Self-adjusting electric trailer brakes require minimal manual intervention, but ensuring they are properly functioning is crucial for safe towing. Understanding the signs of improper adjustment and knowing how to troubleshoot common issues can prevent accidents and maintain the longevity of your braking system.
Understanding Self-Adjusting Brakes
The Illusion of “Self-Adjusting”
Let’s be clear: while marketed as “self-adjusting,” these brakes aren’t truly maintenance-free. They automatically adjust the brake shoe clearance as they are used, compensating for wear. However, this adjustment mechanism requires regular engagement to function correctly. Infrequent use, rust, or worn components can prevent the self-adjuster from operating as intended, necessitating a manual check and potential adjustment.
The core principle behind self-adjusting brakes is the star wheel adjuster. This small, toothed wheel sits between the brake shoes inside the brake drum. During braking, a lever connected to the actuator arm engages the star wheel, incrementally tightening the brake shoes against the drum to compensate for wear.
Recognizing the Need for Adjustment
Several symptoms indicate that your self-adjusting brakes might require attention:
- Longer Stopping Distance: If your trailer takes significantly longer to stop than usual, the brakes may be out of adjustment.
- Uneven Braking: If the trailer pulls to one side during braking, one or more brakes might be malfunctioning or improperly adjusted.
- Excessive Pedal Travel: A “soft” brake pedal in your tow vehicle could indicate a problem with the trailer brakes, including improper adjustment.
- Unusual Noises: Grinding or squealing sounds from the brakes can signal excessive wear or improper adjustment.
- Weak Braking Performance: A general feeling of weak or unresponsive trailer brakes warrants a thorough inspection.
The Myth of Automatic Perfection: When to Intervene
Don’t rely solely on the self-adjusting mechanism. Regular inspection and manual adjustment are vital for maintaining optimal braking performance. Aim to inspect your brakes at least annually, or more frequently if you tow regularly or in harsh conditions.
Inspection and Manual Adjustment Procedure
While the goal is to let the self-adjusters do their job, sometimes they need a little help or confirmation. Here’s a step-by-step guide:
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Safety First: Park your trailer on a level surface, chock the wheels, and disconnect the electrical connection to the tow vehicle. Wear safety glasses and gloves.
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Access the Adjuster: Locate the adjustment slot on the backing plate, usually covered by a rubber plug. Remove the plug.
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Identify the Star Wheel: Use a brake adjusting tool or a screwdriver with a bent tip to locate the star wheel inside the slot. The direction to turn the star wheel depends on the brake assembly’s orientation. You’ll either be moving the handle up or down to tighten the brakes.
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Tighten the Brakes: Turn the star wheel to expand the brake shoes until they make contact with the brake drum. You should feel resistance when turning the wheel. Don’t over-tighten.
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Back Off the Adjustment: Use the adjusting tool to back off the star wheel until the wheel turns freely and you can spin the tire by hand. Then, tighten the wheel up until there is a slight drag on the tire. The goal is to have the minimum amount of drag on the tire. This is crucial.
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Test the Brakes: Reconnect the electrical connection and perform a slow-speed test to ensure the brakes engage smoothly and evenly. If the brakes feel uneven or grab excessively, repeat the adjustment process.
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Re-Install the Plug: Ensure the adjustment slot plug is securely in place to prevent dirt and moisture from entering.
Diagnosing Common Issues
Sometimes, adjustment alone isn’t enough. If you’re still experiencing braking problems after adjusting the brakes, you might have underlying issues that need to be addressed.
Identifying Root Causes
- Worn Brake Shoes: Brake shoes wear down over time, reducing their effectiveness. Inspect the shoes for excessive wear or damage and replace them if necessary.
- Grease Contamination: Grease or oil on the brake shoes can significantly reduce braking performance. Inspect the brake shoes and drums for contamination and clean or replace them as needed.
- Corroded Components: Rust and corrosion can seize the adjuster mechanism, preventing it from functioning properly. Clean and lubricate the adjuster mechanism or replace it if it’s severely corroded.
- Damaged Magnets: The electric magnets are responsible for activating the brakes. If the magnets are worn or damaged, they won’t provide sufficient braking force. Test the magnets for continuity and replace them if necessary.
- Faulty Wiring: Check the wiring connections to the brakes for corrosion or damage. Ensure that all connections are clean and secure.
Troubleshooting FAQs
Here are answers to some frequently asked questions about self-adjusting electric trailer brakes.
FAQ 1: How often should I adjust my self-adjusting electric trailer brakes?
Answer: While they’re designed to self-adjust, a visual inspection and test run should be performed at least annually or every 12,000 miles, whichever comes first. More frequent checks are recommended for heavy use or towing in demanding conditions.
FAQ 2: Can I adjust self-adjusting brakes while the trailer is loaded?
Answer: It’s best to adjust brakes with the trailer unloaded. A loaded trailer can affect the suspension and braking dynamics, potentially leading to an inaccurate adjustment.
FAQ 3: What tools do I need to adjust self-adjusting electric trailer brakes?
Answer: You’ll need a jack, jack stands, wheel chocks, a brake adjusting tool (or a screwdriver with a bent tip), a rubber mallet, safety glasses, gloves, and potentially a multimeter for electrical testing.
FAQ 4: How do I know if the self-adjuster is working correctly?
Answer: A properly functioning self-adjuster will maintain a consistent brake shoe clearance. If you notice a gradual decrease in braking performance over time, the self-adjuster might not be working effectively. Listen for a clicking sound from the brakes while applying and releasing the brake pedal; this indicates the adjuster is engaging.
FAQ 5: What if the star wheel is stuck and I can’t turn it?
Answer: Apply penetrating oil to the star wheel adjuster and let it soak for a few hours. Then, gently tap the backing plate with a rubber mallet to help loosen the adjuster. If it remains stuck, you may need to disassemble the brake assembly for a thorough cleaning and lubrication or replacement of the adjuster.
FAQ 6: Can I use a regular screwdriver instead of a brake adjusting tool?
Answer: While a regular screwdriver can be used, a brake adjusting tool is designed specifically for this task and offers better leverage and control. A screwdriver with a bent tip is a suitable alternative. Avoid using a sharp screwdriver, as it can damage the star wheel.
FAQ 7: What does “backing off” the brakes mean?
Answer: “Backing off” the brakes refers to loosening the adjustment of the brake shoes to allow the wheel to spin freely. After tightening the brakes during adjustment, you need to back them off slightly to prevent the brakes from dragging and overheating.
FAQ 8: How do I check the brake magnets for proper function?
Answer: Use a multimeter to check the resistance of the brake magnets. A typical resistance reading is between 3 and 4 ohms. If the resistance is significantly higher or lower, or if there’s no continuity, the magnet is likely faulty and needs to be replaced.
FAQ 9: What happens if I over-tighten the brakes?
Answer: Over-tightening the brakes will cause them to drag, leading to excessive heat buildup, premature brake shoe wear, and reduced fuel economy. It can also damage the brake drums.
FAQ 10: Can I adjust my trailer brakes while they are wet?
Answer: It’s best to adjust trailer brakes when they are dry. Water can affect the adjustment process and potentially lead to inaccurate results. If the brakes are wet, allow them to dry thoroughly before adjusting them.
FAQ 11: My trailer brakes work fine sometimes, and other times they don’t. What could be the problem?
Answer: This intermittent issue could be caused by several factors, including corroded wiring connections, a faulty brake controller, or worn brake magnets. Thoroughly inspect the entire braking system, including the wiring, controller, and brake components, to identify the root cause.
FAQ 12: Should I adjust all the brakes on my trailer, or just the ones that seem to be causing problems?
Answer: It’s always best to adjust all the brakes on your trailer to ensure even braking performance. Adjusting only the problematic brakes can lead to uneven braking forces and potential safety hazards.