Brake Rotor Assembled Lateral Runout (LRO) Measurement

Brake Rotor Assembled Lateral Runout (LRO) Measurement

Tools Required
^ J 41013 Rotor Resurfacing kit
^ J 42450-A Wheel Hub Resurfacing Kit
^ J 45101 Hub and Wheel Runout Gage
^ J 45101-100 Conical Brake Rotor Washers

Important:
^ Brake rotor assembled lateral runout (LRO) exceeding the maximum allowable specification can cause thickness variation to develop in the brake rotor over time, usually between 4800-11300 km (3,000-7,000 mi).
^ Measure brake rotor thickness variation BEFORE measuring LRO. Thickness variation exceeding the maximum specification can cause brake pulsation.

1. Measure the brake rotor thickness variation. Refer to Brake Rotor Thickness Variation Measurement. Brake Rotor Thickness Variation Measurement
2. Use paint in order to mark the position of the brake rotor to the wheel studs.
3. Remove the brake rotor from the vehicle. Refer to Brake Rotor Replacement - Front or to Brake Rotor Replacement - Rear as applicable. Service and Repair

Important: Clean any rust or contaminants from the hub flange and the brake rotor mating surfaces. Failure to do this may result in excessive LRO of the brake rotor, which could lead to brake pulsation.

4. Inspect the mating surface of the hub flange and the brake rotor. If rust or foreign particles are on the hub flange or the brake rotor mating surfaces, perform the following steps:
4.1. Use the J 42450-A in order to thoroughly clean any rust or contaminants from the mating surface of the hub flange.
4.2. Use the J 41013 in order to thoroughly clean any rust or contaminants from the mating surface of the brake rotor.
4.3. Clean the friction surfaces of the brake rotor with denatured alcohol or an equivalent approved brake cleaner.
5. Align the paint marks and install the rotor to the hub flange.
6. Hold the rotor firmly in place against the hub flange. Install one of the J 45101-100 and one wheel nut onto the upper-most wheel stud.
7. Continue to hold the rotor secure and tighten the wheel nut firmly by hand.
8. Install the remaining J 45101-100 and the wheel nuts onto the wheel studs and tighten the nuts firmly by hand in a star-pattern.
9. Tighter the wheel ruts in order to retain the rotor to the hub. Refer to Fastener Tightening Specifications in Tires and Wheels.
10. Perform the following steps in order to measure and record the assembled LRO of the brake rotor.
10.1. Install the J 45101, or equivalent. Position the indicator button so it contacts the brake rotor friction surface 10 mm (0.39 in) from the outer edge of the rotor.
10.2. Verify the indicator is at a 90 degree angle to the brake rotor.
10.3. Rotate the rotor until the indicator dial displays the lowest reading.
10.4. Set the dial to zero.
10.5. Rotate the rotor until the indicator dial displays the highest reading.
10.6. Mark the location of the high spot relative to the nearest wheel stud or studs.
10.7. Measure and record the amount of LRO.
11. Compare the brake rotor assembled LRO to the following specification:
Specification
^ Front brake rotor maximum allowable assembled lateral runout: 0.05 mm (0.002 in)
^ Rear brake rotor maximum allowable assembled lateral runout: 0.15 mm (0.006 in)
12. If the LRO measurement is within the specification, complete the following steps:
12.1. Remove the J 45101
12.2. Install the brake caliper.
12.3. Press the brake pedal several times in order to position the rotor.
12.4. Remove the wheel nuts.
12.5. Remove the J 45101-100.
12.6. Install the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
13. IF the LRO measurement EXCEEDS the specification and you REFINISHED or REPLACED the rotor, adjust the LRO. Refer to Brake Rotor Assembled Lateral Runout (LRO) Correction.
14. If the LRO measurement EXCEEDS the specification and you DID NOT refinish or replace the rotor, refinish the rotor in order to attain true parallelism. Refer to Brake Rotor Refinishing.
15. Measure the LRO in order to verify the rotor is within the specification.