Vacuum Dump Valve Test
- Vacuum dump valve should be checked whenever brake application does not release speed control. Ensure no more than 1/8 of plunger tip is extended when brake pedal is fully released. Disconnect vacuum hose from dump valve to servo, at servo unit. Connect hand vacuum pump to hose and pump up a vacuum.
- If vacuum cannot be obtained, hose or dump valve leaks and should be replaced. Depress brake pedal. Vacuum should be released. If not, adjust or replace dump valve.