A major component of your car's braking system, the brake disc sits on the wheel hub and slows the vehicle down when the brakes are applied through the use of friction. Your vehicle's brake pads 'grab' onto either side of the brake discs through the application of a hydraulic piston. This reduces the speed of the vehicle and allows it to come to a safe stop.
Although made of high tensile steel, brake discs for any make and model of car can become worn or pitted over time, and will ventually need replacing. Worn brake discs can produce inefficient braking results, so it is important to check your discs regularly and replace with high quality brake discs only.