Brake Rotor Assembled Lateral Runout (LRO) Correction

Brake Rotor Assembled Lateral Runout (LRO) Correction

Important:
- Brake rotor thickness variation MUST be checked BEFORE checking for assembled Lateral Runout (LRO). Thickness variation exceeding the maximum acceptable level can cause brake pulsation.
- 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 4,800 - 11,300 km (3,000 - 7,000 mi).
- Review the following acceptable methods for bringing the brake rotor assembled LRO to within specifications. Determine which method to use for the specific vehicle being repaired.
- The indexing method of correcting assembled LRO is most effective when the LRO specification is only exceeded by a relatively small amount: 0.025 - 0.127 mm (0.001 - 0.005 inch). Indexing is used to achieve the best possible match of high spots to low spots between related components.
- The correction plate method of correcting assembled LRO involves the addition of a tapered plate between the brake rotor and the hub/axle flange. The correction plate method can be used to correct LRO that exceeds the specification by up to 0.23 mm (0.009 inch).
- The on-vehicle brake lathe method is used to bring the LRO to within specifications through compensating for LRO while refinishing the brake rotor.
- If the assembled LRO cannot be corrected using these methods, then other components must be suspected as causing and/or contributing to the LRO concern.