Vacuum Brake Booster Check Valve: Testing and Inspection

CHECK VALVE INSPECTION
1. Disconnect the vacuum hose.
2. Check to be sure that air passes to the engine and not from the engine when air is taken in from the power-brake unit side of the vacuum hose.

NOTE:
- The check valve is pressed into the vacuum hose, and there is an arrow on the hose surface to indicate the installation direction.