Most often, it is the front rotors that cause the majority of the shaking in most vehicles, especially those that are front-wheel drive. If you are mechanically inclined, replacing brake pads and rotors are one of the easier kinds of repairs that can be performed on a vehicle, and parts are readily available at your local dealership, or parts store, such as NAPA, or AutoZone. If you are experience vehicle shaking due to braking, and need rotors replaced, it is best to start with the front axle, as these are generally going to be the ones causing the shaking or vibration, assuming the age of all the brakes are the same.