Car Brakes Information

A brake is an object or device used to apply force to a moving object in order to reduce its motion and bring it to a halt. Brakes used on vehicles commonly bring a moving surface into contact with a stationary surface to generate friction, which slows and eventually stops the vehicle. The brakes used on cars at the beginning of the 21st century are usually either disc or drum brakes, with some manufacturers choosing a combination of the two.

History

State University reports that brakes were initially invented for use with steel-rimmed wheels of horse drawn carriages and steam locomotives with a wooden block often applied to the wheel to force the vehicle to a stop. The introduction of rubber tires by the Michelin brothers in 1895 brought about research into a more efficient way of braking vehicles as the previous versions were unworkable with rubber tires. In 1899 the Daimler car manufacturer developed a system of drum braking called servo assistance where a cable attached to the chassis of the car would tighten around the drum to reduce resistance on the brake pedal. The servo system is still in operation today where the drum brake is used.

Drum

The drum brake was the first new method of braking introduced in the late 19th century with components such as the brake shoes housed in a drum that spun with the wheel. The automotive website Edmunds explains that when the brake pedal of a motor car is depressed the brake shoes are forced against the drum slowing the wheel and the car.

Disc

According to Edmunds, disc brakes were introduced in the 1970s as a way of increasing the efficiency of braking on cars used for racing, which over the subsequent years has trickled down to cars used for everyday purposes. A small caliper holds two brake pads, one on either side of a rotor which is attached to the wheel. When the brake pedal is depressed, the caliper clamps the two brake pads to the rotor creating friction and heat that slow the wheel.

Problems

The drum braking system carries a number of problems, the main being a reduction in braking ability when the hardware contained in the drum becomes too hot with friction. According to Edmunds, reduced braking ability was a problem in large vehicles carrying heavy loads when the drum braking system could not cool itself. Disc brakes, on the other hand, are not enclosed and therefore are cooled by outside air flowing over the discs as the car moves. As the cost of producing disc brakes is higher and forces up the retail cost of building a car, Edmunds reports, many manufacturers are using disc brakes for the front wheels of a car and cheaper drum brakes for the rear where less force is needed to slow the vehicle.

ABS

According to the National Highway Traffic Safety Administration, the antilock braking system is a common feature on cars manufactured in the early part of the 21st century. This advance in car braking reduces the chances of brakes locking the car's wheels in place and not allowing the driver to steer away from danger. Before the advent of antilock braking, to avoid skidding and locking brakes a driver would pump the brake manually but the antilock brakes now do this automatically, allowing the driver to steer as the car brakes.