Vacuum Reservoir Check Valve

This valve is used on some vehicles equipped with catalytic converter.
1. Disconnect vacuum hose on reservoir which connects to electric solenoid valve vacuum nipple.
2. Connect a 0---30 inch Hg vacuum gauge to reservoir using a suitable length of hose.
3. Disconnect manifold vacuum hose from reservoir and connect an external vacuum source to the nipple. Apply 14 inches Hg vacuum to reservoir and trap. Vacuum reading on gauge should not drop more than 1 inch Hg in one minute. If it does, replace reservoir.