how to bleed trailer drum brakes

How to Bleed Trailer Drum Brakes

Bleeding trailer drum brakes is an essential maintenance task that ensures your braking system functions effectively and safely. Over time, air can enter the brake lines, leading to a spongy brake pedal and reduced braking performance. Ensuring your trailer's brakes are bled correctly can enhance safety while towing and prolong the life of your braking system. In this guide, we will walk you through the steps necessary to bleed your trailer drum brakes efficiently.

Tools and Materials Needed

Before you begin, gather the following tools and materials

1. Brake Bleeder Kit This can be a one-person bleeder or a two-person kit, which typically includes a fluid reservoir and tubing. 2. Brake Fluid Use the appropriate type of brake fluid specified for your trailer’s braking system (usually DOT 3 or DOT 4). 3. Wrenches For loosening the bleeder valves. 4. Rags or Towels To clean up any spills and to wipe down components. 5. Safety Glasses To protect your eyes from fluid splashes.

Step-by-Step Guide

1. Prepare Your Trailer

Start by parking your trailer on a level surface and ensure that it is securely supported with wheel chocks. Make sure your vehicle is also off and in a safe position, as air might enter the brakes during this process.

2. Locate the Brake Bleeder Screws

Identify the bleeder screws on each drum brake. Typically, there will be one bleeder screw per wheel, located on the top of the brake assembly.

3. Check the Brake Fluid Reservoir

Before bleeding the brakes, check the brake fluid reservoir located in the towing vehicle. Ensure it is filled with fresh brake fluid to the recommended level, as you will need to keep it full to prevent introducing more air into the system.

4. Attach the Bleeder Kit

Attach the tubing of your brake bleeder kit to the bleeder screw on the first wheel you will bleed. Make sure the other end of the tubing is submerged in a small container filled with brake fluid to prevent air from re-entering the system.

5. Begin Bleeding the Brakes

While one person (the bleeder) is working on the brake pedal inside the towing vehicle, another person (the assistant) should be at the wheel. Here’s how it works

- For the Assistant Open the bleeder screw slightly with a wrench while the bleeder pumps the brake pedal. - For the Bleeder Press the brake pedal slowly and firmly, then hold it down. - For the Assistant As the bleeder holds the pedal down, close the bleeder screw. Then instruct the bleeder to release the pedal.

Repeat this process several times (5 to 10 cycles) until you see clear, bubble-free brake fluid flowing through the tubing. Keep an eye on the brake fluid reservoir and top it up as necessary to avoid introducing air.

6. Move to the Next Wheel

Once you have bled the first wheel, repeat the above process for each of the remaining wheels. Generally, you should start with the wheel farthest from the brake master cylinder and work your way to the closest one.

7. Final Checks

After bleeding all wheels, make a final check of the brake fluid level in the reservoir and top it off if needed. Press the brake pedal to ensure it feels firm and responsive.

8. Clean Up and Test

Remove all tools and the bleeder kit, ensuring that no brake fluid has contaminated any vehicle surfaces. Before hitting the road, take your trailer for a short test drive to ensure all brakes are functioning correctly.

Conclusion

Regularly bleeding the brake system of your trailer is crucial for safety and performance. By following these steps, you can ensure your trailer drum brakes are in excellent condition, enabling you to tow with confidence. Always remember that if you're unsure or uncomfortable performing brake maintenance, it's best to consult a professional mechanic. Safe travels!