Commander 2WD V8-4.7L (2008)
Brake Rotor/Disc: Testing and Inspection
Diagnosis and Testing - Front
FRONT
ROTOR MINIMUM THICKNESS
Rotor minimum usable thickness is 28.5 mm (1.122 in.). Do not resurface a rotor if machining would cause thickness to fall below this limit.
Measure rotor thickness at the center of the brake shoe contact surface. Replace the rotor if worn below minimum thickness, or if refinishing would
reduce thickness below the allowable minimum.
FRONT ROTOR THICKNESS VARIATION
Variations in rotor thickness will cause pedal pulsation, noise and shudder.
Measure rotor thickness a minimum of six points around the rotor face. Position the micrometer approximately 19 mm (3/4 in.) from the rotor outer
circumference for each measurement.
Thickness should not vary by more than 0.0127 mm (0.0005 in.) from point to point on the rotor. Refinish or replace the rotor if necessary.
NOTE: A hub mounted on-vehicle lathe is recommended. This type of lathe trues the rotor to the vehicles hub/bearing.
Front rotors and hub/bearings are matched mounted for minimum lateral runout. Before removing the rotor, mark the rotor and hub/bearing to maintain
original orientation.
FRONT ROTOR LATERAL RUNOUT
Check rotor lateral runout whenever pedal pulsation, or rapid, uneven brake lining wear has occurred.
The rotor must be securely clamped to the hub to ensure an accurate runout measurement. Secure the rotor with a minimum of 3 lug nuts and large
diameter flat washers on each stud.
Use a dial indicator to check lateral runout.
Maximum allowable rotor lateral runout is 0.05 mm (0.002 in.).
