Dennis, You say that you don't believe the MC was the culprit but you offer no other explanation??? This is kind of strange but I had something exactly like this happen after a rear end swap. I kept reasoning that it could not be the master cylinder. I went through about 5 quarts of brake fluid trying this and that. I can remember my leg aching from all the pumping. It was really crazy because I would get the pedal just about right and then they would fade again. Long story short, I bought a new MC and bled the system once and the pedal was rock hard. This isn't rocket science. The only tricky part is the MC. The only other thing it could be is Human error.
This isn't rocket science. The only tricky part is the MC. The only other thing it could be is Human error.
