Cherokee 4WD L6-4.0L VIN S (1998)
Brake Drum: Testing and Inspection
GENERAL INFORMATION
The maximum allowable diameter of the drum braking surface is stamped or cast into the drum outer edge. Generally, a drum can be machined to
a maximum of 1.52 mm (0.060 inch) oversize. Always replace the drum if machining would cause drum diameter to exceed the size limit
indicated on the drum.
BRAKE DRUM RUNOUT
Measure drum diameter and runout with an accurate gauge. The most accurate method of measurement involves mounting the drum in a brake
lathe and checking variation and runout with a dial indicator.
Variations in drum diameter should not exceed 0.076 mm (0.003 inch). Drum runout should not exceed 0.20 mm (0.008 inch) out of round.
Machine the drum if runout or variation exceed these values. Replace the drum if machining causes the drunk to exceed the maximum allowable
diameter.
