Car shaking when braking?

Answer 1

Usually this is a sign of warped brake rotors. In order to tell if they are warped at the front, you should be able to feel a pulsing sensation through the steering wheel/brake pedal whilst braking lightly at ~100kmh (60mph). If they are warped at the rear (not usually the case but not unheard of), you may feel a pulsing feeling through the brake pedal and a slight vibration through the seat.

In order to remedy this, go and talk to your automotive repair shop who should be able to assist you further and find out what the actual cause may be. They may be able to 'machine' the brake rotors (if they are At Fault) so that they are no longer warped. If this is not possible, they may recommend replacement brake rotors. In both cases, it is recommended to replace your brake pads so that they mate perfectly to the rotor surface.

Answer 2

You have warped rotors. Replacement or machining of rotors is necessary to correct that problem.