How do I determine if a hard pedal complaint is power booster-related or a foundation brake problem?
The easiest method is to deplete air from the vacuum booster by pumping the pedal until it’s hard. Next, with the engine off, hold foot firmly on the brake pedal and start the engine. The pedal should drop slightly with engine vacuum and become firm if power booster is operating correctly. If hard pedal condition still exists check for binding linkage or over adjusted drum/shoe assemblies.
