Brake Master Cylinder Experts - Please Help!!
04-04-2012, 07:28 AM
#1
Brake Master Cylinder Experts - Please Help!! Guys,
Here is the back story. I have had weak brakes for the past year or so (car is rarely driven and weekend toy). I recently upgraded to a (new) older style Baer kit for the front with 13" rotors and the baer calipers. These are the older style/design patterned after the C4 vette but still much better than my stock lt1 calipers. The braking power is not really any better, so I moved to check my booster and vacuum to the booster as I have a choppy cam at 230/236 with an 108lsa. The vacuum showed 12" at idle at the booster so for good measure I installed a reserve canister and still not any better. The pedal is not hard and doesn't feel mushy but I'm starting to wonder if the internal seals in my MC could be leaking? Here's what I've done:
New pads/calipers/rotors up front
Stainless lines (all 4 corners)
Flushed the system fully and zero air/bubbles
Installed reserve vacuum canister
Check valve at booster is good
Booster is holding vacuum
When I stomp on the brakes it doesn't grip like it should and I can't even get the ABS to kick in. What else should I be checking and how could I test my MC to see if this is the culprit? Also, I did note that the fluid level in the MC reserviour raises about 1/4 - 1/8 inch when the brakes are applied, could this be a symptom the fluid is leaking past the piston (bad seals) or is this normal? Any help is much appreciated as these baer brakes should be pulling my eyeballs out when stomping on the brakes.
Here is the back story. I have had weak brakes for the past year or so (car is rarely driven and weekend toy). I recently upgraded to a (new) older style Baer kit for the front with 13" rotors and the baer calipers. These are the older style/design patterned after the C4 vette but still much better than my stock lt1 calipers. The braking power is not really any better, so I moved to check my booster and vacuum to the booster as I have a choppy cam at 230/236 with an 108lsa. The vacuum showed 12" at idle at the booster so for good measure I installed a reserve canister and still not any better. The pedal is not hard and doesn't feel mushy but I'm starting to wonder if the internal seals in my MC could be leaking? Here's what I've done:
New pads/calipers/rotors up front
Stainless lines (all 4 corners)
Flushed the system fully and zero air/bubbles
Installed reserve vacuum canister
Check valve at booster is good
Booster is holding vacuum
When I stomp on the brakes it doesn't grip like it should and I can't even get the ABS to kick in. What else should I be checking and how could I test my MC to see if this is the culprit? Also, I did note that the fluid level in the MC reserviour raises about 1/4 - 1/8 inch when the brakes are applied, could this be a symptom the fluid is leaking past the piston (bad seals) or is this normal? Any help is much appreciated as these baer brakes should be pulling my eyeballs out when stomping on the brakes.
04-04-2012, 10:11 PM
#2
what you might try with the engine off is pump the brake pedal easy until the pedal firms up as much and as high as possible. Then gently put force on the brake pedal, it should not travel far before it really firms up and doesn't move. Keep heavy steady pressure on there for a minute, if your foot slowly makes its way to the floor then there is a leak some where. if you've checked everything else then go for a master cylinder replacement.
If you have any reason to believe air entered into the system from the master cylinder reservoir, if the res. had gone dry, then i would get a power bleeder and find a way to put the ABS module into purge mode with a scanner, you might still have air in the system. best of luck.
If you have any reason to believe air entered into the system from the master cylinder reservoir, if the res. had gone dry, then i would get a power bleeder and find a way to put the ABS module into purge mode with a scanner, you might still have air in the system. best of luck.
