Vacuum Leak Test
WARNING: This page is about a different car, the 2002 Dodge Intrepid, 2002 Chrysler Intrepid, 2002 Chrysler Concorde, and 2002 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect the vacuum hose on the side of the power brake booster vacuum check valve that leads to the speed control, then connect a vacuum gauge to the open vacuum port on the valve.
- Remove the remaining hose on the vacuum check valve that is not the vacuum supply hose coming from the intake manifold. Cap off the open port on the check valve.
- Allow the engine to warm up to normal operating temperature and idle engine.
- Using vacuum line pliers, close off the vacuum supply hose coming from the intake manifold near the booster and observe the vacuum gauge.
- If the vacuum drop exceeds 1 in. Hg in one minute, repeat the above steps to confirm the reading. The vacuum loss should be less than 1 in. Hg (3.4 kPa) in one minute time span. If the loss is more than 1 in. Hg, replace the power brake booster. See POWER BRAKE BOOSTER under REMOVAL & INSTALLATION. If the loss is less than 1 in. Hg, go to next step.
- Remove the pliers from the hose temporarily.
- Apply light effort (approximately 15 lbs. of force) to the brake pedal and hold the brake pedal steady. DO NOT move the pedal once the pressure is applied or the test results may vary.
- Have an assistant reattach the pliers to the vacuum hose.
- Allow 5 seconds for stabilization, then observe the vacuum gauge. If the vacuum drop exceeds 3 in. Hg, replace the power brake booster. See POWER BRAKE BOOSTER under REMOVAL & INSTALLATION. If the vacuum loss is not more than 3 in. Hg, the power brake booster is not defective.