Many a trainee has climbed behind the wheel of a truck on his/her first day of road instruction only to be frustrated beyond belief by not being able to get the vehicle moving. After several embarrassing stops and starts, new drivers have to be instructed about air brakes. Why? Because the design of air brakes will prevent a truck from moving if you don’t give them time to recharge.
A typical air brake system is a triple-valve system that consists of air brake hose, pumps, pressurization valves, and storage tanks. It is a system invented by an engineer named George Westinghouse in the late 19th century. It works as follows:
1. System Charge – The key to air brakes is a full storage tank. In order for the brakes to release, the system must be fully pressurized, meaning the storage tank must be full of air.
2. Brake Application – It is the release of pressurized air that causes brakes to deploy. The more air released, the more solidly brake pads grip their rotors. That means the application of the brake pedal essentially releases air from the pressurized tank.
3. Release and Recharge – The brake system will continue releasing air as long as the driver continues pressing the brake pedal. Releasing the brake pedal immediately causes the system to begin recharging again, releasing the brakes as air pressure builds.
All of this happens in a split second – with air traveling through air brake hose in both directions. A properly functioning system is not remarkably different from hydraulic brakes in its practical application, but air brakes do feel quite a bit different from a user standpoint.
What fools new truck drivers is the fact that the air brake systems do not automatically release. With hydraulic brakes, depressing the brake pedal forces hydraulic fluid into the brakes; releasing the pedal forces fluid back out. Air brakes are different. They remain deployed until the system starts to recharge. That’s why new truck drivers who don’t understand how they work don’t give their vehicles enough time to recharge the brakes before attempting to drive away.
Regular Equipment Inspections
Another thing new drivers need to learn about air brakes is the necessity of regular equipment inspections. Just one small breach of an air brake hose can make all the difference in the world for pressurizing the system. It doesn’t take much to lock your brakes up by way of escaping air.
Hoses, belts and air tanks should be inspected regularly to make sure they are working properly. The air brake hose itself needs to be free of wear and tear, especially surface damage and worn couplings. It is also a very good idea to keep a few lengths of hose and some spare couplings in your toolbox. Breaking down in the middle of a trip because one of your air hoses broke is an easy way to frustrate yourself waiting for a mechanic, especially since replacing hoses is so simple to do.
Mytee Products now carries a selection of air brake hose, coils, and other related equipment. We invite you to browse our entire inventory at your earliest convenience. If we don’t have what you need, please contact us and inquire anyway. We might be able to help locate items we don’t currently carry.
Remember, your air brakes will not work properly if your hoses, couplings and air tanks are not all in good working condition. This is true whether you are a brand-new driver or a seasoned veteran with years of experience. So get to know your braking system and check it regularly.