Rotor Servicing: Parallelism
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1990 Pontiac Bonneville, 1990 Oldsmobile Ninety-Eight, 1990 Oldsmobile Eighty-Eight, 1990 Cadillac Fleetwood, and 1990 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Check thickness of rotor at 4 or more points around edge of rotor. Make all measurements the same distance from edge. If thickness varies more than specified, refinish or replace rotor.