Drum brakes consist of a brake drum attached to the wheel, a wheel cylinder, brake shoes, and brake return springs. Hydraulic pressure from the master cylinder causes the wheel cylinder to press the brake shoes against the brake drum. This creates friction between the shoes and drum to slow or stop your car.
Vehicles also come equipped with a secondary braking system, known as emergency, or parking brakes. Emergency brakes are independent of the service brakes and are not powered by hydraulics. Parking brakes use cables to mechanically apply the brakes (usually the rear brake).
There are a few different types of emergency brakes, which include: a stick lever located between the driver and passenger seats; a pedal located to the left of the floor pedals; or a push button or handle located somewhere near the steering column. Emergency brakes are most often used as a parking brake to help keep a vehicle stationary while parked. And, yes, they are also used in emergency situations, in case the other brake system fails!
Computer-controlled anti-lock braking systems (ABS) is an important safety feature which is equipped on most newer vehicles. When brakes are applied suddenly, ABS prevents the wheels from locking up and the tires from skidding. The system monitors the speed of each wheel and automatically pulses the brake pressure on and off rapidly on any wheels where skidding is detected. This is beneficial for driving on wet and slippery roads. ABS works with the service brakes to decrease stopping distance and increase control and stability of the vehicle during hard braking.