Brake Drum: Testing and Inspection

Any time you remove the brake drums, thoroughly clean and inspect them for cracks, scores, deep grooves, and out-of-round.

SURFACE FINISH
Slight scoring can be cleaned up with fine emery cloth. Heavy or extensive scoring causes excessive lining wear. The drum braking surface will need machining to remove these scores. If the drum is grooved and the brake linings are slightly worn, the drum should not be machined. Instead, polish the drum braking surface with Me emery cloth. Eliminating all of the drum grooves and ridges on the lining would require removing too much metal and lining material. The grooves and ridges match and satisfactory service can be obtained by leaving them alone.

INSIDE DIAMETER CHECK
Measure the inside diameter of the brake drum at two or more places around the circumference of the braking surface. The measurements must be made at the same distance in from the edge of the drum. Compare the results with the wear specifications.

TAPER CHECK
Measuring a drum for taper involves taking measurements at the inner and outer edges of the machined surface at two or more places around the drum. These measurements should be equal.