Tools Required
J 8001 Dial Indicator
set, or equivalent
- With the tire and wheel assemblies removed and the brake rotors
retained by wheel lug nuts, clean the braking (friction) surfaces of the brake
rotor with denatured alcohol or an equivalent approved brake cleaner.
- Inspect the braking 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; heavy surface
rust and/or pitting must be removed by refinishing the rotor. |
• | Cracks and/or heat spots |
• | Excessive blueing discoloration |
- If the braking surfaces of the brake rotor exhibits one or more
of the braking surface conditions, the rotor requires refinishing or replacement.
- Using a micrometer calibrated
in ten-thousands of an inch, measure and record the thickness variation of
the brake rotor at four or more points, around the rotor.
Ensure that the measurements are only taken within the brake pad lining
contact area and that the micrometer is positioned the same distance from
the outside edge of the rotor for each measurement.
- Compare the thickness variation recorded to the following specification:
Specification
Brake rotor maximum allowable thickness variation 0.025 mm (0.001 in).
- If the brake rotor thickness variation exceeds the specification,
the rotor requires refinishing or replacement.
- Using the micrometer, measure and record any grooves present on
the rotor braking surface.
- Compare the groove (scoring) depth recorded to the following specification:
Specification
Brake rotor maximum allowable scoring 1.50 mm (0.059 in).
- If the brake rotor scoring depth exceeds the specification, or
if an excessive amount of scoring is present, the rotor requires refinishing
or replacement.
- Mount a dial indicator, J 8001
or equivalent, and position
the indicator button so it contacts the brake rotor at a 90 degree
angle, approximately 13 mm (0.5 in) from the rotor's outer
edge.
- Measure and record the lateral runout of the brake rotor.
11.1. | Rotate the rotor until the lowest reading is displayed on the
indicator dial, then zero the dial. |
11.2. | Rotate the rotor until the highest reading is displayed on the
dial. |
11.3. | Measure and record the amount of sealed wheel bearing play, then
subtract the bearing play from the lateral runout recorded to obtain the true
amount of lateral runout. |
- Compare the lateral runout of the brake rotor to the following
specification:
Specification
Brake rotor maximum allowable lateral runout 0.051 mm (0.002 in).
- If the brake rotor lateral runout exceeds the specification, the
rotor requires refinishing or replacement.