Power Brake Booster
- Inspect all vacuum hoses and connections. All unused vacuum connectors and hoses should be capped. Hoses and their connections should be properly secured and in good condition with no holes or no collapsed areas. Inspect check valve on the power booster for damage. See Fig 1 .
- Check hydraulic system for leaks or insufficient fluid. With the transmission in Park or Neutral, stop engine and apply parking brake. Depress brake pedal several times to exhaust all vacuum in the system.
- With engine turned off and all vacuum in the system exhausted, depress the brake pedal and hold it in the applied position. Start engine. If vacuum system is operating properly, the brake pedal will tend to move downward under constant pressure. If no motion is felt, the power brake booster is not functioning properly.
- Remove power brake booster vacuum hose at check valve. Manifold vacuum should be available at the check valve end of vacuum hose with engine at idle and the transmission in Neutral. Ensure that all unused vacuum outlets are properly capped, secured and in good condition. Repair or replace power brake booster as necessary.