PRE-RELEASE
Checking for lateral run-out and variation in thickness, front wheels
| Checking for lateral run-out and variation in thickness, front wheels |
| 1. |
Raise the car and remove the front wheels.
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| 2. |
Start by control measuring on one side.
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| 3. |
Press in the piston
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Level 1 and 2:
Press in the brake pad by prising with a screwdriver.
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Level 3:
Prise between the brake disc and the brake caliper using a screwdriver.
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| 4. |
Remove the brake caliper retaining bolts and lift of the caliper.
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| 5. |
Suspend the caliper with cable ties.
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| 6. |
Fit the five wheel bolts with one washer, part no. 80 73 124, on each.
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| 7. |
Fit
89 96 639 Gauge, brake disc
to the upper mounting lug for the brake caliper with an M10 bolt and nut. Fit a
78 40 622 Dial gauge
on either side.
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| 8. |
Rotate the brake disc while observing the outboard dial gauge. Zero both gauges when the negative reading obtained on the outboard one is at maximum.
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| 9. |
Rotate the disc and read the gauges. Note the runout (A) and variation in thickness (B).
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| 10. |
Check that the readings are within the tolerance limits, see
Brake discs
.
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| 11. |
Remove the dial gauges, brake disc measuring tool and wheel studs with washers.
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| 12. |
If runout and thickness variation exceeds specified tolerances, the discs must be machined or replaced. see
Brake disc, front
.
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| 13. |
Fit the brake caliper. Secure the bolts with
74 96 268 Thread locking adhesive
.
Tightening torque: 210 Nm +30° (155 lbf ft +30°) 
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| 14. |
Fit the wheel
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| 15. |
Repeat this method of measurement on the other brake disc.
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| 16. |
Lower the car and depress the brake pedal to press out the brake pads.
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