Three Things That Can Go Wrong With Your Semi-Truck’s Air Brakes

You don’t need us here at Fleet Truck & RV Repair to tell you what could happen if you lose your air brakes. We service and repair these braking systems all the time to ensure that never happens. Pretty much every semi-truck on the road has an air brake system, and there are three common problems we see in our Montana truck and RV service shop every day. Here’s what they are so you can look out for them and prevent an avoidable accident on your next run.

1. Air Pressure Building Problems

In very basic terms, an air brake system uses pressurized air to stop your rig. The air pressure creates the force needed to brake. If the air brake system’s compressor is failing, it might not be able to force enough air pressure into the compression reservoir and your brakes will fail. When you step on the brake pedal, the air in the pressure reservoir is transferred through the brake lines to the brakes to slow down and stop your rig. The compressor must then fill the reservoir again quickly to ensure you always have enough air pressure in your rig’s brake system. A failing air compressor cannot do that.

2. Leaking Air Pressure Through the Valves

The air compressor isn’t the only thing that can cause your air brakes to lose much-needed air pressure. The reservoir can also lose the air pressure the compressor is pumping into it through leaking valves. These valves are responsible for regulating the flow of air that comes out of the reservoir and into the braking system. You probably learned how to test this leakage in truck driving school, so you know what we’re talking about. If you didn’t, stop by our shop and we’ll show you how to do the test the valve pressure. When you test your air brakes, you shouldn’t have more than 2 psi per minute leaking out of the valves. If you do, bring your rig in for repair. The valves are leaking too much air.

3. Air Reservoir Contamination

The air brake system on your rig has what’s known as an air dryer, and, no, it’s not for your hair. This dryer is responsible for removing oil and water out of the air that is entering the air reservoir. This liquid can cause major problems with your air brakes. The air dryer is a combination of filters designed to trap these fluids so they don’t affect your air brake functionality. One filter stops oil droplets from making their way through to the brake system, while a desiccant bed filter sops up all water vapor. When you drain the air reservoir after a run, check for oil and/or water. If you see some, bring your rig into our shop right away. Water suggests the air dryer is full while oil leaks from damaged piston rings.

We are Fleet Truck & RV Repair, and our truck and RV service shop is located in Great Falls, MT.

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