Brake Drum: Service and Repair
DISASSEMBLYLeft side shown; right side opposite.
1. Release park brake.
CAUTION: MAKE SURE VEHICLE IS PROPERLY SUPPORTED AND SQUARELY POSITIONED ON HOIST. TO HELP AVOID PERSONAL INJURY, PROVIDE ADDITIONAL SUPPORT TO THE OPPOSITE END OF THE VEHICLE THAT COMPONENTS WILL BE REMOVED FROM.
2. Raise vehicle on hoist.
3. Remove rear road wheel(s).
4. Remove brake drum.
NOTICE: Do not pry against brake backing plate. This will bend plate.
IMPORTANT: If difficulty is encountered removing drum, use drum brake adjusting tool SA9201BR or equivalent to turn star wheel adjuster assembly to shorten its length to provide sufficient drum-to-shoe clearance for drum removal.
Fig. 1 Rear Brake Assembly:
5. Remove lower return spring.
NOTICE: Do not over extend springs. Over extending will weaken the spring(s).
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, while at the same time disengaging 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 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: When replacing the rear brake shoes, inspect the backing plate for excessive wear at the six raised shoe contact pads. Excessive wear at the raised shoe contact pads, such as notches or deep grooves, could restrict 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:
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.
IMPORTANT: Make sure to crimp ends of retainer securely to retain park brake lever.
3. Install cable spring into cage on park brake lever only if cable spring was removed.
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.
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 inch) caliper such as SA92109NE (or equivalent), measure the inside diameter of brake drum.
Rear Drum Diameter
New 200.0 mm (7.87 inch)
Maximum after Turning 200.6 mm (7.90 inch)
Discard 201.4 mm (7.93 inch)
IMPORTANT: Refer to "Inspecting and Refinishing Brake Drums". Testing and Inspection
15. Measure outside diameter of brake shoes and adjust brake adjuster to obtain 0.50 mm (0.020 inch) 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 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 from hoist.
21. Apply and release brake pedal 20 times to allow adjuster to position brake shoes.
22. Adjust park brake.