Drum Brake System: Service and Repair

NOTICE: Hydraulic will damage paint. If fluid gets on a painted surface, wipe off immediately.

REMOVAL





1. Loosen the five wheel lug nuts.
2. Raise vehicle and support the frame.
3. Remove front wheel.
4. Set the parking brake.
5. Loosen and remove the four hub nuts and screws.





6. Release parking brake and remove wheel drum.
7. Remove the adjuster lever spring with a spring wrench or pliers and then remove the adjuster lever.





8. Remove the return spring with a brake spring wrench or pliers.





9. Turn the adjuster star wheel clockwise to relieve tension on the shoes.





10. Remove the adjuster assembly.
11. Turn the hold-down pins until they align with the groove in the hold-down spring clips.
12. Remove hold-down pins and spring clips.





13. Remove primary shoe and anchor spring.
14. Remove the secondary brake shoe with parking brake cable attached, then remove parking brake cable from shoe.






15. Remove control lever C-clip and lever from secondary brake shoe.






16. Disconnect brake line from wheel cylinder.
17. Remove the two wheel cylinder mounting bolts and remove wheel cylinder.





18. Remove parking brake cable bracket bolt, then remove parking brake cable from backing plate.





19. Remove four nuts from backing plate.
20. Tap axle from behind with rubber hammer and then remove axle from housing.
21. Remove backing plate.

INSPECTION

1. Check for cracks, scores grooves or abnormal wear on the inner surface of the drum.
2. Measure the inner diameter of the drum. Verify that the drum interior is circular.
Maximum acceptable: 9.89 inch (251.2 mm)





3. If damaged or out of round, but within maximum diameter, turn the drum to repair.

CAUTION: If you replace one set of shoes, you must replace the other set To do otherwise will affect the uniformity of the rear brakes.

4. Check for damage to or abnormal wear of the brake shoes.





5. Measure the thickness of the lining.

New thickness: 0.24 inch (6.0 mm)
Minimum thickness: 0.06 inch (1.5 mm)





6. Check clearance between the drum and the ends of the brake shoes. If contact is poor, replace the shoes.

INSTALLATION





1. Place backing plate on axle housing.
2. Grease axle and insert it into the axle housing.
3. Insert and tighten the four backing plate nuts.
Tighten nuts to 73 ft. lbs. (98.3 Nm)
4. Install parking brake cable in backing plate, then insert and tighten the bolt in cable mounting bracket.
5. Install wheel cylinder and tighten the two mounting bolts.
Apply a sealant (RTV silicone) around the wheel cylinder mounting holes.
Tighten bolts to 115 inch lbs. (13 Nm)
6. Apply grease to wheel cylinder contacts points.





7. Install brake line to wheel cylinder.
Tighten line nut to 89 inch lbs. (10 Nm)





8. Install control lever on secondary shoe with new C-clip.
9. Connect the parking brake cable to secondary shoe with pliers.





10. Attach secondary shoe to backing plate with the hold down pin and spring clip.
11. Attach one end of anchor spring to secondary shoe and the other to primary shoe.
12. Position primary shoe and install hold down pin and spring clip.





13. Install adjusting assembly.
14. Install return spring with spring wrench.
15. Install adjusting lever and adjusting lever spring.





NOTICE: The adjusting lever must contact the star wheel on the adjuster assembly.





16. Measure outer shoe diameter when installed on drums.
17. Measure the drum's inner diameter.
18. Calculate clearance by subtracting shoe diameter from drum diameter. Adjust by turning star wheel on adjusting assembly.





19. Install drum and set parking brake.
10. Install and tighten the three hub bolts.
21. Release parking brake and install tire and loosely tighten lug nuts.
22. Lower vehicle and then tighten lug nuts.





23. Add brake fluid and bleed brakes.
24. Check for fluid leakage.