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I have an 81 vette finished replacing everything on it about 6 months ago suspension/motor/trans. Bought a new master cylinder and brake booster. (separate) Master cylinder started leaking at back where connects to booster. Also put a chrome cap and seemed it was leaking from cap also. Got tired of messing with and so bought a new A/C Delco master cylinder that came with new regular cap. Put it on last weekend and now its leaking in same spot in the back. Seem the cap is fine now, the chrome top didn't fit that tight. I used the rod that came with the brake booster I bought when I replace the motor. Think the push rod is too long or can I adjust it in anyway? Since it probably broke the seal on the A/C Delco master cylinder I just bought I'm thinking of just buying a Master cylinder/booster set and be done with it but man that booster is a PAIN to unbolt and get to!!!
If the pushrod is adjustable you would see an adjustment nut. Can you measure how far out the pushrod extends from the mounting surface on the booster and how far in the piston cup is on the master?
Those chrome caps are prone to leaking. Original style caps work better.
If the leaking persist in the back where it connects to the booster than the gasket shown in the picture might be the cause.
Master Cyliner leak
