When you remove the drum brake, thoroughly clean and inspect the drum for the following problems:
| • | Cracks |
| • | Deep grooves |
| • | Scores |
| • | Out-of-round |
Surface Finish
Slight scoring can be cleaned up with a fine emery cloth. Heavy or extensive scoring causes excessive brake 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, do not machine the drum. Instead, polish the drum braking surface with a fine emery cloth. Eliminating all of the drum grooves and the ridges on the lining would require removing too much metal and lining material. The grooves and the 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.
Taper Check
Measuring a drum for taper involves taking measurements at the inner and the outer edges of the machined surface at two or more places around the drum. These measurements should be equal.
