Brake Drum: Service and Repair
STANDARD PROCEDURE - BRAKE DRUM MACHININGIf a brake drum is deeply scored or warped, it can be machined on a brake lathe equipped to machine brake drums. Follow the manufacturers instructions on the machining procedure.
Measure the brake drum diameter before machining. If machining the drum will cause the drum to exceed maximum allowable diameter, do not machine the brake drum. It needs to be replaced.
CAUTION: Do not machine the brake drum if it will cause the drum to exceed maximum allowable diameter.
All brake drums are marked with the maximum allowable brake drum diameter (Fig. 87).
When machining, make sure the final finish feed cut is fine in order to avoid a screw effect on the brake shoes when the brakes are applied. This final feed cut specification varies from lathe manufacturer to lathe manufacturer.
REMOVAL
1. Raise the vehicle.
2. Remove the rear tire and wheel assembly from the vehicle
3. Remove the brake drum retaining clips (if equipped) (Fig. 88).
4. Remove the brake drum (Fig. 88).
NOTE: If the drum does not come off, further brake clearance can be obtained by backing off the brake automatic adjuster screw. Remove the rubber plug from the top of brake support plate. Rotate the automatic adjuster screw in an upward motion, using a screwdriver.
INSTALLATION
NOTE: Before installing the drum, inspect the brake shoe linings for wear, shoe alignment, and contamination.
1. Install the rear brake drum on rear hub and bearing (Fig. 88).
2. Install the tire and wheel assembly. Tighten the wheel mounting nuts to a torque of 135 Nm (100 ft. lbs.).
3. Adjust the rear brake shoes as necessary.
4. Lower the vehicle.