Power Brake Booster
- With engine off, depress brake pedal several times. Press and hold brake pedal. Start engine. If brake pedal moves down slightly immediately after engine starts, power brake booster is operating as designed. If brake pedal does not move as specified, go to next step.
- Run engine for 1-2 minutes. Stop engine. Press brake pedal several times and note if first pedal stroke is longer than subsequent strokes. If first pedal stroke is longer than subsequent strokes, power brake booster is operating as designed. If length of strokes is equal, test check valve and vacuum hose between vacuum source and power brake booster and examine installation. Repair as necessary, and go to next step.
- Start engine. Press and hold brake pedal. Stop engine. Hold pedal down for about 30 seconds. If pedal height remains at same height, power brake booster is operating as designed. If pedal height recedes, test check valve and vacuum hose between vacuum source and power brake booster. Repair as necessary.