So how do disc brakes work?
The main components of a disc brake are:
- The brake pads
- The caliper, which contains a piston
- The rotor, which is mounted to the hub
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The disc brake is a lot like the brakes on a bicycle. Bicycle brakes have a caliper, which squeezes the brake pads against the wheel. In a disc brake, the brake pads squeeze the rotor instead of the wheel, and the force is transmitted hydraulically instead of through a cable. Friction between the pads and the disc slows the disc down.
A moving car has a certain amount of kinetic energy, and the brakes have to remove this energy from the car in order to stop it. How do the brakes do this? Each time you stop your car, your brakes convert the kinetic energy to heat generated by the friction between the pads and the disc. Most car disc brakes are vented.
Vented disc brakes have a set of vanes, between the two sides of the disc, that pumps air through the disc to provide cooling.
Brakes are in use more often when driving around town than on a motorway journey, not forgetting that you may need to use your brakes to stop your vehicle quickly in an emergency. So maintaining an effective vehicle braking system is a top priority for every motorist.
Regular brake checks are an important part of any vehicle preventative maintenance plan. Brake checks can identify a problem before it begins to impact your braking efficiency, thus providing an opportunity to restore the effectiveness of your vehicle's braking system to its intended operating performance.
The effects of a sudden brake failure can be devastating and in the event of an accident attributed to faulty brakes, the consequences of not maintaining an effective braking system could result in prosecution.
Your vehicle will fail its MOT test - if braking efficiency is below specification.
The performance of your vehicle's braking system is tested on a rolling road to measure the amount of braking force generated while operating the hand and foot brake. The braking force generated is then recorded and compared to the manufacturer's specified tolerance level.