Lateral Runout Check

The best way to check lateral runout is with the wheels still installed on the vehicle. This gives a more accurate reading of the total indicated runout (TIR) under actual braking conditions. If you do not have the equipment to do the check with the wheels installed, the next best reading can be made with the wheels removed but with the caliper still installed.

Important: If you must remove the wheel, re-install the wheel nuts in order to retain the rotor. Tighten the wheel nuts per specification in Tires and Wheels.

1. Clean the rotor surface.
2. Fasten a dial indicator to the steering knuckle so that the indicator button contacts the rotor surface about 13 mm (1/2 inch) from the outer edge.
3. Turn the dial indicator to zero.

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.

4. Move the wheel (or rotor) one complete revolution, and check the total indicated runout (TIR). TIR must not exceed 0.06 mm (0.002 inch).

•	In some cases, excessive lateral runout can 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, check the hub and bearing for excessive lateral runout, or looseness.

-	If the hub and bearing exceeds 0.040 mm (0.0015 inch), replace the hub and bearing.

-	If lateral runout is within specifications, refinish or replace the rotor, as needed.

5. If the lateral runout exceeds the amount specified in step 4, refinish or replace the rotor, as needed.