The correct adjustment of trailer drum brakes is crucial for safe towing, ensuring optimal stopping power and preventing premature wear. Effectively adjusting drum brakes involves understanding the system, using the proper tools, and following a step-by-step procedure to achieve proper shoe-to-drum contact, leading to confident and controlled braking performance.
Understanding Trailer Drum Brake Systems
Trailer drum brakes operate on a principle similar to those found on older cars and trucks. When the brake pedal is pressed in the tow vehicle, hydraulic pressure (or in some cases, an electric signal) is sent to the trailer’s brake actuator. This actuator then forces the brake shoes against the inside of the brake drum, creating friction that slows the trailer’s wheels. Over time, the brake shoes wear down, creating a gap between the shoes and the drum. This gap reduces braking effectiveness and can lead to a spongy brake pedal feel. Adjusting the brakes compensates for this wear, restoring proper contact and braking performance. The automatic adjusters on many modern trailers can sometimes fail, necessitating manual intervention.
Tools Required for Drum Brake Adjustment
Before you begin, gather the necessary tools:
- Jack and Jack Stands: Essential for safely lifting and supporting the trailer.
- Wheel Chocks: To prevent the trailer from rolling during the adjustment process.
- Brake Adjustment Tool (Spoon): This specialized tool is designed to manipulate the adjuster wheel inside the brake assembly.
- Screwdriver: May be needed to remove access plugs or for minor adjustments.
- Gloves: To protect your hands from dirt and grime.
- Safety Glasses: To protect your eyes.
- Penetrating Oil: Useful for loosening stuck adjuster wheels.
- Torque Wrench: To properly tighten the lug nuts after the adjustment.
- Lug Wrench: To remove the lug nuts.
Step-by-Step Drum Brake Adjustment Procedure
- Safety First: Park the trailer on a level surface. Engage the parking brake of your tow vehicle and chock the wheels of the trailer.
- Raise and Secure: Use a jack to raise the trailer axle, lifting the wheel you’ll be working on off the ground. Securely support the trailer with jack stands. Never work under a trailer supported only by a jack.
- Locate the Adjustment Slot: On the backing plate behind the brake drum, you’ll find an oval or rectangular slot. This is where you’ll insert the brake adjustment tool. There may be a rubber or plastic plug covering the slot, which you’ll need to remove.
- Insert the Adjustment Tool: Insert the brake adjustment tool into the slot. You may need to use a flashlight to see the adjuster wheel inside. The adjuster wheel is a small, toothed wheel that controls the spread between the brake shoes.
- Tighten the Brakes: Using the adjustment tool, turn the adjuster wheel upwards (or downwards, depending on the specific adjuster mechanism – usually upwards) to expand the brake shoes. Listen carefully. You should hear a clicking sound as the adjuster wheel turns. Continue adjusting until the brake shoes make solid contact with the drum, and the wheel becomes difficult to turn by hand. The wheel should turn with noticeable drag.
- Loosen the Brakes: Now, back off the adjuster wheel by turning it in the opposite direction (downwards, if you initially turned it upwards) until the wheel spins freely with a slight, consistent drag. Ideally, the wheel should turn about one full rotation with moderate effort.
- Repeat for Other Wheels: Repeat steps 2-6 for each wheel on the trailer. Ensure consistent adjustment across all brakes for balanced braking.
- Reinstall Wheels and Torque Lug Nuts: Carefully lower the trailer and remove the jack stands. Reinstall the wheels and tighten the lug nuts to the manufacturer’s specified torque using a torque wrench. An improperly torqued wheel is dangerous and can lead to wheel separation.
- Test the Brakes: Before hitting the road, perform a brake test in a safe, controlled environment. Start at a slow speed and gradually increase your speed while applying the brakes. Pay attention to how the trailer tracks. It should stop smoothly and evenly, without pulling to one side or the other. If you notice any unusual noises or pulling, re-inspect and re-adjust the brakes as necessary.
The Importance of Regular Inspection and Maintenance
Regular inspection and maintenance of your trailer’s brakes are critical for safety and longevity. Inspect the brake drums, shoes, and hardware for wear or damage. Replace any worn or damaged parts promptly. It’s also a good idea to re-adjust the brakes after the first few uses of a new or rebuilt trailer as the shoes “seat” into the drums.
Troubleshooting Common Brake Adjustment Problems
- Stuck Adjuster Wheel: If the adjuster wheel is stuck, try applying penetrating oil to the area and let it soak for a few minutes. You may also need to gently tap the backing plate near the adjuster slot with a hammer to help loosen the mechanism.
- Brake Drag: Excessive brake drag can indicate that the brakes are adjusted too tightly. Loosen the adjuster wheel slightly until the wheel spins freely with a slight, consistent drag.
- Uneven Braking: Uneven braking can be caused by uneven adjustment, worn brake shoes, or contaminated brake drums. Inspect and adjust each brake carefully, and replace any worn or contaminated parts.
Frequently Asked Questions (FAQs) About Trailer Drum Brake Adjustment
FAQ 1: How often should I adjust my trailer drum brakes?
You should inspect and adjust your trailer drum brakes at least once a year, or more frequently if you tow regularly or in demanding conditions. Also, adjust after any significant brake work or when you notice a change in braking performance.
FAQ 2: Can I adjust my trailer brakes myself, or do I need a professional?
If you are comfortable working on mechanical systems and have the necessary tools, you can adjust your trailer brakes yourself. However, if you are unsure or uncomfortable, it is always best to have a qualified technician perform the adjustment.
FAQ 3: How do I know if my trailer brakes need adjusting?
Several signs indicate that your trailer brakes need adjusting, including:
- A spongy or low brake pedal feel.
- Reduced braking performance.
- The trailer pulling to one side when braking.
- Excessive brake drum heat.
- An audible clicking sound when braking.
FAQ 4: What happens if I don’t adjust my trailer brakes?
Failing to adjust your trailer brakes can lead to several problems, including:
- Reduced braking performance, increasing stopping distances.
- Premature wear of brake shoes and drums.
- Uneven braking, causing the trailer to pull to one side.
- Overheating of the brakes, leading to brake fade and potential failure.
FAQ 5: Are all trailer drum brakes adjusted the same way?
While the basic principle is the same, there can be slight variations in the adjuster mechanism depending on the manufacturer. Always consult your trailer’s owner’s manual for specific instructions.
FAQ 6: What is the difference between manual and automatic adjusting trailer brakes?
Manual adjusting brakes require periodic adjustment using a brake adjustment tool, as described in this article. Automatic adjusting brakes are designed to self-adjust during braking. However, these automatic adjusters can fail, requiring manual intervention.
FAQ 7: Can I convert manual adjusting brakes to automatic adjusting brakes?
Yes, it is possible to convert manual adjusting brakes to automatic adjusting brakes, but it typically involves replacing the entire brake assembly, including the shoes, hardware, and adjuster mechanism. Consult with a qualified technician to determine if this is the best option for your trailer.
FAQ 8: What is the proper amount of drag I should feel after adjusting the brakes?
The ideal amount of drag is slight and consistent. The wheel should turn freely with noticeable resistance, completing approximately one full rotation with moderate effort. Too much drag can cause overheating, while too little drag indicates insufficient braking power.
FAQ 9: What should I do if I strip the adjuster wheel?
If you strip the adjuster wheel, you will need to replace the entire brake assembly. Attempting to repair the wheel is generally not recommended.
FAQ 10: Can I use a socket or wrench instead of a brake adjustment tool?
While technically possible in some cases, using a socket or wrench is not recommended. A brake adjustment tool is specifically designed to engage the adjuster wheel properly and prevent damage.
FAQ 11: How do I know if my brake drums are too worn to be adjusted?
If the brake drums are significantly worn, cracked, scored, or out of round, they should be replaced. A qualified technician can measure the drum’s thickness to determine if it is within the manufacturer’s specifications.
FAQ 12: What type of grease should I use on the brake adjuster mechanism?
It is generally not necessary to grease the brake adjuster mechanism. Applying grease can attract dirt and debris, which can actually hinder its operation. However, if you do choose to lubricate the mechanism, use a high-temperature brake grease sparingly.
By understanding the principles of trailer drum brake adjustment and following these steps, you can ensure the safety and reliability of your trailer and enjoy confident towing experiences. Remember to prioritize safety and seek professional assistance when needed.