Brake Rotor Thickness Measurement

Special Tools 

CH-230-A  Disc Gauge

Equivalent regional tools:Special Tools 

1. If the inboard friction surface of the brake rotor is not accessible, remove the brake pads. Refer to Front Disc Brake Pads Replacement  and/or Rear Disc Brake Pads Replacement , if equipped.
   WARNING: Refer to Brake Dust Warning .
   Fig 1: Locating Disc Gauge

   Courtesy of GENERAL MOTORS COMPANY
2. Clean the friction surfaces of the brake rotor with denatured alcohol or an equivalent approved brake cleaner.
3. Install the CH-230-A  gauge for lateral runout measurement.
   NOTE: Ensure the measurements are only taken within the friction surfaces.
   1. Measure and record the thickness of the brake rotor at 4 or more points from the brake rotor inside to outside.
   2. Compare the lowest thickness measurement to the disc brake component specifications. Refer to Disc Brake Component Specifications .
4. If the lowest thickness measurement of the brake rotor is above the minimum allowable thickness after refinishing specification, the rotor may be able to be refinished, depending upon surface and wear conditions which may be present.
5. If the lowest thickness measurement of the brake rotor is at or below the minimum allowable thickness after refinishing specification, the rotor may not be refinished.
6. If the lowest thickness measurement of the brake rotor is at or below the discard thickness specification, the rotor requires replacement. Refer to Front Brake Rotor Replacement (15 inch Brake System J67 and J93) , Front Brake Rotor Replacement (16 inch Brake System J60)  and/or Rear Brake Rotor Replacement .