OEM Jeep Cherokee Brake Booster

Jeep Cherokee Brake Booster Parts and Q&A

• Brake Booster
  4856672AC
  Q: How to Troubleshoot and Repair a Brake Booster and What Should You Know for Your Jeep Cherokee?

  A:

  Before starting the service of the vacuum brake booster, disconnect the Brake Lines at the master cylinder and the wire at the combination valve differential pressure switch. Lift off the nut mounted on the bracket for the combination valve and bring out the valve. Then, unscrew the nuts securing the master cylinder to the booster studs and let the cylinder come free. Take the vacuum hose away from the booster check valve, then get rid of the knee blocker under the steering column. Unscrew and take out the nuts that hold the booster to the dash panel next to the passenger compartment, along with any attached clip at the brake pedal. In the engine compartment, take out the booster studs from the dash panel, stand the booster on its end and bring it out of the car. When removing the booster, pull off the dash key from the booster also. Set the dash seal on the booster seat at first, then adjust and set the booster seat on the dash panel. Tighten the nuts where the booster mounst in the passenger compartment, just as tight as necessary to hold it. Slide the booster push rod onto the brake pedal and fasten it with the retaining clip after applying Mopar multi-mileage grease to both the pedal pin and bushing. Apply 39 Nm torque (29 ft. lbs.) to each booster mounting nut and install the knee blocker again. Replace the seal at the rear of the master cylinder if you find that it is torn or damaged when using the original master cylinder. Rub the brake booster's surface where it connects to the engine cylinder with a damp shop towel and brake cleaner to avoid vacuum leaks. Position the master cylinder on the turbo studs, insert the mounting nuts and heat-tighten them to 17.5 Nm (155 inch lbs.). Attach one end of the vacuum hose to the booster check valve and the other end of the brake lines to the combination valve and master cylinder, holding each connection by hand at the start to avoid cross-threading. Put the combination valve onto the booster studs, tighten the nut bracket to 17.5 Nm (155 inch lbs.) and finally attach the wire to the combination valve switch. Be sure to bleed and fill the base brake system, check the brakes and then move the vehicle.