truck Lorry air brakes

What Are Lorry Air Brakes and How Do They Work?

Heavy trucks transport tens of thousands of pounds of cargo. When combined with the vehicle’s weight, the amount of stopping power required from the brakes can seem extraordinary. This is where lorry air brakes come into the picture. Air is available in plenty and hydraulic brake fluid is vulnerable to leakages. So, air-powered brakes offer a reliable way to keep the vehicle, driver, and others safe on the road.

Lorry air brakes are a critical component. Whether you are a vehicle operator or owner, it is important to know how these systems work.

Components of a Lorry Air Brake System

The air brake system has several key components that work together to ensure effective, efficient, and safe braking.

  • Air Compressor: The air compressor pressurizes air, which then gets stored in reservoir tanks.
  • Governor: The governor is responsible for controlling the compressor. It regulates air pressure, maintaining it within certain limits.
  • Brake Pedal: When the driver depresses the brake pedal, the air pressure is released from the reservoir tanks via valves and hoses. This air then reaches the brake chambers.
  • Brake Chambers: Brake chambers transform the air pressure into mechanical force. This activates the brake pads/shoes against the drum or rotor, causing the truck to slow down. 

The overall reliability of a lorry’s air brake system depends on its maintenance and the proper synchronization of all the different parts.

How Do Lorry Air Brakes Work?

The safe operation of air brakes requires that you understand how these systems work. Here is how this system works:

  • The air compressor pumps air into the reservoir tanks. These tanks are positioned beneath the vehicle.
  • The air is then compressed and moved through the air brake lines that take it to the air brake. In S-cam brake systems, when the operator pushes the brake pedal, the air pressure pushes a rod out to move the slack adjuster.
  • This slack adjuster works by calibrating the brake system. It ensures the internal spring system works properly.
  • The compressed air flows via the nozzle to the air brake chamber. The spring then moves the S-cam.
  • The brake shoe linings are forced by the S-cam to move away from one another. The shoe linings then press from inside against the brake drum.
  • When the shoe linings press against the brake drum, this creates the friction required for slowing down the vehicle.

The brake shoes are similar to brake pads in that they wear out over time. The rate of deterioration increases when the brake pedal is used too often and too heavily. It is recommended to maintain your vehicle’s brake shoes at a minimum thickness of 1/4 inch.

Your fleet’s brakes should be regularly and consistently checked to ensure that no components malfunction or become unsafe. 

Air Brake System Maintenance Tips

Regular and proper air brake maintenance is crucial.  It is recommended to follow these tips to ensure this system keeps working effectively whether you have a single truck or a fleet of commercial vehicles:

  • Check for any signs of valve failure in the circuits. This can be checked from the drain valve on the wet tank. 
  • Check the glad hands for dirt, salt, or debris build up.
  • Check the rubber boots and seals of the ABS connection system.
  • Check the push rod actuation in the brake chambers, especially for weak or brake springs.
  • Make sure the slack adjusters and pushrods are properly working.
  • Check the parking brakes for damaged parts or leaks in the chambers.

You cannot afford not to maintain the critical parts of your vehicles. Any crashes leading to failed brake system maintenance can hold you liable. Besides following the above-mentioned tips, it is important to monitor driving habits. Drivers must maintain safe speeds while maintaining safe following distances. This reduces the strain on the brake system if the vehicle needs to be stopped suddenly. It is also important to check and maintain proper tire pressure.

If you need any type of heavy truck maintenance or repair services for your lorry air brakes, you can rely on TMS TruckMasters. Reach out to our team at (514) 631-0963 in Montréal (St-Laurent), (450) 455-2578 in Vaudreuil-Dorion, or (450) 645-0404 in Boucherville.