2012 Unlimited Sport S
Tools & Supplies
Dead blow hammer
Pair of jackstands
1/2" or 3/8" drive breaker bar
1/2" or 3/8" drive ratchet
1/2" or 3/8" drive extensions
1/2" or 3/8" drive 18mm socket
1/2" drive 13mm 12 point socket
6mm allen wrench
Small flat blade screwdriver
18mm combination wrench
Bungee cord or zip ties
A. The JK Wranglers feature a parking brake setup consisting of an apply/release lever next to the driver's seat, a pair of cables, actuator links and cams, and parking brake shoe assemblies.
B. Owners seem to think the parking brake system works great or it's "craptastic, garbage, or junk". LOL The system design is fairly simple, but does require periodic inspection/maintenance, especially if your Jeep is subject to frequent drives thru mud and/or deep water.
C. Contrary to popular belief, the parking brakes are not self-adjusting. However, once you understand how it works, adjustment is relatively simple and will ensure a properly functioning parking brake.
D. A properly adjusted parking brake system (4 - 8 clicks of the lever) should easily hold a Jeep on an incline.
E. The rear axles do not need to be removed to adjust/clean the parking brakes. Axle removal is only necessary when replacing the parking brake shoes or cam.
F. The parking brake system also serves as an emergency brake in the event of a failure in the hydraulic brake system. Push in and hold the release button on the top of the lever and then pull the lever up slowly to help stop.
Components & Operation
A. A pair of brake cables are attached to the parking brake lever mechanism alongside the driver's seat. They exit through the tub and are routed to the rear of the Jeep where they split. One cable to each wheel.
B. The cables are anchored to brackets on the axle tubes and end with a spring loaded hook. The hook is attached to the actuator link which passes through a dust boot and connects to the actuator cam inside.
C. Each of the rear brake rotors includes a "hat" that surrounds the parking brake shoes.
D. When the parking brake lever is applied (pulled upward), the cables in turn pull on the actuator links. The links force the cams to push the shoes against the inside of the hat and prevent the rotor/wheel from turning.
The shoes are mounted horizontally to the backing plate.
E. On the opposite end is the locating spring and parking brake adjuster, commonly referred to as the "star wheel". The spring keeps the shoes together and also prevents the star wheel from turning due to vibrations.
The back plate features a rubber knockout plug that allows access for adjustments.
F. In the center of the parking brake shoes is the ABS wheel speed sensor and tone ring.
NOTE: Adjustment is done with the rotor installed. For purposes of this write-up, I took the rotor off so you can better see what needs to be adjusted.
1) Examine the brake cables for visible damage from where they come through the tub back to where they attach to the actuating links. Make sure they are anchored to the axle tube and the spring on the end of each cable is ok.
2) Loosen the wheel nuts, raise the rear of the Jeep, and place a jackstand under the axle tube on each side.
3) Remove the two 18mm bolts holding the brake caliper and move it aside. Hang it from the frame using a bungee cord or zip ties.
CAUTION: Do not let the caliper hang by the hose.
Note: you may wish to remove the sway bar end link to allow more room for removing the caliper bolts.
4) Remove the rotor/hat. If it is rusted in place, spray PB Blaster or a similar penetrating oil on the rotor where the wheel studs pass through.
Using a dead blow hammer, rap the hat sharply until he rotor becomes free.
5) Once the rotor is off, inspect the parking brake shoe assembly for wear, extreme rust, or mud build-up. Replace the shoes if they are worn to less than 1/32". Clean out any mud or rust with a wirebrush/screwdriver and compressed air or water from a garden hose. Once the assembly is clean, allow it to dry.
6) Check the inside of the rotor hat for cracks or scoring. Light scoring may be removed on a brake lathe. Deep scoring or cracks will require the rotor to be replaced. The minimum dimensions are cast into the inside of the rotor.
7) Install the rotor back on the end of the axle.
8) Remove the rubber plug from the access hole on the inside of the backing plate (next to the ABS wheel speed sensor harness).
9) Using a flashlight, insert a small flat blade screwdriver in between the spring and the side of the adjuster.
10) Passenger side:
with a brake spoon or flat blade screwdriver, turn the star wheel COUNTER CLOCKWISE
until the shoes are against the rotor hat.
NOTE: The star wheel should turn easily and then suddenly become difficult to move. Stop!
11) Turn the star wheel CLOCKWISE
while counting the "points" or "notches". Once you have turned the star wheel 4 - 5 points or notches, then stop.
12) Driver's side:
turn the star wheel CLOCKWISE
until the shoes are against the rotor hat. Turn the star wheel COUNTER CLOCKWISE
4 - 5 points or notches, then stop.
13) Apply the parking brake lever and make sure it stops within 4 - 8 clicks. Release brake lever.
14) Install the rubber access plug, brake calipers, and sway bar links (if removed). Torque caliper bolts to 50 ft lbs and sway bar link hardware to 37 ft lbs.
15) Install wheels and torque to 95 ft lbs.
Enjoy your working parking brake!