Skip to content
Air Brakes System

Understanding The Functionality Of Air Brake System in Automobile

Brakes are one of the important components of any car. If you wish for a powerful engine to start and run your car, you may require a powerful brake to stop it or decelerate the same. Modern-day cars use hydraulic brake systems to slow down or stop the vehicle. However, the air brake system is now gaining popularity among car owners and car manufacturers.

How do Air Brakes work?

A compressed air brake system uses compressed air as opposed to a hydraulic system that uses hydraulic fluid or oil as a medium. It then applies necessary pressure to the master cylinder piston, which presses the brake pad to assess in stopping or slowing down of the vehicle.

The Air brake system comprises various components like an air compressor, air compressor governor, brake pedal, dirt collector, air dryer, brake valve, brake drums, and air storage. Each of these components performs a particular function to help the air brake system run effectively.

A Detailed Understanding Of How The Air Brake System Function In Your Vehicle:

#1 – Engine and Brake Pedal:

Car Brake Pedal

When a car is started with the help of the engine, the brake compressor will also start, as it is directly operated by the engine. It starts compressing the atmospheric air and with the help of the compressor governor, this compressed air reaches the air reservoir, which has some air stored from last use.

Now when the driver presses the brake pedal, the outlet valve of the brake closes and the inlet valve opens up. This then provides the necessary passage for the compressed air to pass from the reservoir to the brake line of the system. This is the first step to understanding how an Air Brake system operates.

Also Read: Hand Tools – A Must For Maintaining Your Car

#2 – The Brake Cylinder:

Brake Cylinder

The next step in the process is that the compressed air flowing through the brake line is then transferred to the brake cylinder which contains a piston inside. The compressed air applies pressure over the piston inside the brake chamber, giving way to the piston moving from its original position. This movement then converts pneumatic energy into mechanical energy.

#3 – The Brake Pads:

Brake Pads

The brake drums are placed inside the wheel end of the brake cylinder, there is a mechanical actuator with springs or slacks with brake pads on the outer end. It is how the air brake system in your car works.

Basic Difference Between Air Brakes and Hydraulic Brakes:

  1. One of the key differences between Air Brakes and Hydraulic Brakes is that compressed air is used as a working material in Air Brakes whereas Hydraulic Brakes use Hydraulic fluid or oil.
  2. The second key difference which makes Air Brakes much better than Hydraulic Brakes is that Air Brakes are way more powerful than Hydraulic Brakes.
  3. The major components in Air Brakes are the Air compressor, unloader valve, brake valve, and brake chamber. Whereas major components in Hydraulic Brakes are the Master cylinder, wheel cylinder, and oil reservoir.
  4. Air Brake systems because of their power system are found to be used in heavy vehicles such as buses, trucks and trains. Whereas Hydraulic Brake systems are used in Light vehicles such as cars, light-duty trucks, etc.
  5. Another major difference between these two brake systems is that the air compressor uses a certain amount of engine power whereas no engine power is used in Hydraulic Brakes.

Also Read: Green Number Plates – Know Everything About Electric Vehicle Plates in the UK

The Main Reason, We Require Air Brake System:

A powerful brake system is extremely important in any automobile vehicle but as we all know applications for different vehicles i.e. heavy utility vehicles and light utility vehicles are different.

  1. A load of light vehicles and heavy vehicles is different and hence the braking system required is also different. Heavy vehicles are needed to be equipped with a braking system that is powerful enough to provide enough braking force that can stop or slow down the vehicle.
  2. Hydraulic brakes provide enough force to stop or slow down the vehicle due to its short dimension but the same will not prove successful in a heavy vehicle. Hence, for this reason, hydraulic brakes are not very effective in heavy utility vehicles. Heavy utility vehicles require the power that the Air Brake System supports.
  3. The size of the components of the Hydraulic Brake System needs to be increased with the increase in the size of the vehicle. This makes it very difficult to install in a heavy utility vehicle. This issue is resolved in the Air Brake System.
  4. For reasons of safety and efficiency, it has now been made compulsory by the government to use only the Air Brake System for heavy utility vehicles.


Thus, in the end, it is safe to conclude that the Air Brake system not only helps in slowing down and speeding vehicles but also prevents accidents. The Air Brake System is not only safer but also more efficient as compared to the conventional Hydraulic Brake System and a must for heavy utility vehicles but not really necessary for light utility vehicles. If you are looking for car parts and accessories online in the UK, Connect with Leicester Motor Spares.