A cracked drum is unsafe for further service and must be replaced. Do not attempt to weld a cracked drum.

Smooth up any light scores. Heavy or extensive scoring causes excessive lining wear and it may be necessary to resurface the drum braking surface.

If the linings are slightly worn (but still re-usable) and the drum is grooved, polish the drum with a fine emery cloth but do not refinish the drum. Eliminating all grooves in the drum and smoothing the ridges on the lining would require removing too much metal and lining. If left alone, the grooves and ridges match and satisfactory service can be obtained.

Always refinish a grooved drum when replacing the brake linings. Using a grooved drum with new linings will wear the linings. This may cause improper brake performance.

An out-of-round or tapered drum prevents accurate brake shoe adjustment and is likely to cause excessive wear of other brake parts due to its eccentric action. An out-of-round drum can also cause severe and irregular tire tread wear as well as a pulsating brake pedal. The drums should be refinished if taper or out-of-roundness exceeds 0.015  mm (0.006  in). Out-of-round and taper can be accurately measured with an inside micrometer and extension rods. When measuring a drum for an out-of-round and taper, take measurements at the open and closed edges of the machined surface and at right angles to each other. When the drum exceeds the specification limits in taper and/or out-of round, refinish the drum in order to true-up the braking surface.