Anti-lock Brake Systems (ABS)

The ABS is a four-wheel system that prevents wheel lock-up by automatically modulating the brake pressure during an emergency stop. By preventing the wheels from locking, it enables the driver to maintain steering control and to stop in the shortest possible distance under most conditions.During normal braking, the ABS and non-ABS brake pedal feel will be the same. During ABS operation, a pulsation can be felt in the brake pedal, accompanied by a fall and then rise in brake pedal height and a clicking sound.
more detail

How Brakes Work

Brakes operate by converting the kinetic energy (motion) of an automobile into heat energy. How effectively this is achieved depends on the type of braking system. There are two main types of brakes that have been used in cars. These are disc brakes and drum brakes. Disc brakes operate in a similiar fashion to that of a bicycle. It involves pushing a block against a spinning wheel. This contact causes friction, which changes kinetic energy into heat energy. Automobiles use two of these blocks, one on each side of the wheel, which helps keep the wheel more stable. When the brake pedal is pushed, the blocks (often called brake shoes) push up against the wheel disc. The actual wheel is attached to this disk and the two spin together. Therefore, when the disc is slowed, the wheel also slows.
more detail