Procedures

BRAKE DRUM MACHINING

If 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 (2) are marked with the maximum allowable brake drum diameter. All vehicles have it marked on the inside of the drum (1).

When machining, make sure the feed rate for the final cut is set to deliver a fine finish. A fine finish helps 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.