Vacuum Brake Booster Check Valve: Testing and Inspection

Removing Vacuum Hose For Check Valve Operation Check:

When checking the check valve, keep the check valve fit in the vacuum hose.
1. Remove the vacuum hose.

NOTE: The check valve is press-fitted inside the vacuum hose.

2. Check the operation of the check valve by using a vacuum pump.

Using Vacuum Pump To Check Operation Of Check Valve:

Vacuum pump connection at point A; Brake booster side, should create and hold negative pressure (vacuum).
Vacuum pump connection at point B; intake manifold side, should not create negative pressure (vacuum).

CAUTION: If the check valve is defective, replace it as an assembly unit together with the vacuum hose.