did you put in a stock master cylinder. i put a 60 and 44 in my jeep and i would go threw MC like once a month the guy i sold it to put a corvette MC on it and soved the braking issues. of course the MC were high quality advance auto reman's w/ lifetime warranty they were definetly sick of me getting new ones every month.
If you have a power brake booster, then be sure to get the MC from a vette with power brakes, which has a bigger bore, 1 1/8" IIRC. Manual brake vettes were 1".
Telling the parts counter guy the vette was from the 70's seemed to make it easier to find..
we got one, but the piston shot out and snapring was gone, so we returned it, and are waiting on another to come in. they dont stock em for some reasson...