How To Bleed Surge Brakes On Trailer

How to Bleed Surge Brakes on a Trailer

Surge brakes are a common type of braking system used on boat trailers, utility trailers, and other towed vehicles. Unlike electric or hydraulic brakes, surge brakes rely on the inertia of the trailer to activate the braking mechanism. While generally reliable, they can sometimes require bleeding to ensure optimal performance. This guide will walk you through the process of bleeding surge brakes on your trailer.

Understanding Surge Brakes

Before you begin bleeding, it's important to understand how surge brakes work. They utilize a mechanism within the coupler that connects the trailer to the tow vehicle. When the tow vehicle stops suddenly, the momentum of the trailer pushes hydraulic fluid through a valve, activating the brakes on the trailer wheels. Air can become trapped in this system, hindering its effectiveness. Bleeding removes this trapped air and restores proper brake function.

Tools You'll Need

Before you start, gather the necessary tools:

• A wrench: The correct size will depend on the type of bleeder valve on your trailer brakes.
• A clear tube: This tube will allow you to see the fluid flow and identify when air bubbles are present.
• A container: To collect the old brake fluid.
• New brake fluid: Use the type specified in your trailer's owner's manual. Never use anything other than the recommended fluid.
• Gloves: Protect your hands from the brake fluid.
• Shop rags: To clean up any spills.

Steps to Bleed Surge Brakes

Safety First: Always engage the parking brake on your tow vehicle and chock the wheels of both the tow vehicle and the trailer before starting this procedure.

1. Locate the Bleeder Valves: These valves are typically located on the brake calipers of each wheel. They are usually small and have a threaded opening.
2. Connect the Tube: Attach one end of the clear tube to the bleeder valve and submerge the other end in the container of brake fluid. This prevents air from entering the system.
3. Open the Bleeder Valve: Carefully open the bleeder valve using the wrench. You'll likely need to crack it open slightly and then keep it open just enough for a slow and steady flow of fluid.
4. Pump the Brakes (Optional): Some recommend gently pumping the tow vehicle's brakes to help move the fluid through the system. This step might not be necessary, but could assist in a faster bleeding process. Be very gentle to avoid creating pressure that could damage the braking system.
5. Observe the Fluid: Watch the fluid flowing through the tube. Initially, you'll likely see air bubbles. Continue until the fluid runs clear and consistently free of air bubbles.
6. Tighten the Bleeder Valve: Once the fluid is clean, carefully tighten the bleeder valve.
7. Repeat for Each Wheel: Repeat steps 2-6 for each wheel on the trailer. It's generally best to bleed the brakes starting with the wheel furthest from the surge brake actuator and working your way closer.
8. Check Fluid Level: After bleeding all wheels, check the fluid level in the surge brake reservoir and add fluid as needed. Refer to your trailer's manual for the correct fluid level.
9. Test the Brakes: Before operating the trailer, test the brakes to ensure they are functioning correctly. This is crucial for safety reasons.

Troubleshooting

If you're having trouble bleeding the brakes, it could be due to a few reasons:

• Clogged lines: A blockage in the brake lines can prevent the fluid from flowing properly. This requires professional attention.
• Faulty bleeder valve: A damaged or faulty bleeder valve might not seal properly. Replacement might be required.
• Low fluid level: Ensure the brake fluid reservoir is adequately filled before attempting to bleed the brakes.

Disclaimer: This guide provides general information and might not apply to all surge brake systems. Always refer to your trailer's owner's manual for specific instructions and safety precautions. If you're unsure about any part of this process, consult a qualified mechanic. Incorrect bleeding can compromise the safety of your braking system. Always prioritize safety.