Mitsubishi Pick-ups and Montero 1983-1995 Repair Guide

Vacuum Check Valve



The vacuum check valve found in the brake booster line is a simple one-way valve. It is designed and placed to hold vacuum within the booster for use during periods of low engine vacuum.

To test the valve, blow into each end. Air should NOT pass when you blow from the engine side but should pass when you blow from the booster side. Make sure the valve is installed correctly in the vacuum hose when reinstalling.