Adjusting trailer surge brakes correctly is a crucial safety measure that ensures consistent stopping power and prevents accidents while towing. The key lies in maintaining the proper free-play in the actuator and ensuring the brake shoes are correctly positioned within the drums or calipers. This article provides a detailed, step-by-step guide to properly adjusting surge brakes, along with expert tips to troubleshoot common issues and maintain optimal performance.
Understanding Surge Brakes and Their Adjustment
Surge brakes, also known as hydraulic override brakes, rely on the inertia of the trailer pushing forward against the tow vehicle when braking. This forward force compresses a master cylinder in the trailer’s actuator, which then hydraulically applies the trailer’s brakes. Proper adjustment is critical for several reasons:
- Safety: Correct adjustment ensures the trailer brakes engage proportionally to the tow vehicle’s braking, preventing jackknifing and loss of control.
- Performance: Improperly adjusted brakes can result in weak braking, excessive wear, or even brake lockup.
- Longevity: Maintaining proper adjustment extends the lifespan of the brake components, saving you money on repairs and replacements.
Step-by-Step Guide to Adjusting Surge Brakes
The specific adjustment procedure may vary slightly depending on the brand and type of surge brake system. However, the general principles remain the same. Here’s a comprehensive guide:
1. Safety First: Preparation and Precautions
- Chock the wheels of both the tow vehicle and the trailer.
- Disconnect the trailer from the tow vehicle’s hitch ball.
- Ensure the trailer is on a level surface.
- Wear safety glasses and gloves to protect yourself.
- Consult the trailer and brake manufacturer’s manuals for specific instructions and torque specifications.
2. Inspect the Brake System
Before making any adjustments, thoroughly inspect the entire brake system for damage or wear:
- Brake Lines: Check for leaks, cracks, or corrosion. Replace any damaged lines.
- Brake Pads/Shoes: Inspect the thickness of the brake pads or shoes. Replace them if they are worn beyond the manufacturer’s recommended limit.
- Brake Drums/Rotors: Examine the drums or rotors for scoring, cracks, or excessive wear. Resurface or replace them if necessary.
- Actuator: Inspect the actuator for damage, leaks, or excessive play. If the actuator is faulty, it may need to be rebuilt or replaced.
- Master Cylinder: Check the fluid level in the master cylinder. If it’s low, inspect the entire system for leaks.
3. Adjusting the Actuator (Free-Play Adjustment)
The actuator’s free-play is the amount of travel the actuator rod has before it begins to apply pressure to the master cylinder. This adjustment ensures the trailer brakes aren’t constantly engaged.
- Locate the Adjustment Bolt: Most surge brake actuators have an adjustment bolt located on the actuator rod. This bolt is often secured with a lock nut.
- Loosen the Lock Nut: Use a wrench to loosen the lock nut.
- Adjust the Bolt: Turn the adjustment bolt to adjust the free-play. The amount of free-play required varies by manufacturer, but a good starting point is 1/8″ to 1/4″. Refer to your manual for the correct specification.
- Tighten the Lock Nut: Once the free-play is properly adjusted, tighten the lock nut securely.
4. Adjusting the Brakes at the Wheels
This process involves adjusting the brake shoes or calipers at each wheel. There are two main types of brakes: drum brakes and disc brakes.
Adjusting Drum Brakes
- Locate the Adjuster: Drum brakes typically have an adjuster located on the backing plate. This adjuster is usually a star wheel or a self-adjusting mechanism.
- Use an Adjustment Tool: Use a brake adjustment tool to turn the adjuster. Turn the adjuster in one direction until the brake shoes are tight against the drum. You should hear a scraping sound as you turn the wheel.
- Back Off the Adjuster: Back off the adjuster a few clicks until the wheel turns freely but the brake shoes are still close to the drum. The wheel should turn with a slight drag.
Adjusting Disc Brakes
- Disc brakes are generally self-adjusting and do not require manual adjustment unless the calipers are sticking or the brake pads are excessively worn.
- Inspect the Calipers: Check the calipers for proper movement and lubrication. If the calipers are sticking, they may need to be cleaned or rebuilt.
- Ensure Proper Pad Clearance: Confirm that the brake pads are close to the rotor but not dragging.
5. Test and Fine-Tune
After making the adjustments, it’s crucial to test the brakes to ensure they are working properly.
- Connect the Trailer: Reconnect the trailer to the tow vehicle.
- Perform a Low-Speed Test: Drive the tow vehicle and trailer at a low speed and apply the brakes gently. Observe the trailer’s braking performance. The trailer brakes should engage smoothly and proportionally to the tow vehicle’s brakes.
- Adjust as Needed: If the trailer brakes are grabbing, locking up, or not engaging properly, repeat the adjustment process until the desired performance is achieved.
- High-Speed Test: Perform a high-speed test in a safe and controlled environment. Observe the trailer’s braking performance at higher speeds. Make any necessary adjustments.
Troubleshooting Common Surge Brake Issues
Even with proper adjustment, surge brakes can sometimes experience problems. Here are some common issues and potential solutions:
- Brakes Locking Up: This can be caused by excessive actuator free-play, a sticking actuator, or seized brake components.
- Weak Braking: This can be caused by insufficient actuator free-play, worn brake pads/shoes, or air in the brake lines.
- Noisy Brakes: This can be caused by worn brake pads/shoes, scored brake drums/rotors, or loose brake components.
- Jerky Braking: This can be caused by a sticking actuator, unevenly adjusted brakes, or worn brake pads/shoes.
Frequently Asked Questions (FAQs)
1. How often should I adjust my trailer surge brakes?
It’s recommended to inspect and adjust your trailer surge brakes at least twice a year, ideally before the towing season and after a period of heavy use. More frequent inspections may be necessary if you frequently tow heavy loads or operate in harsh conditions.
2. What tools do I need to adjust trailer surge brakes?
You’ll typically need a wrench set, a socket set, a brake adjustment tool (for drum brakes), safety glasses, gloves, and possibly a jack and jack stands, depending on the brake system’s access. Always refer to your trailer’s manual for specific tool requirements.
3. How do I bleed air from the brake lines?
Bleeding air from the brake lines is similar to bleeding brakes on a car. You’ll need a helper. Locate the bleeder screws on each brake cylinder. Open the bleeder screw, have your helper pump the brakes, and close the bleeder screw before the pedal reaches the floor. Repeat until no air bubbles are present. Ensure the master cylinder remains full of brake fluid throughout the process.
4. What type of brake fluid should I use?
Consult your trailer and brake manufacturer’s manuals for the recommended brake fluid type. DOT 3 or DOT 4 brake fluid are common choices, but using the wrong type can damage the brake system.
5. How do I know if my actuator is bad?
Signs of a bad actuator include excessive play, leaks, difficulty compressing, or inconsistent braking. A visual inspection and a simple test can help determine if the actuator is functioning correctly. Try compressing the actuator with a pry bar, it should resist and hold pressure.
6. Can I convert surge brakes to electric brakes?
Yes, it’s possible to convert surge brakes to electric brakes. However, this is a more complex project that may require replacing the actuator, adding wiring, and installing a brake controller in the tow vehicle. Consult with a professional mechanic for advice and installation.
7. What causes surge brakes to lock up when backing uphill?
Many surge brake systems incorporate a solenoid valve that prevents the brakes from engaging when backing up. If this solenoid fails or is not properly wired, the brakes may lock up. Ensure the solenoid is functioning correctly and properly wired to the tow vehicle’s reverse lights circuit.
8. Are surge brakes legal in all states?
Surge brakes are generally legal in most states, but it’s always a good idea to check your local regulations to ensure compliance. Some states may have specific requirements for the type and size of trailers that are allowed to use surge brakes.
9. How do I adjust self-adjusting drum brakes?
While advertised as “self-adjusting,” these systems often require manual activation. Typically, repeated stops while backing up will trigger the adjustment mechanism. If your brakes are not self-adjusting properly, you may still need to manually adjust them as described above.
10. What is the purpose of the breakaway cable?
The breakaway cable is a critical safety feature that automatically applies the trailer brakes if the trailer becomes disconnected from the tow vehicle. Always ensure the breakaway cable is properly connected to the tow vehicle and functioning correctly.
11. How do I lubricate my surge brake actuator?
Refer to your trailer’s manual for specific lubrication recommendations. Typically, lubricating the actuator involves applying grease to the moving parts, such as the pivot points and the actuator rod. Use a high-quality marine grease to prevent corrosion.
12. Can I adjust my trailer surge brakes myself, or should I take it to a professional?
While adjusting surge brakes is something a handy DIYer can typically handle, if you lack experience or are unsure about any step of the process, it’s always best to consult a qualified mechanic. Improperly adjusted brakes can be dangerous and could lead to accidents.