A disc brake is a type of brake that uses the calipers to squeeze pairs of pads against a disc or rotor to create friction. Brake Discs are most commonly made of cast iron or steel; however some very high-end cars use a carbon ceramic rotor. Discs are mounted on the hub and rotates together with the wheel. During braking, kinetic energy of the vehicle converts into heat due to friction between pads and the disc. To better dissipate the heat, most vehicles have ventilated discs on the front wheels.
As a result of the friction, rotors wear out. On an average car, disc brakes normally last for 50,000-65,000 Kilometers. Brakes are vital for safe driving and any problems with the braking system should be dealt immediately. Some of the common indicators for brake system issues are noise while braking, vibration, greater braking distance etc.