How to Repair Air Brakes

What You'll Need
Crescent wrench
Methyl alcohol
Rubber mallet
Pry bar

Air brakes can be the difference between life and death. If you have a truck or other large vehicle, every minute it is in the shop can mean a loss of profit for you. Rather than spending time and money on a mechanic, follow these easy steps to repair your air brakes on your own.

Step 1 – Inspect Your Brake System

There are multiple things that can go wrong with an air brake system. Before making a assumption that might cost you time or money, you should check the system and locate exactly where there might be a problem. To begin this check, leave your engine running and allow the air compressor governor to raise the system's air pressure. Depress the parking brake button, then listen for the sound of escaping air or unfamiliar noises coming from the compressor. If you find problems with air pressure that increases, but doesn't build up enough to activate your truck's brakes, you may need to make repairs at the compressor.

Step 2 – Make Compressor Adjustments

If your compressor belt is loose, use a wrench to tighten the compressor's adjustment bracket which will allow the compressor to develop increased air pressure in the brake lines. A loose compressor belt will sometimes raise air pressure but still not activate the brakes because the pressure is not high enough. So, now if you've created an adequate increase in air pressure, you can test the brakes to see if they work properly.

Step 3 – Check for Ice Jams in your System

In cold and icy conditions ice and snow jammed into your braking system can freeze up the braking system's operation. It can cause leaks, or can jam a brake drum. By using a heavy rubber mallet to pound on the brake drums you can sometimes knock off chunks of ice or snow that are jamming them.

Step 4 – Examine Air Line Connectors and Adapter Seals

Ice and snow buildup can also cause problems with proper seating of air line connectors. You can often fix this by cleaning the connectors. Then check rubber seals on the tractor's adapter or on air lines. If the seals appear to be damaged, try using a lubricant to help seal them better. If they are badly damaged, you'll want to replace the adapter on the air line that connects to the tractor, or the adapter on the trailer's air line.

Step 5 – Do a Final Test

After following the procedures recommended above, it will be time to test your brakes again. Inside your cab, use the brake controls to test the parking brakes and driving brakes. Then check the compressor to be sure it is producing needed air pressure.