Brake pedal too firm after new Master Cylinder installation
A couple of weeks ago I was taking the orange 72 for a ride and in the last mile or so the pedal started to go to the floor as I sat at stop signs. Given that the only part not replaced a few years ago was the aftermarket master cylinder I knew where the problem was (car had sat 15 years previously). After talking to the car's owner we decided to purchase and install the new "correct" reproduction. The car has power brakes, and the original booster is still in place.
I order the repro and installed in on Wednesday after bench bleeding it. The entire system was then bled. No issues, and because it was raining I did not test drive the car. Yesterday the owner came over and was ready to pick it up, but we found that on driving it the pedal was really, really firm, had little play before stopping, and the car stopped slower than expected. We test drove it around town, no improvements noted, so over a few hours last night we bled it 3 times with no change in pedal feel or road function. I checked the depth of the pushrod hole and it matched the previous MC, we checked the pushord and we checked how it all seated together. No issues were found. All 4 calipers are working and the wheels turn freely when brakes are not applied.
As it sits, every time you press on the brakes you have to push quite hard, and it really is like pushing on a brick. This is vastly different than the cars has ever been before. It is like all of the "feel" is gone from the brakes, and it is more like pushing on a non-power brake pedal than a power brake pedal. The other two PB Corvettes here feel nothing like this as well. If you stomp on the pedal as hard as you can it will not lock the tires or even get close. You will stop, but not quickly.
Given that the only part that was changed is the master cylinder my assumption (!) is that the new master cylinder has a problem. Would you agree? I plan on calling the vendor on Monday to see about getting a different one if consensus is that the MC is at fault.
Patrick
I order the repro and installed in on Wednesday after bench bleeding it. The entire system was then bled. No issues, and because it was raining I did not test drive the car. Yesterday the owner came over and was ready to pick it up, but we found that on driving it the pedal was really, really firm, had little play before stopping, and the car stopped slower than expected. We test drove it around town, no improvements noted, so over a few hours last night we bled it 3 times with no change in pedal feel or road function. I checked the depth of the pushrod hole and it matched the previous MC, we checked the pushord and we checked how it all seated together. No issues were found. All 4 calipers are working and the wheels turn freely when brakes are not applied.
As it sits, every time you press on the brakes you have to push quite hard, and it really is like pushing on a brick. This is vastly different than the cars has ever been before. It is like all of the "feel" is gone from the brakes, and it is more like pushing on a non-power brake pedal than a power brake pedal. The other two PB Corvettes here feel nothing like this as well. If you stomp on the pedal as hard as you can it will not lock the tires or even get close. You will stop, but not quickly.
Given that the only part that was changed is the master cylinder my assumption (!) is that the new master cylinder has a problem. Would you agree? I plan on calling the vendor on Monday to see about getting a different one if consensus is that the MC is at fault.
Patrick
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