Help me diagnose my brake problem.
Thread Starter
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Help me diagnose my brake problem.
Scenario starts out about a month ago, going down the road, realize pedal is TERRIBLE.
Bleed all lines. Pedal stops with about 2" of distance between foot and floorboard. Much better, not great.
Drive car once a week for 2 weeks. On second trip, pedal turns to mush again. Discover RF rim wet on inside. Replace both front calipers, RF had blown seal. Pedal back to 2".
No air in lines. Fluid in master is clear. Fluid leaving brake bleeders is clear with no debris or air.
Hard pedal action does not cause a pull in either direction, car stops straight.
I'm thinking the M/C is gone. Replaced it with a parts store rebuild somewhere between 2 and 3 years ago, but ... it's a parts store rebuild.
I swear the pedal was better than this at some point... I could probably stick both my feet under the pedal with it at the bottom of its travel with the engine off.
If it is the M/C, any recommendations on what route to take? The original, sadly, is gone. I'm thinking NEW Delco. This is a 78 Pace Car (power brakes).
Bleed all lines. Pedal stops with about 2" of distance between foot and floorboard. Much better, not great.
Drive car once a week for 2 weeks. On second trip, pedal turns to mush again. Discover RF rim wet on inside. Replace both front calipers, RF had blown seal. Pedal back to 2".
No air in lines. Fluid in master is clear. Fluid leaving brake bleeders is clear with no debris or air.
Hard pedal action does not cause a pull in either direction, car stops straight.
I'm thinking the M/C is gone. Replaced it with a parts store rebuild somewhere between 2 and 3 years ago, but ... it's a parts store rebuild.
I swear the pedal was better than this at some point... I could probably stick both my feet under the pedal with it at the bottom of its travel with the engine off.
If it is the M/C, any recommendations on what route to take? The original, sadly, is gone. I'm thinking NEW Delco. This is a 78 Pace Car (power brakes).
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I used to buy reman masters and replace them religeously once a year. That was when new was really expensive. New is always better.
If loosing fluid also check firewall side of MC.
If your not losing fluid then MC probably leaking internally.
Here is a shadetree test.
Pump the pedal hard a bunch of times to try and raise it and then just stand on it hard for a while to see if it lowers slowly. If it goes down eventually you either have an external or internal leak. If it stays upand a little spongy then you probably still have air in the lines. I would only trust pressure bleeding on these systems.
If loosing fluid also check firewall side of MC.
If your not losing fluid then MC probably leaking internally.
Here is a shadetree test.
Pump the pedal hard a bunch of times to try and raise it and then just stand on it hard for a while to see if it lowers slowly. If it goes down eventually you either have an external or internal leak. If it stays upand a little spongy then you probably still have air in the lines. I would only trust pressure bleeding on these systems.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Good man!
That should have been enough. Sometimes it's good to to the pump up trick and bleed agian just for fun.
Make sure you bleed long enough. It's hard to tell if the old and new fluid is clean.
That should have been enough. Sometimes it's good to to the pump up trick and bleed agian just for fun.
Make sure you bleed long enough. It's hard to tell if the old and new fluid is clean.
Thread Starter
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Originally Posted by noonie
Good man!
That should have been enough. Sometimes it's good to to the pump up trick and bleed agian just for fun.
Make sure you bleed long enough. It's hard to tell if the old and new fluid is clean.
That should have been enough. Sometimes it's good to to the pump up trick and bleed agian just for fun.
Make sure you bleed long enough. It's hard to tell if the old and new fluid is clean.
Could be I still have air in the front lines I suppose. I'm just amazed it doesn't pull.
