How Brakes Work
The brake pedal is connected to the master cylinder located within the engine compartment. The cylinder is filled with brake fluid. When you push down the brake pedal, hydraulic pressure is created in the master cylinder, brake fluid is pressurised along a series of brake pipes and hoses to the hydraulically activated pistons in each wheel's hub assembly that force the friction material on your pads or shoes on to rotating parts, and that's what stops your car. There are two types of brake assembly commonly available – disc brakes and drum brakes. In addition, the majority of modern cars are fitted with ABS as standard.
A disc brake system consists of a brake disc, a brake calliper and brake pads. When the brake pedal is applied, pressurised hydraulic fluid squeezes the brake pad friction material against the surface of the rotating brake disc. The result of this contact produces friction which enables the vehicle to slow down or stop.
A drum brake system consists of hydraulic wheel cylinders, brake shoes and a brake drum. When the brake pedal is applied the two curved brake shoes, which have a friction material lining, are forced by hydraulic wheel cylinders against the inner surface of a rotating brake drum. The result of this contact produces friction which enables the vehicle to slow down or stop.
ABS and Parking Brakes
Anti-lock braking systems (ABS) work by limiting, applying and releasing the pressure to any wheel that decelerates too quickly. This allows maximum stopping force to be applied without the brakes locking-up and the car skidding. Your vehicle’s ABS tests itself each time the ignition is turned on. If a defect is detected for whatever reason, the ABS turns itself off and the normal braking system is used on its own. The ABS warning light will inform the driver of a defect in the system.
The parking or hand brake is a lever mechanism that is applied to hold a vehicle in a parked position. It activates braking components at the rear of the vehicle's braking system.