Why do my brakes pulsate?
Brake pulsations are caused by the following:
Aggressive braking. Worn or damaged wheel bearings and hubs.
Stuck or frozen calipers, pins and slides.
Rust and pad material accumulation on rotor surface.
Out of round brake drum or failed drum brake hardware.
Frozen parking brake cable
Worn out brake linings, pads or shoes.
All of these things can cause excessive heat build-up on the rotors or drums resulting in brake pulsations.