There are a number of components in the braking system which can cause brake failure:
Drum brake systems are commonly used on the rear of a vehicle. The hydraulic system is initiated by pressing the brake pedal which causes two shoes inside a drum to move outwards making contact with the inner surface of the drum, causing resisting friction. The drum is connected to the wheel, so in this instance, results in friction being simulated from the drum to the wheel and causes the vehicle to stop.
Disc brakes may be on the front wheels or, more frequently, on all four wheels. The hydraulic system is initiated by pressing the brake pedal which causes two pistons to push two pads onto either side of a disc in a clamping motion. Brake discs are fixed to the wheels, therefore, when the pads clamp onto the discs, friction occurs and the wheels slow down bringing the vehicle to a stop.
ABS (Anti-Locking Brake System)
ABS works on the principle that locked or skidding wheels will not created enough friction to stop the vehicle safety. So, ABS is there to assist the driver when elements out of their control prevent a safe stop. There are four main components to the ABS system: these are Speed, Sensor, Controller, Valves and Pumps.
Speed sensors appear on each wheel which relay speed measurements to the controller, which is an on board intelligence computer chip. Depending on the measurements the controller will operate valves in the brake fluid line to either remain:
- Open: allowing normal operation
- Closed: stopping excessive pressure through the fluid to the braking system to prevent brake lock
- Or Narrow: to minimise the pressure through the brake lines again to prevent brake lock
In instances where valves close or narrow, a pump is in place to restore normal fluid pressure back to the lines after the vehicle has stopped safely.