LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 187 (Disc Brakes) >> Adjustments & Inspections >> Brake Rotor Assembled Lateral RUNOUT (LRO) Measurement

Brake Rotor Assembled Lateral RUNOUT (LRO) Measurement

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Savana Special, 2003 GMC Savana Camper Special, 2003 GMC Savana, 2003 Chevrolet RV Cutaway, and 2003 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Required Tools: Torque-Limiting Socket Set, or equivalent (J-39544-KIT), Rotor Resurfacing Kit (J-41013), Wheel Hub Resurfacing Kit (J-42450-A), Hub and Wheel Runout Gage (J-45101) and Conical Brake Rotor Washers (J-45101-100).
NOTE: Whenever the brake rotor has been separated from the hub/axle flange, any rust or contaminants should be cleaned from the hub/axle flange and the brake rotor mating surfaces. Failure to do this may result in excessive assembled lateral runout (LRO) of the brake rotor, which could lead to brake pulsation.
NOTE: 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 3,000-7,000 mi (4800-11300 km).
NOTE: 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. See BRAKE ROTOR THICKNESS VARIATION MEASUREMENT  .
  1. Matchmark the position of the brake rotor to the wheel studs if this has not been done already.
  2. Inspect the mating surface of the hub/axle flange and the brake rotor to ensure that there are no foreign particles, corrosion, rust, or debris remaining. If the wheel hub/axle flange and/or if the brake rotor mating surfaces exhibit these conditions, perform the following steps:
    1. Remove the brake rotor from the vehicle. See BRAKE ROTORS  under REMOVAL & INSTALLATION.
    2. Using the Wheel Hub Resurfacing Kit, thoroughly clean any rust or corrosion from the mating surface of the hub/axle flange.
    3. Using the Rotor Resurfacing Kit, thoroughly clean any rust or corrosion from the mating surface of the brake rotor.
    4. Clean the friction surfaces of the brake rotor with denatured alcohol, or an equivalent approved brake cleaner.
  3. Install the rotor to the hub/axle flange using the matchmark made prior to removal.
  4. Hold the rotor firmly in place against the hub/axle flange and install one of the Conical Brake Rotor Washers, and one lug nut onto the upper-most wheel stud.
  5. Continue to hold the rotor secure and tighten the lug nut firmly by hand.
  6. Install the remaining Conical Brake Rotor Washers and lug nuts onto the wheel studs and tighten the nuts firmly by hand in a star-pattern.
  7. Using the Torque-Limiting Socket Set, or equivalent, tighten the lug nuts in a star-pattern to specification, in order to properly secure the rotor.
  8. If the brake rotor has been REFINISHED or REPLACED with a new rotor, proceed to step  14 .
  9. If the brake rotor meets the following criteria, proceed to step  10 .
    • The rotor is within specifications and is being REUSED.
    • The rotor has NOT been refinished.
    • The rotor does NOT exhibit thickness variation exceeding the maximum allowable level.
  10. Mount a dial indicator, Hub and Wheel Runout Gage, or equivalent, to the steering knuckle and position the indicator button so it contacts the brake rotor friction surface at a 90 degree angle, approximately 0.5" (13 mm) from the outer edge of the rotor.
  11. Measure and record the assembled LRO of the brake rotor. Rotate the rotor until the lowest reading is displayed on the indicator dial, then set the dial to zero. Rotate the rotor until the highest reading is displayed on the dial. Mark the location of the high spot relative to the nearest wheel stud, or studs. Measure and record the amount of LRO.
  12. Compare the brake rotor assembled LRO to the following specification. See BRAKE SPECIFICATIONS  .
  13. If the brake rotor assembled LRO is within specifications, proceed to step  18 . If the brake rotor assembled LRO exceeds the specification, refinish the rotor to ensure true parallelism, see BRAKE ROTOR REFINISHING  .
  14. Mount a dial indicator, Hub and Wheel Runout Gage, or equivalent, to the steering knuckle and position the indicator button so it contacts the brake rotor friction surface at a 90 degree angle, approximately 0.5" (13 mm) from the outer edge of the rotor.
  15. Measure and record the assembled LRO of the brake rotor. Rotate the rotor until the lowest reading is displayed on the indicator dial, then set the dial to zero. Rotate the rotor until the highest reading is displayed on the dial. Mark the location of the high spot relative to the nearest wheel stud, or studs. Measure and record the amount of LRO.
  16. Compare the brake rotor assembled LRO to the following specification. See BRAKE SPECIFICATIONS  .
  17. If the brake rotor assembled LRO measurement exceeds the specification, bring the LRO to within specifications. See BRAKE ROTOR ASSEMBLED LATERAL RUNOUT (LRO) CORRECTION  .
  18. If the brake rotor assembled LRO measurement is within specification, install the brake caliper and depress the brake pedal several times to secure the rotor in place before removing the Conical Brake Rotor Washers and the lug nuts.
scientia non olet · About LEMON Manuals