Bore End Seal Leak Test

1. Press the brake pedal several times to exhaust all vacuum in the system.
2. Disconnect the brake warning indicator switch connector, if necessary.
3. Remove two nuts retaining brake master cylinder to power brake booster assembly.
4. Slide brake master cylinder forward away from booster.
5. Inspect end of master cylinder bore for signs of excessive leaking. Some fluid is normal due to the wiping action of the seal.
6. Inspect inside booster for presence of brake fluid. A plastic tie strap can be inserted through push-rod opening or through booster check valve opening and into bottom of booster and checked for fluid.
7. If excessive fluid is found, master cylinder will need to be removed and overhauled.
8. Booster should be replaced if brake booster is contaminated with brake fluid.
9. Position brake master cylinder on studs on booster assembly.
10. Install retaining nuts. Tighten retaining nuts to 21-29 Nm (16-21 ft. lbs.).
11. Connect brake warning indicator switch connector.