Brakes are located at each wheel to slow or stop the vehicle.
Brake pads apply pressure to the brake rotors to slow or stop the vehicle. The brake rotor (or disc) is comparable to the rim of a bicycle tire. As the brakes are applied, brake pads come into contact with the brake rotor to slow the vehicle down. As with a bicycle, the harder the brakes are applied, the quicker the vehicle stops.
Brake pad material wears out over time. Brake pads should be periodically inspected for wear, which is highly variable depending on vehicle weight and driver habits. Brake pads must be replaced before the friction material is worn away completely. If it isn't, metal-to-metal contact will occur between the brake rotor and the worn-out brake pad. If metal-to-metal contact occurs, the brake rotor will be damaged, and it will need to be resurfaced or replaced.
The brake rotor is attached to the wheel, which must be removed to gain access to the brake rotor. The brake caliper must then be removed. In some cases, the wheel bearings may also need to be removed. To maintain optimum brake-operating efficiency, replace brake rotors as a set.