Checking the lateral runout of the wheel hub | HELLA

As part of troubleshooting on the brake disc system, as well as before fitting new brake discs, the axial runout of the wheel hub should also be checked according to the specifications of the vehicle manufacturer.

To test the lateral runout of the wheel hub, we recommend the following procedure.

Prepare the wheel hub:

• Check surface for corrosion and damage
• Check thread for damage
• Remove contamination and traces of corrosion
• The contact face of the wheel hub must be undamaged, rust-free, clean and bright

Test:

1. Fasten the dial gage with holder to the suspension strut
2. Align the dial gage at the outer edge of the wheel hub
3. Turn the wheel hub slowly and at a constant speed in the direction of travel
4. Read off the measured values

Measured over several wheel revolutions, deviations should not exceed 0.03mm. If the deviations are greater, the hub should be replaced.

• This test should be carried out before mounting the new brake discs
• Unevenness on the contact face of the wheel hub can lead to warping of the brake disc and therefore axial runout.
• Any hub runout present will cause twice the disc runout at the outer edge of the brake disc

Please observe the specifications in the maintenance and repair notes provided by the respective vehicle manufacturer.