LW300 V6-3.0L VIN R (2001)
Brake Drum: Service and Repair
Inspecting and Refinishing Brake Drums
INSPECTING AND REFINISHING BRAKE DRUMS
Whenever brake drums are removed, they should be thoroughly cleaned and inspected for cracks, scores, deep grooves, and roundness.
CRACKED, SCORED, OR GROOVED DRUMS
A cracked drum is unsafe for further service and must be replaced. Do not attempt to weld a cracked drum.
Light scoring of the drum surface not exceeding 1.0 mm (0.040 inch) in depth, which may result from normal use, is not detrimental to brake
operation.
A drum with a grooved surface finish can be reconditioned using 80 grade sandpaper with drum mounted and rotating on a brake lathe. An
inboard/outboard sanding motion will produce a multi-directional finish on drum.
OUT-OF-ROUND
An out-of-round drum makes accurate brake pad adjustment impossible and is likely to cause excessive wear of other parts of brake mechanisms due
to its eccentric action. An out-of-round drum can also cause severe and irregular tire wear as well as a pulsating brake pedal. When drum exceeds
out-of-round specification limits, the drum should be refinished or replaced.
Drum roundness can be accurately measured with an inside micrometer, fitted with proper extension rods.
When measuring a drum for out-of-round, take measurements at right angles (90 degrees) to each other.
