Buick Regal: Brake Rotor Thickness Measurement

Special Tools

CH-230 - A Disc Gauge

Equivalent regional tools: Special Tools

WARNING: Refer to Brake Dust Warning.

1. If the inboard friction surface of the brake rotor is not accessible, reposition and support the caliper with the brake pads. Refer to Front Disc Brake Pads Replacement (J60)Front Disc Brake Pads Replacement (JQ5)Front Disc Brake Pads Replacement (J17), and/or Rear Disc Brake Pads Replacement (GNC)Rear Disc Brake Pads Replacement (GNQ), if equipped.

2. Clean the friction surfaces of the brake rotor with denatured alcohol, or an equivalent approved brake cleaner.

3.

NOTE: Ensure the measurements are only taken within the friction surfaces.

Install the CH-230 - A Disc Gauge for brake rotor thickness measurement.

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 at or below the discard thickness specification, the rotor requires replacement. Refer to Front Brake Rotor Replacement (JQ5)Front Brake Rotor Replacement (J17, J60), and/or Rear Brake Rotor Replacement.

BRAKE ROTOR THICKNESS VARIATION MEASUREMENT

WARNING: Brake Dust Warning.

Removal Procedure

1. Remove the tire and wheel assembly.

2. Remove the disc brake pads of the brake rotor which is to be measured:

• Front Disc Brake Pad - Remove.
• Rear Disc Brake Pad - Remove.

Measurement Procedure

1.

NOTE: Range of the micrometer: 0 - 50 mm (0 - 1.969 in)

Measure the thickness of the brake rotor, using a micrometer (1):

• Measure approximately 5 mm (0.197 in) from the outer edge of the rotor.
• Measure on 8 evenly spread points at the same circumference.

2. Note the variation of the thickness.

3. Compare the measures with the maximum allowable thickness variation.

Installation Procedure

1. Install the disc brake pads.

• Front Disc Brake Pad - Install
• Rear Disc Brake Pad - Install

2. Install the tire and wheel assembly.

BRAKE ROTOR SURFACE AND WEAR INSPECTION

WARNING: Refer to Brake Dust Warning.

1. If the inboard friction surface of the brake rotor is not accessible, reposition and support the caliper with the brake pads. Refer to Front Disc Brake Pads Replacement (J60)Front Disc Brake Pads Replacement (JQ5)Front Disc Brake Pads Replacement (J17), or/and Rear Disc Brake Pads Replacement (GNC)Rear Disc Brake Pads Replacement (GNQ).

2. Clean the friction surfaces of the brake rotor with denatured alcohol, or an equivalent approved brake cleaner.

3. Inspect the friction surfaces of the brake rotor for the following Braking Surface Conditions:

• Heavy rust and/or pitting.
• Light surface rust can be removed with an abrasive disc.
• Cracks and/or heat spots.
• Excessive blueing discoloration.

4. If the friction surfaces of the brake rotor exhibit one or more of the braking surface conditions, the rotor requires replacement. Refer to Front Brake Rotor Replacement (JQ5)Front Brake Rotor Replacement (J17, J60), or Rear Brake Rotor Replacement.

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