RAM 2500 Truck 2WD L6-6.7L DSL Turbo (2010)
Vacuum Brake Booster: Testing and Inspection
MASTER CYLINDER/POWER BOOSTER
1. Start the engine and check the booster vacuum hose connections. A hissing noise indicates a vacuum leak. Correct any vacuum leaks before
proceeding.
2. Stop the engine and pump the brake pedal until all vacuum reserve in the booster is depleted.
3. Press and hold the brake pedal under light foot pressure. The pedal should hold firm. If the pedal falls away, there may be an external leak or the
master cylinder is faulty (internal leakage).
4. Start the engine and note pedal action. It should fall away slightly under light foot pressure, then hold firm. If no pedal action is discernible, the
power booster, vacuum supply or vacuum check valve is faulty, proceed to the POWER BOOSTER VACUUM TEST.
5. If the POWER BOOSTER VACUUM TEST passes, rebuild the booster vacuum reserve as follows: Release the brake pedal. Increase engine
speed to 1500 RPM, close the throttle and immediately turn off the ignition to stop the engine.
6. Wait a minimum of 90 seconds and try brake action again. The booster should provide two or more vacuum assisted pedal applications. If the
vacuum assist is not provided, the booster is faulty.
POWER BOOSTER VACUUM TEST
1. Connect a vacuum gauge to the booster check valve with a short length of hose and T-fitting.
2. Start and run the engine at curb idle for one minute.
3. Observe the vacuum supply. If the vacuum supply is less that 12 inches HG (406 millibars), repair the vacuum supply.
4. Clamp the hose shut between the intake vacuum source and the check valve.
5. Stop the engine and observe the vacuum gauge.
6. If the vacuum drops more than one inch HG (33 millibars) within 15 seconds, the booster diaphragm or check valve is faulty.
POWER BOOSTER CHECK VALVE TEST
1. Remove the power booster check valve from the power booster.
2. Using a hand operated vacuum pump, apply 15-20 inches HG (508-677 millibars) vacuum at the booster side of the check valve.
3. The vacuum should hold steady. If the gauge on the pump indicates vacuum loss, the check valve is faulty and should be replaced.