I recently had a spare power brake booster for my 1980 242 polished to improve its appearance. When I installed it its performance was not correct. With the engine off, the brake pedal is vry stiff and hold position when being pressed. Master cylinder is good. Upon startingthe engine there appears to be plenty of boost, as the pedal goes down very easily, infact too easily, and seems to touch the floor. The brakes do catch, but seemingly only near the bottom of the pedal travel and then very quickly and suddenly. When I replaced the newly polished booster with the oriingal one, the brakes functioned normally, so the "problem" is in the polished booster. I always thought that a malfunctioning boostrer would give no boost, not a lot of pedal travel and seemingly too much boost. By the way, check valve is OK, and no hissing sounds of any kind indicating vacuum leaks. Ideas on possible adjustmetns that can be made, or is the booster bad ?

Mike