ROTOR RUNOUT
On-vehicle rotor runout is the combination of the
individual runout of the hub face and the runout of
the rotor. (The hub and rotor runouts are separable).
To measure rotor runout on the vehicle, first remove
the tire and wheel assembly. Reinstall the wheel
mounting nuts on the studs, tightening the rotor to
the hub. Mount the Dial Indicator, Special Tool
C-3339, with Mounting Adaptor, Special Tool SP-
1910 on the knuckle steering arm. The dial indicator
plunger should contact braking surface of rotor
approximately one inch (25 mm) from edge of rotor
(Fig. 50). Check lateral runout on both sides of the
rotor, marking the low and high spots on both.
Runout limits can be found in the specification table
in this section. (Refer to 5 - BRAKES/HYDRAULIC/
MECHANICAL/ROTOR - SPECIFICATIONS)
If runout is in excess of the specification, check the
lateral runout of the hub face. Before removing the
rotor from the hub, place a chalk mark across both
the rotor and the one wheel stud closest to where the
high runout measurement was taken. This way, the
original mounting spot of the rotor on the hub is
indexed (Fig. 51).
Remove the brake rotor from the hub. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/ROTOR -
REMOVAL).
NOTE: Clean the hub face surface before checking
runout. This provides a clean surface to get an
accurate indicator reading.
Fig. 49 Checking Rotor Thickness
1 - CALIPER
Fig. 50 Checking Rotor Runout
1 - SPECIAL TOOL SP-1910
2 - ONE INCH FROM EDGE
3 - DISC SURFACE
4 - SPECIAL TOOL C-3339
Fig. 51 Marked Rotor And Wheel Stud
1 - CHALK MARK
5 - 32 BRAKES - BASE ZB
ROTOR (Continued)
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