A: This Dorman - Help Vacuum Check Valve - Universal - part# 47149 is meant as a washer fluid anti drain back valve. It wouldn't be rated for more than 5 psi. As far as vacuum, around 15-18 inches. For any further assistance, please visit your nearest Advance Auto store or call us directly at 1-877-ADVANCE (238-2623) and one of our representatives there would be more than happy to assist you.
A full line of leak-proof, one-way vacuum check valves that are designed to optimize vacuum pump performance in a wide range of material handling systems is available from ANVER Corporation of Hudson, Massachusetts.
To test the vacuum check valve, disconnect the vacuum supply hose from the intake manifold or vacuum pump and blow into the hose. If air passes through the valve into the booster, the check to see if the valve is defective and should be replaced.
Release and rest mode are the same. When the pressure generated by the pedal is released, the vacuum valve opens, the pressure from the boost chamber(s) is evacuated, and the power piston is returned to its rest position by the spring in the main vacuum chamber. The vacuum check valve is a key component to the operation of the booster.