How Do Disc Brakes Work?

The basic way a disc brake system works is toWarping discs reduced their ability to stop the car. So
transfer the kinetic energy of the rotating wheelsother designs were developed. One approach was to
into heat with friction which will stop your vehicle.hollow out with either fins or vanes joining the disc's
The major components of the disc brake systemtwo contact surfaces. This was called a "ventilated"
are:disc design.
First a hydraulic system to transfer fluid from theThe caliper has one or more pistons who press the
movement of the brake pedal into movement of thepads against the disc. Various designs have been
brake pads.used, but today the most common is called a
A rotor or disc, made out typically of a material likesingle-piston floating-caliper which is both
iron, that spins with your wheels.self-centering and self-adjusting. This caliper is able to
A caliper with one or more pistons that move theslide from side so it will move to the center each
brake pads onto the disc.time the brakes are applied. Some newer cars have
And of course the brake pads.two or more pistons, and some exotic cars are
Let's examine the three major components, the disc,offered with four pistons. Additional pistons increase
the caliper and the pads. The disc must withstand athe breaking ability of the car.
great deal of heat as it works to slow down the car.The last major component is the brake pad. Pads are
Early discs were made of solid cast iron. This workeddesigned for high friction, and early brake pads
fine for most cars, but those that went really fast orcontained some amount of asbestos. This presents a
weighed a great deal found that the solid cast irondanger if you find yourself working on an older car,
disc could overheat and warp.usually with drum brakes.