Power Brake Unit
- Start engine, run it 1-2 minutes, and then turn it off. Depress brake pedal several times using normal pedal force. Each time pedal is depressed, pedal height should increase. While brake pedal is depressed, start engine. Pedal should move slightly toward floor. Continue to hold brake pedal down and turn off engine.
- Continue to hold brake pedal down longer than 30 seconds. Brake pedal height should not change. If pedal goes slowly upward, a vacuum leak exists in power brake system. Inspect brake vacuum check valve for proper operation. If check valve is okay, replace power brake unit.