About Brake Systems
A car's braking system is one of its most vital safety and performance components. Brakes keep drivers safe by allowing them to slow the...
A car's braking system is one of its most vital safety and performance components. Brakes keep drivers safe by allowing them to slow the speed of a vehicle or stop quickly in an emergency. A braking system has several different components that give drivers control and make cars safe to drive.
Components
A vehicle's brake system is composed of several individual pieces of equipment. These include the brakes themselves, with one brake mounted inside each wheel. The master cylinder, located under the hood, controls the entire brake system. Brake lines connect the master cylinder to each of the brakes. Brake fluid fills the brake lines. And no brake system would be complete without the pedal inside the car for the driver to operate.
Operation
When a driver depresses the brake pedal, a series of reactions occur quickly. The pressure on the pedal is turned into hydraulic pressure in the master cylinder. This pressure forces brake fluid through the lines, which causes the brakes to activate. Different brakes work in different ways, but in each case, the brake causes friction by forcing a pad into contact with a rotating element linked to the vehicle's axle, thus slowing the car.
Types
Two major types of automobile brakes are used on most cars today. The first are disc brakes, which use a pair of calipers with pads to pinch a spinning metal disc and slow the car. Drum brakes use shoes instead of pads. Brake shoes expand outward inside a rotating metal drum, pressing against the inside of the drum and creating the friction to slow the car.
Today most vehicles use disc brakes in the front wheels, which generate most of the stopping force. Some older cars and modern trucks use drum brakes in the rear, while more and more automakers offer disc brakes in all four wheels for newer cars.
Maintenance
A vehicle's brake system requires regular maintenance as part of a standard vehicle service schedule. Because the wear on the brake system depends on driving conditions and the materials used in its construction, there is no set deadline for replacing components. However, most vehicles will go through several sets of brake pads and shoes in a lifetime. Brake lines may rust over time, requiring replacement before they leak brake fluid and reduce the effectiveness of the brake system.
Variations
Brake system components vary in other ways. Brake pads are made of many different materials. For example, ceramic brake pads are quiet and smooth but wear down quickly, while semimetallic pads last longer but erode the rotor and may create noise or vibration during braking.
Hybrid-electric cars use an adaptive braking system to generate electricity from the friction caused by braking, and that power is stored for the car's future use.
Federal law also requires all cars to contain an emergency brake, which relies on solid wires rather than hydraulic brake lines to stop a car in an emergency or in case of brake failure.
