G 1500 1/2 Ton Van V6-4.3L VIN W (1997)
Brake Rotor/Disc: Testing and Inspection
Rotor Tolerance and Surface Finish
During the manufacture of the brake rotor, tolerances of the braking surfaces for flatness, parallelism, and lateral runout are closely held. The
maintenance of close tolerances on the shape of the braking surfaces is necessary to prevent brake roughness or pulsation. In addition to these tolerances,
the surface finish must be held to a specified range of 60 Ra roughness or less. The control of the braking surface finish is necessary to avoid problems
of hard pedal apply, excessive brake fade, pulls and erratic performance. In addition, control of the surface finish can improve lining life. Light scoring
of the rotor surfaces not exceeding 1.5 mm (0.06 inch) in depth is normal and not detrimental to brake operation.
