Surge brakes, a common braking system on trailers, function by utilizing the inertia of the trailer pushing against the tow vehicle during deceleration. Proper adjustment ensures optimal braking performance, safety, and longevity of the system. This guide provides a comprehensive understanding of how to adjust surge brakes effectively, ensuring your trailer stops safely and reliably.
Understanding Surge Brake Mechanics
Before diving into the adjustment process, it’s crucial to grasp the fundamental principles behind surge brake operation. These brakes rely on the momentum of the trailer to activate. As the tow vehicle slows down, the trailer’s forward motion compresses a master cylinder located within the actuator (the part of the trailer hitch that slides). This compression forces brake fluid through brake lines to the wheel cylinders or calipers at each wheel, applying the brakes.
The effectiveness of surge brakes depends heavily on proper adjustment. When correctly adjusted, the brakes should engage smoothly and proportionally to the braking force applied by the tow vehicle. If they are too loose, braking will be weak and delayed. If they are too tight, the brakes may drag, causing excessive wear and potentially leading to overheating and failure.
Preparing for Surge Brake Adjustment
Safety is paramount when working on any braking system. Before you begin, ensure the trailer is securely parked on a level surface, with the wheels properly chocked.
Gathering Necessary Tools and Materials
You’ll need the following tools and materials:
- Jack and Jack Stands: To safely lift and support the trailer wheels.
- Wrench Set: To adjust brake components. The specific sizes will vary depending on the trailer.
- Screwdrivers: Both flathead and Phillips head screwdrivers may be needed.
- Brake Adjustment Tool: This specialized tool simplifies the adjustment process, especially for drum brakes.
- Brake Cleaner: To clean brake components.
- Brake Fluid: Matching the type specified for your trailer.
- Safety Glasses: To protect your eyes.
- Gloves: To protect your hands.
- Torque Wrench: To tighten fasteners to the correct specifications.
- Service Manual: Refer to your trailer’s service manual for specific instructions and torque values.
Identifying the Brake Type
Surge brakes can be either drum brakes or disc brakes. The adjustment procedure varies slightly depending on the brake type. Identifying the type is essential before proceeding. Drum brakes are typically enclosed within a metal drum, while disc brakes feature an exposed rotor.
Adjusting Surge Brakes: Step-by-Step Guides
The following sections outline the adjustment procedures for both drum and disc surge brakes. Always consult your trailer’s service manual for specific instructions and torque values.
Adjusting Drum Surge Brakes
- Lift and Secure the Trailer: Use a jack to lift the trailer wheels off the ground, then support the trailer with jack stands.
- Locate the Adjustment Slots: On the backside of the brake backing plate, you’ll find adjustment slots. These slots are usually covered by rubber plugs. Remove the plugs to access the adjuster wheel.
- Adjust the Brakes: Using a brake adjustment tool or a flathead screwdriver, turn the adjuster wheel. Typically, turning the wheel upward expands the brake shoes, while turning it downward retracts them.
- Adjust Until Drag: Adjust the brakes until you feel a slight drag when rotating the wheel by hand. The wheel should turn freely but with noticeable resistance.
- Back Off the Adjustment: Back off the adjuster wheel slightly (typically 6-8 clicks) until the wheel spins freely without any drag.
- Repeat for All Wheels: Repeat the adjustment process for all wheels.
- Test the Brakes: Lower the trailer and test the brakes in a safe, controlled environment. Ensure the brakes engage smoothly and evenly.
Adjusting Disc Surge Brakes
Disc brake adjustment is generally simpler than drum brake adjustment. Most disc brake systems are self-adjusting. However, certain components may require manual attention.
- Inspect Brake Pads: Visually inspect the brake pads for wear. Replace them if they are worn thin.
- Check for Binding: Ensure the caliper slides freely on its mounting bolts. If the caliper is binding, clean and lubricate the bolts.
- Adjust Actuator Rod (if applicable): Some surge brake systems have an adjustable actuator rod. This rod connects the actuator to the master cylinder. Adjusting the rod length can affect the brake engagement point. Consult your trailer’s service manual for specific instructions on how to adjust the actuator rod.
- Bleed the Brakes (if necessary): If the brakes feel spongy or weak, air may be trapped in the brake lines. Bleeding the brakes will remove the air and improve braking performance.
- Test the Brakes: After making any adjustments, test the brakes in a safe, controlled environment.
Maintaining Surge Brakes
Regular maintenance is essential for ensuring the continued performance and safety of your surge brakes.
Regular Inspections
- Inspect brake lines for leaks or damage.
- Check brake fluid level and condition.
- Examine brake pads (for disc brakes) or brake shoes (for drum brakes) for wear.
- Inspect the actuator for signs of damage or corrosion.
Brake Fluid Management
- Use the correct type of brake fluid specified for your trailer.
- Flush and replace the brake fluid every two years, or as recommended by the manufacturer.
Actuator Maintenance
- Grease the actuator slide regularly to ensure smooth operation.
- Inspect the actuator for corrosion and damage.
Surge Brake FAQs
Here are 12 frequently asked questions about surge brakes, offering further insights and practical advice:
1. How often should I adjust my surge brakes?
Regularly, ideally before each trip and after any significant change in load. However, a good practice is to check them at least every 3,000 miles or every six months, whichever comes first. Pay attention to any changes in braking performance, which could indicate the need for adjustment.
2. How can I tell if my surge brakes are not adjusted correctly?
Common signs include: weak or delayed braking, brakes dragging or overheating, uneven braking between wheels, and excessive noise during braking.
3. What type of brake fluid should I use in my surge brake system?
Refer to your trailer’s service manual for the recommended brake fluid type. Typically, DOT 3 or DOT 4 brake fluid is used. Never mix different types of brake fluid.
4. Can I convert my surge brakes to electric brakes?
Yes, it is possible, but it’s a significant undertaking. It involves replacing the actuator, adding an electric brake controller in the tow vehicle, and wiring the trailer for electric brakes. Consulting a qualified mechanic is highly recommended.
5. What causes surge brakes to lock up?
Several factors can cause surge brakes to lock up, including a malfunctioning actuator, corroded or damaged brake components, and incorrect brake adjustment. Overfilling the actuator with grease can also contribute to lockup.
6. How do I bleed my surge brakes?
Bleeding surge brakes is similar to bleeding hydraulic brakes on a car. You’ll need a helper, a wrench, a clear hose, and a container. Open the bleeder valve on each wheel cylinder or caliper, one at a time, and have your helper press the actuator rod in and out. Close the bleeder valve before releasing the actuator rod. Repeat this process until no air bubbles are visible in the brake fluid.
7. Why are my surge brakes squeaking?
Squeaking brakes can be caused by several factors, including worn brake pads or shoes, glazed brake rotors or drums, and loose brake components. Cleaning or replacing the affected parts is often necessary.
8. How do I grease my surge brake actuator?
Locate the grease fittings on the actuator and use a grease gun to inject grease until it begins to seep out. Avoid over-greasing, as this can cause the actuator to malfunction. Use a marine-grade grease for better water resistance.
9. What is the purpose of the breakaway cable on my surge brake trailer?
The breakaway cable is a crucial safety feature. If the trailer becomes detached from the tow vehicle, the cable will pull a pin on the actuator, activating the trailer brakes and preventing a runaway trailer.
10. My trailer brakes are dragging. What should I do?
Dragging brakes can be caused by several factors, including overtightened brake adjustment, corroded or damaged brake components, and a malfunctioning actuator. Inspect the brake components and adjust the brakes as needed.
11. Where can I find replacement parts for my surge brake system?
Replacement parts can be found at trailer supply stores, auto parts stores, and online retailers. Be sure to purchase parts that are compatible with your specific surge brake system.
12. Are surge brakes legal in all states?
Yes, surge brakes are generally legal in all states for trailers that meet certain weight requirements. However, it’s always a good idea to check your local regulations to ensure compliance.
By understanding the principles of surge brake operation and following these adjustment and maintenance guidelines, you can ensure your trailer brakes are functioning optimally, providing you with a safe and reliable towing experience. If you are unsure about any aspect of surge brake maintenance or adjustment, consult a qualified mechanic.