Brake Shoe: Service and Repair
^ TOOLS REQUIRED- J 21177-A Brake Shoe Setting Toot
NOTICE: When installing new brake drums, do not refinish the braking surface as these parts are at the correct level of surface finish.
DISASSEMBLY
1. Release park brake.
CAUTION: MAKE SURE VEHICLE IS PROPERLY SUPPORTED AND SQUARELY POSITIONED ON HOIST.
2. Raise vehicle on hoist.
3. Remove rear wheel and tire assembly.
4. Remove brake drum retaining screw
NOTICE: Do not pry against brake backing plate. This will bend plate.
5. Remove rear drum.
IMPORTANT: If difficulty is encountered removing drum, the following steps apply.
^ Insert a screwdriver in access hole and push park brake lever toward outside of drum to release shoes from adjuster.
^ Remove brake drum.
NOTICE: Do not over extend spring. Over extending spring will weaken it.
6. Remove upper return spring.
7. Remove upper return spring retaining bracket.
8. Detach adjuster lever with spring.
9. Pull brake shoes apart slightly and remove adjuster unit.
10. Remove brake shoe hold down springs and pins.
11. Remove leading (front) brake shoe and detach trailing (rear) brake shoe from park brake cable and remove.
12. Disassemble brake adjuster components: adjusting socket, screw, then clip, and nut.
13. Clean adjusting socket, screw, and nut in clean denatured alcohol.
14. Inspect adjuster assembly, making sure that adjuster screw threads smoothly into adjusting nut, over full threaded length.
NOTICE: If wheel cylinder is found to be damaged, replace it. Do not attempt to repair wheel cylinder.
15. Inspect wheel cylinder for leakage and cut or damaged boots. Also, make sure that wheel cylinder is not seized.
ASSEMBLY
IMPORTANT: When replacing rear brake shoes, inspect backing plate for excessive wear at six raised shoe contact pads. Excessive wear at raised shoe contact pads, such as notches or deep grooves, could impede shoe travel.
IMPORTANT: Never replace brake shoes/linings on one side of axle only. Brake shoes/linings must be replaced as axle sets.
1. Lubricate the following components:
^ Adjuster lever surfaces that rub on brake shoe web.
^ Backing plate at the six raised shoe contact pads.
2. Install park brake cable to park brake lever of trailing (rear) brake shoe.
3. Install trailing (rear) brake shoe to backing plate using hold down pin and retaining spring.
4. Attach lower retaining spring and install leading (front) brake shoes, hold down pin, and retaining spring.
5. Slightly pull apart brake shoes and install adjuster unit.
6. Install adjuster lever with spring.
NOTICE: Check that brake shoe is correctly engaged in wheel cylinder at top and anchor at bottom.
NOTICE: Check that adjuster notches properly engage in brake shoe notches.
7. Install retaining bracket and install upper return spring.
8. Using a 165 - 368 mm (6.5 - 14.5 inch) caliper such as J21177-A (or equivalent), measure inside diameter of brake drum.
Rear Drum Diameter
New 230.0 mm (9.05 inch)
Maximum refinish/diameter 230.65 mm (9.08 inch)
Discard 231 mm (9.09 inch)
IMPORTANT: Refer to "Inspecting and Refinishing Brake Drums".
9. Measure outside diameter of brake shoes and adjust brake adjuster to obtain 0.50 mm (0.020 inch) less than the reading obtained in previous step.
10. Install brake drum and retaining screw.
Torque: 4 Nm (35 inch lbs.)
11. Bleed brakes if new wheel cylinder or backing plate was installed.
NOTICE: Before installing wheels, remove rust or corrosion from wheel mounting surfaces and brake rotors/drums. Failure to do so can cause wheel bolts. to loosen in service.
12. Position wheel and tire assembly onto hub.
13. Install wheel bolts and tighten in a crisscross pattern. Repeat tightening pattern to be sure torque is correct.
Torque: 125 Nm (92 inch lbs.)
14. Lower vehicle from hoist.
CAUTION: IF THIS OPERATION IS NOT CARRIED OUT, BRAKES WILL NOT OPERATE DURING INITIAL BRAKE APPLICATIONS.
15. Apply and release brake pedal 20 times to allow adjuster to position brake shoes.
16. Adjust park brake cable.