Why do some trucks use air brakes?

Some trucks use air brakes that give them a signature hiss whenever they come to a stop. Braking systems are an essential part of every vehicle; it becomes more important when it comes to heavy trucks.

Air brakes in heavy trucks make it easier and more convenient to use in the braking system. But why do some trucks use air brakes in their brake system instead of traditional hydraulic brakes? Find it out in this article!

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How Does an Air Brake Work?

A governor controls the controlled pressure that a compressor uses to fill storage tanks. If, in any case, the compressor leaks, the air tanks will stay intact since a valve ensures that air can only flow in one direction via the line.

To move several cams, rods, and brake components as required while driving, the air is delivered via the brake lines, after which it is compressed by pressing the brake pedal. 

Although compressed air tanks are in the truck, the brakes may still stop the truck if the compressor malfunctions. 

This is because there is enough air in the system to allow the brakes to stop the fleet even if the compressor becomes detached from the motor’s side or the system stops working. Thus, keeping replacement parts for air brakes handy can help if there is a need for them.

Why do Some Trucks Use Air Brakes?

Heavy trucks need huge force to stop, and hydraulic brakes take a lot of effort to pedal the brake whenever there is a need to stop. 

On the other hand, air brakes make it more convenient with their use of compressed air. In addition, it keeps the engaging brakes open, so drivers can effortlessly push the pedal to stop.

Air brakes make it safer for trucks because they have a greater stopping power compared to hydraulic brakes. In addition, if there is a leak in brake lines and pressure drops to the minimum level, air brakes will automatically raise it.

As more air is taken in through the compressor since air brakes are powered by air, the chances of tiny leaks are quite low. It means that even a tiny leak won’t stop the system from working. 

However, leaks cause ongoing losses with hydraulic systems, with no fluid being added to make up the difference. So, it must be taken to the repair shop to fix it.

Air brakes make use of an emergency system that utilizes very powerful springs behind the pistons. These pistons stretch out and keep the entire drive wheels in place until an air pressure of roughly 65 psi pulls the pistons back into their driving position.

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Advantages of Using Air Brakes in Heavy Trucks

Apart from safety and convenience, air brakes offer several advantages. Some of them include:

  • In contrast to hydraulic fluid, which has to be refilled and has the potential to leak and cause the brakes to fail, compressed air can be created continuously.
  • Air brakes rely on an active supply of air. Since air is available constantly from the atmosphere, it ensures that they never go out of supply.
  • In instances where trailers are often connected and detached, air brakes are extremely useful. Air brakes make it convenient to attach and detach trailers from the truck.
  • Air brakes can still function well even when there is a sizable amount of brake line leakage. In addition, a mechanical fail-safe is often built into air brakes so that the fleet may be stopped safely using the parking brake in the case of a malfunction.


Air brakes are mostly used by heavy trucks that carry huge loads. As such, these trucks need a brake system that is easy to pedal when the driver wants to stop. Air brakes offer many benefits to semi- and heavy trucks.

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