Mopar 5142651AA Power Brake Booster

The brake power unit doesn't need extra care; you only need to check the condition of the vacuum hose and the case every now and then, and if something goes wrong, you have to replace the entire unit. Hit the brake pedal several times without running the engine to make sure brake response doesn't change. Then, press the pedal and start the engine; if the pedal sinks a bit, the brake works normally. To make sure your brake booster has no air leaks, switch on your engine for a couple of minutes and then shut it down. Depress and release the brake pedal several times. Good sealing when the pedal first dips a bit and stays there. When the engine runs, hold down the brake pedal, and stop the engine with the pedal still pressed down. If your pedal travel doesn't change after keeping the pedal engaged for 30 seconds without loss of pressure, your booster holds air tightly. To detach the booster, unwind its hose from the brake booster and then pry off its push-rod clip at the pedal's top before loosening the firewall bolts. Take care to lift the booster out of the engine space by the firewall, paying attention to how gaskets and spacer blocks should fit in place. Position the booster, lock down the retaining nuts tightly to specs, attach the booster push rod with the brake pedal, install the master cylinder, hook the vacuum hose to the assembly, drain the brakes completely before putting it back to normal road use.