Sierra 1500 2WD V6-4.3L (2008)
3. Using a micrometer calibrated in thousanths-of-a-millimeter, or ten-thousanths-of-an-inch, measure and record the thickness of the brake rotor at
four or more points, evenly spaced around the rotor.
Ensure that the measurements are only taken within the friction surfaces and that the micrometer is positioned the same distance from the outer
edge of the rotor, about 13 mm (1/2 in), for each measurement.
4. Calculate the difference between the highest and lowest thickness measurement recorded to obtain the amount of thickness variation.
5. Compare the thickness variation measurement to the following specifications:
Brake rotor maximum allowable thickness variation: 0.025 mm (0.001 in)
Brake rotor maximum allowable thickness variation: 0.009 mm (0.0004 in)
Important: Whenever a brake rotor is refinished or replaced, the assembled lateral runout (LRO) of the rotor must be measured to
ensure optimum performance of the disc brakes.
6. If the brake rotor thickness variation measurement exceeds the specification, the rotor requires refinishing or replacement.
