Dakota 4WD V6-239 3.9L VIN X FI (1989)
Vacuum Brake Booster Check Valve: Testing and Inspection
Fig. 1 Typical Vacuum Check Valve And Seal
Fig. 2 Typical Hand Held Vacuum Pump
1. Disconnect vacuum hose from check valve.
2. Remove check valve and valve seal from booster.
3. Hand operated vacuum pump can be used for test.
4. Apply 50.5-67.3 kPa (15-20 inches vacuum) at large end of check valve.
5. Vacuum should hold steady. If gauge on pump indicates any vacuum loss, valve is faulty and must be replaced.