While most cars and other non-commercial vehicles use hydraulic brake systems, the majority of trucks and vans used for commercial purposes are equipped with air brakes. While there are some similarities between the two – they both work to stop a moving vehicle, for instance – there are some major differences between the systems and how they operate. Read on for Air Brakes 101.
How do Air Brakes Work?
Air brakes rely on – big surprise – air to stop the vehicle. This pressurized air is stored in tanks and pumped to the brakes by an air compressor when the driver applies the brakes. The air compressor governor controls the amount of air delivered from the reservoir tanks to ensure the proper amount is supplied. Some trucks are also equipped with emergency air brakes or an exhaust brake. Emergency air brakes are activated by a button on the dash, which triggers a delivery of air into the system. When this air is in the place, the emergency brake remains free. Exhaust brakes can be found on some heavy trucks to aid in braking, but these are actually part of the engine and not the brake system.
How is an Air Brake System Different for Drivers?
For drivers, using an air brake system for the first time can seem very strange because it so different from standard hydraulic systems. For example, stopping is a slower process, with pressure applied to the brake pedal slowly and methodically. Drivers must also check the air pressurization system to ensure tanks and the system overall is functioning properly. It is also never appropriate to “pump” the brakes when driving a vehicle with an air brake system, as this will actually deplete the air and drain the system.
Why Air Brakes?
There are a few reasons why air brakes are used for so many commercial trucks and vans. For starters, air is unlimited and minor air leaks do not affect the overall system, as can happen with hydraulic systems that rely on fluid. This is a great fail-safe for larger vehicles, as they can operate (and stop) even when air is leaking. Air brakes also provide more versatility, as they are better equipped to handle different types of terrain than hydraulic brakes.