Tools Required
J 8001 Dial Indicator, or
equivalent
- With the tire and wheel assemblies removed and the brake rotors retained
by wheel lug nuts, clean the braking 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 4 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
0.050 mm (0.002 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
0.050 mm (0.002 in).
- If the brake rotor lateral runout exceeds the specification, the rotor
requires refinishing or replacement.