Airbrake systems: How they work in your heavy vehicle

Trucks are very heavy vehicles, and when it comes to stopping, they need some serious power to make sure they are able to do so safely. Air brakes are able to absorb the energy generated by the vehicle when it is trying to stop. Ever wondered why trucks make that hissing noise when they come to a halt? That’s the air brakes in effect, releasing a build-up of excess pressure in the system. It is crucial you keep your air brakes in working order to ensure not only your own safety, but the safety of other vehicles as well.

How do they work?

The beauty of air brakes is not only their durability, but also their ability to withstand the high pressure and heat generated when a heavy vehicle stops. Truck air brakes consist of a combination of three braking systems: 

• Service brakes: these are the truck brakes used in regular driving and are controlled by the foot treadle. By activating the truck’s service brakes, you are signalling to put the brakes on, and air pressure will begin to reduce within the supply tanks, causing the truck’s brakes to release.
• Park brakes: this system is activated when the vehicle comes to a complete stop and is used to secure your vehicle when it is parked.
• Emergency brakes: this brake system uses a combination of the park and service brakes. The emergency brakes, as the name suggests, become activated if there is a failure in one or both of the other braking systems in order to stop the truck or heavy vehicle.

Your truck’s air brake system is made up of several key components all acting to ensure your truck is able to stop safely.

• Compressor: this component is constantly running as it is driven by the engine. Its purpose is to pump, store and replenish the air required in the brake system and keep the pressure at a certain level.
• Check and control Valves: monitor the levels of air in the various brake systems to ensure there is air in their supply tanks.
• Dryer Filter: removes the impurities from the air allowing it to enter the system and fill the supply tanks
• Reservoir (supply) tanks: where the air is stored and used to create pressure in the system.​
• Foot treadle: similar to how the brake pedals work in other cars, the foot treadle cause air to reduce in the service line allowing your truck to brake. Located near the clutch and accelerator, this is used as an indicator to others road users that you intend to brake (aka turns on your brake lights). 

How to keep your air brake system operating smoothly. 
It is important to ensure your air brake system is working correctly to ensure your vehicle is able to stop safely. If you are experiencing an issue with your air brake system, contact your diesel mechanic to have an expert inspect the problem. At Diesel West Mechanic Services, we provide mobile diesel engine servicing throughout the Perth metro area and to regional areas upon request. Our experienced diesel mechanics are experts at fault diagnosis and repair so you can be assured your diesel engine will perform at its best. 

Whether it’s trucks and trailers or civil and construction equipment, Diesel West make things easier for you. For mobile diesel engine repairs and servicing, contact Diesel West Mechanical Services today on 0427 501 378 or fill in our online contact form.