GM Service Manual Online
For 1990-2009 cars only

In the manufacturing of brake rotors, tolerances of the braking surfaces for the following conditions are held very closely:

    •  The Flatness
    • The thickness variation
    •  The lateral runout

The maintenance of close tolerances on the shape of braking surfaces is necessary in order to prevent roughness in braking performance.

In addition to these tolerances, the surface's finish must be held to specified range.

The control of the braking surface finish is necessary to avoid the following conditions:

    • Pulls
    • Erratic performance
    • Reduced lining life

Light scoring of the rotor surfaces not exceeding specifications (which may result from normal use) will not affect brake operation.

The maximum scoring of the rotor surface is 0.38 mm (0.015 in).