the floor. They were properly bled, and there are no leaks. If the car is sitting for like 30 seconds and i push the brake the pedal almost goes to the floor, i have to pump it to get pressure, but once i have pressure and i keep my foot on the pedal it stays in place, it doesnt slowly go to the floor. What the hell is wrong, new master?

 

[quote name='rx7man629' date='Mar 25 2005, 07:59 PM']Ok well my 89 gtu has been sitting for a while. Both back brake calipers were locked up so i freed them up and rebuilt them. But now me pedal almost goes to the floor. They were properly bled, and there are no leaks. If the car is sitting for like 30 seconds and i push the brake the pedal almost goes to the floor, i have to pump it to get pressure, but once i have pressure and i keep my foot on the pedal it stays in place, it doesnt slowly go to the floor. What the hell is wrong, new master?


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If the brake pedal does not slowly go to the floor when depressed then you need to completely bleed the system again, all four sides. If the brake fluid had not been changed after sitting for so long, change it. Check the brake master cylinder for leaks and make sure there is no moisture around the area. Re-check all the calipers and lines for leaks. if no leaks are found check the pads to see if they need replacing. Report back here if you found the problem or not.

 

Ive seen a lot of master cylinders go bad, and the symptoms match yours.

 

[quote name='mazdaspeed7' date='Mar 25 2005, 04:34 PM']Ive seen a lot of master cylinders go bad, and the symptoms match yours.


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You have trapped air in the master cylinder and your best bet is to pull it and bench bleed it. Many times, if the master cylinder is not bled while it is perfectly level, you'll have trapped air inside of it. On some cars, the master cylinder is installed at an angle or sits on an angle when installed and can't be bled properly.



I learned this the hard way when I returned 3 master cylinders to a parts store and the 3rd time I had a parts guy who actually knew **** about cars pull me to the side and tell me the deal about bench bleeding a master cylinder level.

 

How do you bench bleed the master?