Brakes - Vibration

90hyundai02 Subject


CHECKING BRAKE DISC AND HUB RUN-OUT
Group CHASSIS


Number 005


Date July, 1990


Model Sonata
Brake vibration can be caused by a combination of excessive hub and brake disc run-out. The following procedure should be performed to service vehicles experiencing brake vibration.


SERVICE PROCEDURE



1. Remove the front wheel and tire assembly. Remove the front brake caliper assembly and suspend it with a wire. Remove the brake disc.

2. Clean the surface of the hub with brake cleaner and then check the run-out. The hub run-out should be measured as close to the outer edge as possible on the face of the hub and should not exceed 0.05 mm. Replace the hub if necessary following procedures in the Sonata Shop Manual.



3. When installing a new hub, check run-out to confirm it is within specifications.

4. Machine the brake disc, but maintain the minimum thickness marked on the disc.

5. Reinstall the machined brake disc or, if necessary, a new disc using four nuts to hold the disc temporarily against the hub. Snug the nuts up to the disc in an X-pattern.
NOTE: If using a new brake disc, do not machine the new disc.

6. Measure total run-out at the outer edge of the rotor face. Verify that total run-out is within the specification of 0.1 mm. Check the run-out on both the front and back surface of the disc. If the total run-out still exceeds 0.1 mm, re-index the disc 180 degrees from its original position on the hub and recheck.
7. Reinstall the caliper and remove the nuts holding the disc onto the hub. Reinstall the wheel and tire assembly, torquing the lug nuts to 65-80 lb.ft.

8. Repeat steps 1 through 7 for the other side.

9. Test drive vehicle to verify that brake vibration has been eliminated.


RUN-OUT SPECIFICATIONS
Hub run-out: 0.05 mm (0.002 in.) Maximum
Total run-out: 0.10 mm (0.004 in.) Maximum (with disc mounted on hub)



WARRANTY INFORMATION
Run-out measurement includes clean hub, check hub run-out, and check total run-out on inside and outside of disc.