911 Carrera 4 Cabriolet F6-3.6L SOHC (1998)
7. Check runout of wheel hub as follows:
Measure once outside (arrow) and once inside wheel stud area of hub face.
To fit the dial gauge, use either a universal dial gauge holder, e.g. by SNAP-ON (Part No. PMF 137), or a modified (extended) dial gauge holder
VW 387.
NOTE:Make sure the brake hoses and brake pipes are not damaged when the brake caliper is removed and installed.
8. Excessive lateral runout of wheel hub:
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Replace wheel hub.
Lateral runout of wheel hub o.k.:
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Clean leveling and centering surfaces of brake disc and wheel hub. Then apply a thin coat of Optimoly TA to centering surface of wheel hub.
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Fit brake disc to wheel hub in a different position offset radially with regard to wheel hub.
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Repeat measurement with adapter plate fitted (Special Tool 9510/1).
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If the lateral runout is still in excess of 0.09 mm, the brake disc must be replaced.
NOTE:If the brake disc runout has been reduced by offsetting the brake disc radially with regard to the wheel hub, one 6 mm countersunk head
screw may be omitted if two 6 mm screws had been fitted.
Thickness Variation
Measure the brake disc thickness variation within the braking surface at approx. 8 points by using the micrometer. Thickness tolerance of the brake disk
max. 0.02 mm (new condition max. 0.01 mm).
Wear Assesment
Checking Brake Discs (Wear Assessment)
Includes:
1. Visual inspection for cracks and crack assessment.
2. Checking brake discs for minimum thickness.
General