Del70

I replaced the power booster and master cylinder and lines from the master cylinder to the proportioning vale. The car hasn’t been driven since installation. I have bleed the lines at the front, started the car etc. a few times, pumped the brakes, feels okay. But I have notice a few times, when I press the pedal for the first time after the car sits (it not being driven now) , the pedal sticks for a second then it is fine. Never had this before. I only replaced the booster because I have the fender off and it was easy to change (got new booser from I.L.T). The master cylinder is a rebuilt unit. I suspect it is the master cylinder (a junk rebuilt unit maybe)..I did not make any adjustmenst to the power booster setup rods. Measurements were in line with my factory booster… 70 Cutlass power with drum system
Any thoughts...thanks

ragtop71

Hello del 70 I had same problem, well when I hit the brakes every once in a while they would stick for a second then release well I automatically started thinking bigger parts, master cylinder, calipers ect. and it turns out after several dollars later that it was a one dollar brake line starting to collapse on the inside. the line(rubber) to front caliper was hard rubber on outside but apparently has another softer line on the inside sort of two ply line and that was in process of collapsing. It would allow fluid through while depressing petal but would hinder release of fluid pressure causing calliper not to fully release and of coarse I replace calliper first thinking big but when the new one reacted the same way we inspect line and oh well problem solved!!

Del70

Thanks. Mine sticks the first time you push on the pedal after the car sits. Like something is binding it for a second, it returns fine. I plan to call the Mfg of the booster today to see if they feel it is the booster or an adj. of it ..otherwise I will just may swap out the master cylinder , easy to change, it is a re-man and I have not had a lot of good luck with re-manufactured items lately. It is the second master cylinder I have put on it . This one didn't seem to bleed well when I did the bench bleeding, didn't pump well.. Something just did not feel correct, but it pumped fluid... so maybe this is the culprit..Then I will look at the rubber lines to the front drums (which are two years old)..thanks