Problem with power brakes

He is refering to the rubber diaphrams inside the booster. If you have the small 7 inch booster then it has two diaphrams versus the larger booster that has one. I would think though that if you have a tear or hole in a diaphram then you would not be getting lockup (less vacumme). What is the pedal feel on your car. Have you disconnected the vacumme hose from the booster and pluged the manifold nipple and see what effect you have. It would be like going to manual brakes. Does it still lock up? That would eliminate the booster in the system. Are the pads installed correctly, are they the correct pads?

If all was working fine before you replaced any part then I would suspect the wrong part was installed or installed incorrectly. I know that I installed my brake shoes incorrectly and that caused some problems, like locking up, before I discovered my mistake.

Any more info would be helpful.

John B.