How does Anti-lock Braking System work?

Anti-lock Braking System (ABS)

Seen in virtually all except the cheap cars, Anti-lock Braking System (ABS) is a basic anti-lock technique which allows drivers the ability to steer away from danger even during hard braking by avoiding the locking up of wheels.  An ABS is a basic safety system which enables the driver to stop a vehicle quickly and effectively on slippery roads without losing control or traction on the surface of roads.  Anti lock brakes avoid the wheels from ceasing rotation or locking up and thus prevent skidding.

anti lock braking system

The present day advancement of the ABS has now led to it getting merged with Electronic Brakeforce Distribution (EBD), a technology that may vary the quantity of braking force used on each individual wheel.  Let’s see how the anti-lock brakes work and protect the car from skidding.

Four major components to the ABS System


Each brake’s brake line operated by the ABS incorporates a valve. On a few systems, the valve is seen in three positions:
• In first position, the valve stays open; pressure through the master cylinder gets transferred right through towards the brake.
• In second position, the valve obstructs the line, separating that brake from master cylinder. This stops the pressure from increasing further in case the driver pushes the brake pedal with greater force.
• In third position, the valve releases a portion of the pressure exerted on the brake.

Speed Sensors

The ABS requires some way of comprehending when exactly a wheel is going to lock up.  Speed sensors that are positioned at each wheel, or sometimes in the differential offer this data.


This component is actually a computer within the car. It keeps a watch on the speed sensors as well as controls the valves.


As the valve has the ability to release pressure on the brakes, there needs to be some method to set that pressure again. It is exactly the role the pump plays; whenever a valve decreases the pressure in a line, the pressure backup is given by the pump.

How does ABS work?

Controller looks for decelerations within the wheel which are unusual.  Read more »