Lateral Runout

Excessive lateral, or side-to-side, runout of the rotor surface may result in a vehicle vibration during braking. In some cases, this vibration may not be felt in the brake pedal. To inspect for lateral runout, it is necessary to use a dial indicator as described in the following procedure:
1. Remove the wheel and tire assembly and install at least three lug nuts to hold the rotor on the hub and bearing assembly.
2. Using either a magnetic mount or clamp mount, position the dial indicator so that the indicator stylus contacts the rotor surface approximately 25mm (1 inch) from the rotor edge. The dial indicator should be mounted on the caliper mounting bracket or suspension knuckle for best results.
3. Zero the dial indicator.
4. Move the rotor through at least one complete revolution and observe the total indicated runout TIR.
5. Lateral runout of the rotor, if excessive, can often be improved by indexing the rotor on the hub one or two bolt positions from the original position. If the lateral runout marmot be corrected by indexing the rotor, check the hub and bearing assembly for excessive lateral runout. If the hub flange runout exceeds 0.06 mm (0.002 inch), replace the hub and bearing assembly.

NOTE: Rotors diagnosed as having lateral runout exceeding the specifications should be refinished or replaced if minimum thickness specifications cannot be met.