Grand Cherokee 2WD V6-3.7L (2008)
Brake Rotor/Disc: Testing and Inspection
Diagnosis and Testing - Rear
REAR
ROTOR MINIMUM THICKNESS
Minimum usable thickness of the rear disc brake rotor is 12.5 mm (0.492 in.). The thickness specification is located on the center section of the rotor.
Never 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.
REAR ROTOR THICKNESS VARIATION
Variations in rotor thickness will cause pedal pulsation, noise and shudder.
Measure rotor thickness at 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.
REAR ROTOR LATERAL RUNOUT
Check rotor lateral runout whenever diagnosis indicates pedal pulsation and rapid, uneven brake lining wear.
The rotor must be securely clamped to the hub to ensure an accurate runout measurement. Secure the rotor with the wheel nuts and 4 or 5 large diameter
flat washers on each stud.
Use a dial indicator to check lateral runout. Maximum allowable lateral runout is 0.02 mm (0.00079 in.).
