Vacuum Booster Check Valve
- Remove vacuum booster hose from power brake booster and check valve connection. Manifold vacuum should be available at check valve end of vacuum booster hose with engine idling and transmission in Neutral.
- Operate engine a minimum of 10 seconds at fast idle. Stop engine, and let vehicle stand for 10 minutes. Apply brake pedal with about 20 lbs. (9 kg) of force. Brake pedal feel should be same as that noted with engine operating. If brake pedal feels hard, replace check valve and retest.