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How Do ABS Brakes Work

Kulbhushaan Raghuvanshi
In this story we find out about one of the most important car parts, ABS brakes. How they work, and how do they benefit in-car safety is described in the story. Take a look...
All cars today are fitted with ABS brakes and how they work is the first question that comes to mind when you think of the ABS (Anti-Lock Braking System). Automobile technology is daily trying to scale new heights with advancements and deep research. Introduction of ABS was a great revolutionary concept of automobile technology.
An ABS is a car brake system which allows the wheels of your car to stop slowly without skidding and preventing the wheels from locking up. Stopping the car on slippery roads can prove quite dangerous for the driver. It can lead to an unfortunate accident and due to which the car and driver can suffer heavy damages.
This system was introduced in the 1980s' and since then has been a standard equipment is most cars. Since it has been on the road for quite sometime, let's learn something more about them.

How ABS Brake Works

The main answer behind how this technology works is pretty simple. The anti lock braking system is mainly designed for a safe and comfortable ride. A wheel which is skidding has less traction on the road than a wheel which is not skidding.
When a car is driven on wet roads, it is pretty clear that the wheels are going to get very little traction when the brakes are applied. This is because the contact patch of the tire on the wet area suffers lesser friction.
The ABS avoids wheels from locking when braked, letting them rotate at a lower speed, thereby preventing the car from skidding. This results in your car coming to a halt at shorter distance.
In this section we discuss on how does this system work in simple terms. The controller system is an important car part and keeps an eye on the increasing speed of the car all the time. It is looking for different movements in the car wheel which may be sudden and fast. when the brakes are applied the sensors sense a reduction in the wheel speed.
The sensors actuate the brake valves on the slowing wheel, thereby releasing the brakes allowing it to rotate. This effectively prevents locking of the wheel and skidding of the vehicle. Conversely if the sensor detects that a wheel is rotating faster than the other wheels, it actuates the braking system on the faster wheel.
This whole process is continuous and happens repeatedly in cars with ABS. The resulting effect for a driver is that he/she experiences a safer drive wherein his car does not skid and stops and earlier and faster.

ABS Brake System Components

ABS is made of four main components which guarantee the smooth functioning of the system and without these three options the answer to how ABS brake work cannot be completed.

Speed Sensors

Speed sensors in ABS need to know about the wheel speed which it is about to control it. Speed sensors are on all 4 tires of a car for regulating the car speed.


There is a valve installed in the brake line of every brake which are controlled by the ABS. In various ABS the valve has 3 positions:
  • In the first position, the valve is open and the pressure comes directly from the master cylinder and goes through the brake.
  • In the second position, the valve prevents the line keeping apart the brake from the master cylinder. This is effective in decreasing the pressure from rising.
  • In the third position, the valve releases some pressure from the brake.


Since the valve will release pressure from the brakes, it is necessary that the pressure goes back. The pump reduces the pressure in the line.


The controller controls the car's ABS. It regulates the speed sensors and controls the valves.
ABS brakes do give safety to the car when it faces tough road conditions and it is recommended that cars should be upgraded with ABS.