Brake Rotor Assembled Lateral Runout (LRO) Measurement

Front Rotor

^ Tools Required
- J 8001 Dial Indicator Set

Lateral runout is the movement of the rotor braking surface from side to side as the rotor turns, this could be described as ROTOR WOBBLE. The movement of the rotor from side to side in the lateral plane knocks the brake pads away from the brake rotor. This will cause the piston to be driven back into the caliper. This can result in excessive brake pedal travel and possible vibrations or pulsation during braking. Pulsation due to front brake rotor lateral runout is noticeable through the steering wheel.

1. Remove the front brake caliper. Refer to Brake Caliper Replacement - Front.
2. Install a wheel bolt (2) to the rotor opposite the rotor set screw (1) so the rotor is held tight against the hub.
3. Fasten J 8001 to the steering knuckle so that the dial indicator button contacts the rotor braking surface about 13 mm (0.5 inches) from the outer diameter of the rotor.
4. Zero J 8001.
5. Turn the rotor one complete revolution and observe the Total Indicted Runout (TIR).
^ TIR should not be more than 0.10 mm (0.004 inch).
^ A brake rotor that does not meet the lateral runout specification should be resurfaced or replaced as necessary.
6. Install the brake caliper. Refer to Brake Caliper Replacement - Front.

Rear Rotor

^ Tools Required
- J 8001 Dial Indicator Set

1. Remove the brake caliper. Refer to Brake Caliper Replacement - Rear.





2. Install a wheel bolt (2) to the rotor opposite the rotor set screw (1) so the rotor is held tight against the hub.





3. Fasten the J 8001 to the rear brake caliper bracket so that the dial indicator button contacts the rotor braking surface about 13 mm (0.5 inches) from the outer diameter of the rotor.
4. Push in the wheel bearing hub to minimize endplay while setting the J 8001 to zero.
5. Push in the wheel bearing hub to minimize wheel bearing hub endplay while turning the rotor one complete revolution.
6. Observe the Total Indicated Runout (TIR). The TIR should not be more than 0.10 mm (0.004 inches).
7. Check the wheel bearing hub flange for excessive lateral runout or for looseness if the lateral runout of the rotor still exceeds 0.10 mm (0.004 inches). Refer to Tire and Wheel Runout Specifications.
8. Install the brake caliper. Refer to Brake Caliper Replacement - Rear.