Brake Rotor Assembled Lateral Runout (LRO) Measurement

NOTICE: Whenever the brake rotor has been separated from the wheel bearing flange, clean any rust or foreign material from the mating surface of the rotor and flange with the J 42450 hub cleaning kit. Failure to do this may result in increased lateral runout of the rotor and brake pulsation.

Inspect the lateral runout with the wheels on the vehicle in order to get a more accurate reading of the Total Indicated Runout (TIR) under real braking conditions. If the equipment is not available to perform the check with the wheels on the vehicle, remove the wheels with the caliper in place in order to get an accurate reading.

REMOVAL PROCEDURE

^ Tools Required
- J 8001 Dial Indicator Set

1. Raise and suitably support the vehicle.
2. Mark the relationship of the wheel to the hub.
3. Remove the tire and the wheel.
4. Clean the rotor surface.
5. Reinstall the wheel nuts in order to retain the rotor.
6. Fasten the J 8001 to the steering knuckle. Ensure that the indicator button contacts the rotor surface about 13 mm (0.500 inch) from the outer edge.
7. Set the dial indicator to zero.
8. Turn the wheel one complete revolution. Inspect the runout indicated on the dial. If the TIR exceeds 0.080 mm (0.003 inch), refinish or replace the rotor.

In some cases, excessive lateral runout of the rotor may be improved by indexing the rotor on the hub, one or two bolt positions from the original position. If the lateral runout cannot be corrected by indexing the rotor, then inspect the hub for excessive lateral runout or looseness. If the hub lateral runout exceeds 0.040 mm (0.015 inch), replace the hub. If lateral runout is within specifications, refinish or replace the rotor as necessary.


INSTALLATION PROCEDURE
1. Remove the wheel nuts securing the rotor to the hub.
2. Install the tires and wheels. Align the previous marks on the wheel and the hub.
3. Lower the vehicle.