Q&A

 Master

Typically, this symptom is caused by front brake rotors that are warped or have some form of run-out. Most likely, the rotors will have to be machined or replaced if under legal limits.

 Technician

Shaking when braking is almost always caused by disc brake rotors that are thicker in some spots than they are in other spots. As the brake pads are applied and squeeze the rotor they try to follow the irregularities. As they do, you will feel a pulsation in the brake pedal or in the vehicle itself.

This condition may be temporarily corrected by "Machining" or replacing the rotor, but if the condition returns, it may be caused by warped hub flange. A warped hub flange will causes the rotor to wobble when it rotates. This wobbling will cause the surface of the rotor to hit the brake pads in only one spot on one side of the rotor and on a different spot on the other side of the rotor. These spots will wear causing the rotor to be thinner in some spots than others and again making the brakes pulsate.

To correct this condition we use a process known as rotor matching. Rotor matching requires us to install the rotor on vehicle and then machine it's surface in place. Any warping of the hub flange will be then compensated for by the machining process.

There are several vehicle manufactures that recommend this process to permanently correct this problem. It is a little extra work, but it is well worth the effort.