Brake Shoe: Service and Repair
Rear Brake Disassembly and Assembly
Disassembly
CAUTION: MAKE SURE VEHICLE IS PROPERLY SUPPORTED AND SQUARELY POSITIONED ON HOIST or Stands. TO HELP AVOID PERSONAL INJURY PROVIDE ADDITIONAL SUPPORT TO THE OPPOSITE END OF THE VEHICLE THAT COMPONENTS WILL BE REMOVED FROM.
1. Release park brake.
2. Raise vehicle.
3. Remove rear road wheel(s).
4. Remove brake drum.
NOTICE: Do not pry against brake backing plate. This will bend plate. If difficulty is encountered removing drum, use drum brake adjusting tool SA92O1BR or equivalent, to turn star wheel of adjuster assembly to shorten its length and provide sufficient drum-to-shoe clearance for drum removal.
5. Remove lower return spring.
NOTICE: Don't over extend spring. This will weaken it.
6. Remove adjuster spring.
7. Remove leading shoe hold down cup, spring, and pin.
5. Remove lower return spring.
6. Remove adjuster spring.
7. Remove leading shoe hold down cup, spring, and pin.
8. Remove adjuster assembly and adjuster lever. If difficulty is encountered, proceed as follows:
a. Pull leading shoe towards front of vehicle, freeing adjuster assembly. Remove assembly.
b. If necessary turn star wheel on adjuster to shorten its length.
9. Remove leading shoe by twisting shoe out of engagement with upper return spring.
10. Remove upper return spring from park brake shoe.
11. Remove park brake shoe hold down cup, hold down spring, and hold down pin.
12. Remove park brake cable from park brake lever by pushing lever into cable spring. Simultaneously, disengage cable end from lever.
13. Remove park brake shoe (along with park brake lever and cable spring).
14. Remove park brake lever retainer and wave washer, and separate lever from park brake shoe.
15. Disassemble brake adjuster components: adjusting socket, screw, and nut.
16. Clean adjusting socket, screw, and nut in clean, denatured alcohol.
17. Inspect adjuster assembly, making sure that the adjuster screw threads smoothly into the adjusting nut, over the full threaded length.
18. Inspect wheel cylinder for leakage and cut or damaged boots. Also, make sure that wheel cylinder is not seized.
IMPORTANT: If wheel cylinder is found to be damaged, replace it. Do not attempt to repair wheel cylinder.
Assembly
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 with brake lubricant:
a. Adjuster assembly. Apply to threads of screw and inner diameter face of socket.
b. Adjuster lever surfaces that rub on brake shoe web.
c. Backing plate at the six raised shoe contact pads.
d. Park brake lever pin and surfaces that contact brake shoe web.
2. Install park brake lever assembly onto pin on park brake shoe and secure with wave washer and retainer clip making sure to crimp ends of retainer securely to retain park brake lever.
3. Only if cable spring was removed: Install cable spring into cage on park brake lever.
4. Install park brake cable, through the cable spring, onto the park brake lever.
5. Install park brake shoe by positioning shoe and installing hold down pin, hold down spring and hold down cup.
NOTICE: Check that brake shoe is correctly engaged (in wheel cylinder on top, anchor on bottom).
6. Install long, straight end of upper return spring into back of hole in park brake shoe.
7. Install other end of upper return spring into the back of the leading brake shoe. Stretch spring to correctly position the leading shoe on the backing plate.
NOTICE: Check that brake shoe is correctly engaged (in wheel cylinder on top, anchor on bottom).
8. Pull leading shoe toward front of vehicle and install adjuster assembly between park and leading brake shoes.
NOTICE: Check that adjuster notches properly engage in the brake shoe notches.
9. Install adjuster lever.
NOTICE: Check that notch on adjuster lever engages pin on park brake shoe and notch on adjusting socket.
NOTICE: Check that lower leg of adjusting lever engages teeth of star wheel on adjuster assembly.
10. Install leading brake shoe by positioning shoe and installing hold down pin, hold down spring and hold down cup.
NOTICE: Check that brake shoe is correctly engaged (in wheel cylinder on top, anchor on bottom).
11. Install adjuster spring by placing short end of adjuster spring into hole in leading shoe and stretching other end of spring into hole in adjuster lever.
12. Install lower return spring by hooking one end of spring into hole of one shoe and stretching other end of spring into hole of other shoe.
13. Check assembly for correct location and installation of springs and components.
14. Using a 0-200 mm (0-8 in.) caliper such as SA921O9NE (or equivalent), measure the inside diameter of brake drum.
15. Measure outside diameter of brake shoes and adjust brake adjuster to obtain 0.50 mm (0.020 in.) less than the reading obtained in step 14.
16. Install brake drum.
17. Bleed brakes if new wheel cylinder or backing plate has been installed.
NOTICE: Before installing wheels, remove rust or corrosion from wheel mounting surfaces and brake rotors/drums. Failure to do so can cause wheel lug nuts to loosen in service.
18. Position wheel onto hub.
19. Install wheel nuts and tighten in a crisscross pattern. Repeat tightening pattern to be sure torque is correct.
Torque: 140 Nm (103 ft.lbs.)
20. Lower vehicle.
21. Apply and release brake pedal 20 times to allow adjuster to position brake shoes.
22. Adjust park brake refer to "Park Brake Adjustment."