Power Brake Unit
CAUTION:
Do not remove check valve from booster. Do not disassemble power brake unit. Booster is serviced as complete unit only.
NOTE:
Ensure proper ABS or non-ABS booster is used.
- With engine off, depress and release brake pedal several times to purge all vacuum from power brake booster. Depress and hold pedal with light pressure of about 15-25 lbs. (6.8-11.3 kg), then start engine. Pedal should fall slightly, then hold. If pedal did not fall continue with testing.
- Disconnect vacuum hose on side of vacuum check valve that leads to speed control, then connect a vacuum gauge to open vacuum port on valve. Start engine. When engine is at warm operating temperature, allow it to idle and check vacuum at gauge. If vacuum supply is 12 in. Hg or more, power brake booster is defective. If vacuum supply is less than 12 in. Hg, continue with testing.
- Shut off engine. Connect vacuum gauge to vacuum reference port on engine intake manifold. Start engine and observe vacuum gauge. If vacuum is still low, check engine (tune and repair as necessary). If vacuum is greater than 12 in. Hg, hose or check valve to booster has a restriction or leak. Once an adequate vacuum supply is obtained, repeat testing.