Adjusting your electric trailer brake shoes is crucial for safe towing and optimal braking performance. The goal is to achieve consistent and even braking across all wheels, preventing wheel lockup and ensuring your trailer follows smoothly behind your tow vehicle. Achieving this balance requires understanding the adjustment process and knowing how to identify properly adjusted brakes. The correct adjustment ensures that the brake shoes are in close proximity to the drum but not dragging, allowing for immediate and effective braking when needed.
Why Proper Electric Trailer Brake Adjustment Matters
Improperly adjusted electric trailer brakes can lead to a multitude of problems, including:
- Reduced braking efficiency: Loose brakes mean longer stopping distances, posing a significant safety risk, especially in emergency situations.
- Uneven braking: One side of the trailer may brake harder than the other, causing the trailer to sway or even jackknife.
- Premature brake wear: Over-tightened brakes can cause excessive friction, leading to rapid wear of the brake shoes and drums. Loose brakes may require much more electrical power to engage, burning out the brake magnet and prematurely wearing the armature surface of the drum.
- Increased fuel consumption: Dragging brakes create unnecessary resistance, forcing your tow vehicle to work harder and burn more fuel.
- Potential for accidents: The cumulative effect of these problems significantly increases the risk of accidents and property damage.
Therefore, regular adjustment of your electric trailer brake shoes is not just a maintenance task; it’s a crucial safety measure.
Tools and Materials You’ll Need
Before you begin, gather the necessary tools and materials. Having everything ready will make the process smoother and more efficient:
- Jack and safety stands: To safely lift and support the trailer. Never work under a trailer supported only by a jack.
- Wheel chocks: To prevent the trailer from rolling while you work.
- Brake adjustment tool (or flat-head screwdriver): For turning the brake adjuster wheel. A specialized brake adjustment tool is recommended for ease of access.
- Gloves: To protect your hands from dirt and grease.
- Shop towels or rags: For cleaning.
- Penetrating oil (optional): To loosen stubborn adjuster mechanisms.
- Torque wrench: To properly tighten lug nuts after reassembling the wheels.
- Owner’s manual: Consult your trailer’s manual for specific instructions and torque specifications.
Step-by-Step Guide to Adjusting Electric Trailer Brake Shoes
Follow these steps carefully to ensure proper adjustment:
- Safety First: Park the trailer on a level surface, engage the parking brake of your tow vehicle, chock the wheels of the trailer on the opposite side of the trailer that you are working on, and disconnect the trailer’s electrical connector.
- Lift and Secure: Using a jack, raise the trailer until the tire is off the ground. Securely support the trailer with safety stands. Never work under a trailer supported only by a jack.
- Remove the Wheel: Remove the lug nuts and carefully remove the wheel.
- Locate the Adjustment Slot: On the backing plate of the brake assembly, you’ll find an oval or rectangular slot. This is where you’ll insert the brake adjustment tool (or screwdriver). This slot may be covered by a rubber plug; if so, remove the plug. On some brakes, you may need to remove a wheel cylinder access plug in the backing plate.
- Adjust the Brake Shoes: Insert the brake adjustment tool into the slot and locate the star wheel adjuster. This adjuster expands or contracts the brake shoes. Using the tool, turn the star wheel in the tightening direction (usually upward if viewed from below the axle) until the brake shoes make firm contact with the drum, preventing the drum from turning by hand. You will hear a grinding sound when the shoes make contact with the drum.
- Back Off the Adjustment: Once the shoes are making firm contact and the drum won’t turn, slowly back off the adjuster. The typical recommendation is to back off the adjuster until the drum spins freely with a slight drag. This usually requires backing off the adjuster 8-12 clicks. This is the most crucial step. Too tight and your brakes will overheat, too loose and you won’t have enough stopping power.
- Test the Drum: Manually spin the brake drum. It should rotate freely with a slight, consistent drag. You should not hear any loud grinding or scraping noises.
- Repeat for All Brakes: Repeat steps 2 through 7 for all the brakes on your trailer.
- Reinstall the Wheel: Carefully reinstall the wheel and tighten the lug nuts to the manufacturer’s specified torque using a torque wrench.
- Lower and Test: Carefully lower the trailer and remove the safety stands. Connect the trailer’s electrical connector.
- Initial Brake Test: In a safe, open area, perform a series of slow-speed stops to test the brakes. Listen for any unusual noises and feel for even braking.
- Fine-Tune (If Necessary): If you notice uneven braking or other issues, repeat the adjustment process on the affected brakes.
Common Mistakes to Avoid
- Over-tightening the brakes: This can lead to overheating, premature wear, and reduced braking effectiveness.
- Not backing off the adjuster enough: If the brakes are too tight, they will drag, causing heat and wear.
- Ignoring uneven braking: Address any imbalance in braking force immediately to prevent accidents.
- Using the wrong tools: Use the correct brake adjustment tool to avoid damaging the adjuster mechanism.
- Skipping the initial test: Always perform a test run after adjusting the brakes to ensure they are working properly.
Troubleshooting Common Issues
- Brakes are too tight and overheating: Back off the adjuster until the drum spins freely with a slight drag.
- Brakes are too loose and provide insufficient stopping power: Tighten the adjuster until the shoes contact the drum, then back off until there is a slight drag.
- Adjuster mechanism is frozen: Apply penetrating oil to the adjuster mechanism and let it soak for a few minutes. Then, gently try to move the adjuster. If it remains stuck, you may need to replace the adjuster.
- Brake shoes are worn out: If the brake shoes are excessively worn, they will not make proper contact with the drum. Replace the brake shoes.
- Grease on the brake shoes: Disassemble the brakes and clean the brake shoes with brake cleaner. The grease seal on the hub will likely need replacement.
Electric Brake Controller Synchronization
After adjusting the brake shoes, synchronize the trailer brakes with the tow vehicle’s brakes. This is typically done using the gain setting on your electric brake controller. Start with a low gain setting and gradually increase it until the trailer brakes engage smoothly and evenly with the tow vehicle’s brakes. Ideally, the trailer should start braking slightly before the tow vehicle to avoid a jarring sensation. Refer to your brake controller’s manual for specific instructions on synchronization.
FAQs About Electric Trailer Brake Shoe Adjustment
Here are 12 frequently asked questions to further clarify the process:
Q1: How often should I adjust my electric trailer brakes?
Regular adjustment is crucial. A good rule of thumb is to adjust them every 3,000 miles or every three months, whichever comes first. More frequent adjustments may be necessary if you frequently tow in harsh conditions or carry heavy loads.
Q2: How do I know if my electric trailer brakes need adjusting?
Signs that your electric trailer brakes need adjustment include: increased stopping distance, uneven braking, a spongy brake pedal, excessive brake noise, and noticeable brake drag.
Q3: Can I adjust my electric trailer brakes myself, or should I take it to a professional?
If you are comfortable working on mechanical systems and have the necessary tools, you can adjust your electric trailer brakes yourself. However, if you are unsure or uncomfortable, it’s best to have a qualified mechanic do the job. Improper adjustment can be dangerous.
Q4: What is the difference between forward and reverse adjustment on electric trailer brakes?
Most electric trailer brakes are self-adjusting in the forward direction. This means that the brakes automatically adjust when you apply them while moving forward. Manual adjustment, as described in this guide, is still necessary to fine-tune the brakes and ensure they are properly set. Reverse adjustment is typically not required.
Q5: What happens if I don’t adjust my electric trailer brakes?
Neglecting brake adjustment can lead to reduced braking performance, uneven braking, premature brake wear, increased fuel consumption, and an increased risk of accidents.
Q6: What is the star wheel adjuster, and how does it work?
The star wheel adjuster is a mechanism that allows you to manually adjust the position of the brake shoes. It consists of a threaded wheel with teeth (the “star”) that expands or contracts the shoes when turned. Turning the wheel in one direction pushes the shoes outwards towards the drum, while turning it in the opposite direction retracts them.
Q7: How do I know which way to turn the star wheel adjuster to tighten the brakes?
Typically, you want to turn the star wheel adjuster upward if viewing from below the axle, which will expand the brake shoes. However, it’s best to refer to your trailer’s service manual or to experiment carefully, paying attention to the movement of the shoes.
Q8: Can I use WD-40 to loosen a frozen brake adjuster?
While WD-40 is a penetrating lubricant, it’s not the best choice for a frozen brake adjuster. Use a dedicated penetrating oil designed for loosening rusted or corroded parts. Let it soak for a while before attempting to move the adjuster.
Q9: What is the proper torque for lug nuts on a trailer wheel?
The proper torque for lug nuts varies depending on the size and type of lug nuts and the trailer’s specifications. Consult your trailer’s owner’s manual or the wheel manufacturer’s recommendations for the correct torque value. Over-tightening or under-tightening lug nuts can be dangerous.
Q10: What is the purpose of the magnet in electric trailer brakes?
The magnet in an electric trailer brake system is responsible for activating the brakes. When the brake controller sends an electrical signal, the magnet is energized and attracts to the armature surface inside the brake drum. This creates a force that pushes the brake lever, applying the brakes.
Q11: Can I use different types of brake shoes on my trailer?
It’s crucial to use brake shoes that are specifically designed for your trailer’s brake system. Using the wrong type of brake shoes can result in poor braking performance and potential damage to the brake drums.
Q12: Where can I find a diagram of my electric trailer brake system?
You can often find a diagram of your electric trailer brake system in your trailer’s owner’s manual or on the website of the brake manufacturer. You can also search online for diagrams specific to your trailer’s make and model.
By following this guide and the answers to these frequently asked questions, you can confidently adjust your electric trailer brake shoes and ensure safe and reliable towing. Remember, proper brake maintenance is essential for the safety of yourself and others on the road.