Cutlass V6-191 3.1L VIN M SFI (1998)
Brake Rotor/Disc: Testing and Inspection
Brake Rotor Lateral Runout Check
Check the lateral runout with the wheels still installed on the vehicle. This gives a much more accurate reading of the Total Indicated Runout (T.I.R.)
under real braking conditions. If equipment is not available to perform the check with the wheels installed, obtain the next best reading with the wheels
removed but with the caliper still installed.
1. Clean the rotor surface.
IMPORTANT: If the wheel must be removed, re-install the wheel nuts to retain the rotor. Tighten the wheel nuts to the correct tightening
specification following the wheel nut tightening sequence.
2. Fasten a dial indicator to the steering knuckle so that the indicator button contacts the rotor surface about 13 mm (0.5 in) from the outer edge.
3. Set the dial indicator to zero.
NOTICE: Whenever the brake rotor has been separated from the wheel bearing flange, clean any rust or foreign material from the mating surface
of the wheel bearing flange and rotor. Failure to do this may result in increased lateral runout of the rotor and brake pulsation.
4. Turn the wheel one complete revolution and observe the runout indicated on the dial. The T.I.R. must not exceed 0.08 mm (0.003 in).
In some cases, excessive lateral runout of the rotor may be improved by indexing the rotor on the hub, one or two bolt positions from the original
position. If the lateral runout cannot be corrected by indexing the rotor, inspect the hub and bearing assembly for excessive lateral runout or
looseness. If the hub and bearing assembly lateral runout exceeds 0.040 mm (0.0015 in), replace the hub and bearing assembly. If lateral runout is
not within specifications, replace the rotor as necessary.
