A vibration that appears only when you brake is one of the most common complaints workshops hear. It is usually a brake issue, but not always.
Most common causes
- Uneven disc thickness (often called "warped discs"). Uneven pad deposits or wear make the disc thicker in places, and the pedal pulses as it rotates.
- Sticking caliper or slide pins, which keep one pad dragging and overheating the disc.
- Worn suspension or steering joints, which let normal braking forces shake the wheel.
- Loose or unevenly tightened wheel nuts. Wheels should be torqued in the correct pattern.
Where you feel it is a clue
Vibration through the steering wheel usually points to the front brakes or front suspension. A pulsing pedal with a steady wheel often points to the rear discs.
The fix
Discs that are still above minimum thickness can sometimes be resurfaced; otherwise they are replaced, usually with new pads. Calipers are cleaned, lubricated or overhauled as needed. See brake maintenance and suspension.