sorry for the profanity. ive installed 3 master cylinders on my 67 power disk car. this is the large oval looking piece with a divider and the 2 bails for the cover. im assuming this is the proper master cylinder for the car. shortly after putting them on fluid is running down the front of the break booster. the leak apperas to be coming from the back side of the M.C. am i doing somthing wrong? i bench bleed them and install. these are rebuilt units. i had the auto parts store order a NEW one today Ideas? thanks Dave

sometimes if you go the "cheap" route, it takes a few tries to get a good part. had the same problem last spring on my Nova- 2 reman masters leaked out the back of the piston like yours, and the third one i got has been fine ever since. i wonder if it's a coincidence that the "good" one came in a reman box, but actually looks like a new one. the first 2 were kind of raggedy looking, but the third one was all shiny and new looking...

Just changing mine on the 69,made sure it was new and not reman.Don't want to do it twice!!!
Mike

Must agree, have tried remanufactured ones and have taken them back. Don't know why but they seem to have a problem getting it right the second time around. Never bother with them anymore, strictly new master cylinders now

I had a similar leak. Turns out the aftermarket chromed lid was hitting on the master cylinder and wasn't seating on the seal. Brake fluid would splash out and down the booster. Chromed lid in the garbage and new lid under the hood. No more problem. Took three trys to get a good master cylinder for our el Camino.