Check Valve Operation Check

WARNING: This page is about a different car, the 2017 Mitsubishi Mirage. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: The check valve should not be removed from the vacuum hose.

Remove the vacuum hose (Refer to MASTER CYLINDER ASSEMBLY AND BRAKE BOOSTER ASSEMBLY ).
CAUTION: If the check valve is defective, replace it as an assembly unit together with the vacuum hose.

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

Vacuum pump connection	Accept/reject criteria
Connection at the brake booster side (A)	A negative pressure (vacuum) is created and held.
Connection at the intake manifold side (B)	A negative pressure (vacuum) is not created.

Fig 1: Checking Operation Of Check Valve

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.