Pedal Pulsation

DISC BRAKES
Causes

Lack Of Parallelism:

- Excessive lateral runout (warpage) or lack of parallelism (rotor thickness variation) .
- Loose or worn front suspension components. Worn components which allow lateral movement of the wheel/hub assembly may produce a pulsating pedal or a shimmy in the front end of the vehicle upon braking.
- Loose or worn wheel bearings

What to Check For

Lack Of Parallelism:

- Measure the rotor with a micrometer and a dial indicator. Resurface or replace the rotor if runout exceeds .004" or if thickness variation exceeds .0005" when measured at several places of equal distance from rotor edge.

NOTE: Excessive lateral runout may be caused by unevenly torqued lug nuts or loose wheel bearings. Check wheel bearings and lug nut torque prior to measuring the rotor.

- Check all front suspension components for worn bushings or looseness and replace if necessary.
- Check front wheel bearings and replace if necessary.