Brake System Diagnosis Drum Inspection
Clean and inspect the brake drum any time the brake drum
is removed. Check the brake drum for the following conditions:
Surface Finish
Light scoring can be cleaned up with a fine emery cloth. Heavy or extensive
scoring causes excessive lining wear. The drum braking surface will need machining
in order 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
a fine 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. Measure at the same distance
in from the edge of the drum. Compare the results with the wear specifications.
Taper Check
Check the drum taper by measuring at the inner and outer edges of the
machined surface. Measure at two or more places around the drum.
Brake System Diagnosis Lining Inspection
| • | Inspect the brake linings every 10 000 km (6,000 miles)
and any time the wheels are removed. |
| • | Replace bonded brake shoe and lining assemblies when the thickness
of any lining is worn within 0.76 mm (0.030 in) of the shoe. |
| • | Replace riveted shoe and lining assemblies when the thickness
of any lining is worn within 0.76 mm (0.030 in) of any rivet
head. |
| • | Always replace disc brake shoe and lining assemblies as a complete
axle set. |
