Do you brake and feel a vibration in the brake pedal? Explanations.
The most likely reason that you feel vibrations through the brake pedal is because a rotor — the rotating disc that the brake pads are pressed against — is unevenly worn, or what some call “warped.” (It’s unlikely that a rotor could truly warp from normal use as opposed to a manufacturing defect, but thinner and thicker sections — uneven wear — have the same effect.)
Brake vibration, or what some refer to as a shudder or pulsation, often is the result of parts of the rotor being thinner than others instead of uniform all around. As the brakes are applied, the pads will be pressed against high and low spots that the driver feels through the pedal. Rust and dirt also can build up on a rotor and cause minor pulsations.
A rotor’s thickness needs to vary by only a few thousandths of an inch for the driver to feel it. In more serious cases, the whole car can shake when the driver hits the brakes.
Some vehicles still have rear drum brakes in which brake shoes (essentially curved brake pads) are pressed outward against the walls of the drum. The drums also can wear unevenly and cause vibrations that might be solved by machining the braking surface.