Adjusting the springs on an enclosed trailer is crucial for ensuring a smooth, safe, and efficient towing experience. By understanding the principles behind trailer spring systems and following a systematic approach, you can fine-tune your trailer’s ride height, load capacity, and overall stability.
Understanding Trailer Spring Systems
Enclosed trailers rely on spring systems to absorb shocks, distribute weight evenly, and maintain proper ride height. These systems typically consist of leaf springs, but torsion axles and other variations also exist. Proper adjustment is critical because an overloaded or imbalanced trailer can lead to swaying, tire wear, and even accidents. Incorrect spring tension can also cause damage to the trailer frame and cargo.
Types of Trailer Spring Systems
- Leaf Springs: The most common type, consisting of curved steel leaves stacked together. They provide a simple and robust suspension.
- Torsion Axles: Utilize a rubber cord or internal metal rod encased in a metal tube to provide suspension. They offer a smoother ride and require less maintenance than leaf springs.
- Coil Springs: Less common in enclosed trailers, but sometimes used in conjunction with other systems for improved shock absorption.
Indicators of Spring Adjustment Needs
Several signs indicate that your enclosed trailer springs may need adjustment:
- Uneven Tire Wear: One tire wearing faster than the others suggests an imbalanced load or misaligned axles, potentially caused by spring issues.
- Sagging Trailer: If the trailer sits lower on one side or in the rear when loaded, the springs may be fatigued or improperly adjusted.
- Excessive Bouncing: Bouncing or swaying during towing indicates insufficient spring damping.
- Difficulty Maintaining Level Ride: Struggle to keep the trailer level when loaded suggests insufficient spring capacity.
Adjusting Leaf Springs: A Step-by-Step Guide
Adjusting leaf springs primarily involves ensuring equal tension on both sides of the trailer and adding or removing leaves to modify the spring rate. Before making any adjustments, always consult your trailer’s owner’s manual for specific recommendations and safety precautions.
Safety First: Preparation and Precautions
- Level Surface: Ensure the trailer is parked on a perfectly level surface.
- Wheel Chocks: Secure the wheels with chocks to prevent movement.
- Jack Stands: Use properly rated jack stands to support the trailer frame securely. Never work under a trailer supported only by a jack.
- Safety Glasses and Gloves: Protect your eyes and hands from debris and potential injuries.
- Consult the Manual: Refer to your trailer’s owner’s manual for torque specifications and specific instructions.
Step 1: Assessment and Inspection
- Measure Ride Height: Measure the distance from the ground to the trailer frame at several points to identify discrepancies.
- Inspect Springs: Visually inspect the leaf springs for signs of damage, rust, or broken leaves. Replace any damaged springs.
- Check U-Bolts: Ensure U-bolts securing the axle to the springs are properly tightened to the manufacturer’s specifications. Loosen or tighten as needed.
- Evaluate Load Distribution: Uneven load distribution can mimic spring problems. Ensure the load is centered and balanced within the trailer.
Step 2: Adjusting Spring Tension (Adding or Removing Leaves)
- Adding Leaves (Increasing Spring Rate): If the trailer sags excessively when loaded, consider adding leaf springs. This will increase the trailer’s load-carrying capacity. Purchase leaf springs that match your trailer’s specifications. Typically, this involves removing the U-bolts, lifting the axle slightly, and inserting the additional leaf spring into the existing stack.
- Removing Leaves (Decreasing Spring Rate): Removing a leaf spring can soften the ride, but it also reduces the trailer’s load capacity. Only remove leaves if your trailer is consistently carrying lighter loads than its maximum capacity allows. Ensure you remove leaves equally from both sides.
- Shimming: In some cases, shims can be used to slightly adjust the angle of the axle relative to the frame, which can impact ride height and handling. However, this should be done carefully and with professional guidance if you’re unsure.
Step 3: Reassembly and Torqueing
- Reassemble Spring Pack: Carefully reassemble the spring pack, ensuring all leaves are aligned.
- Install U-Bolts: Install new U-bolts (recommended) and tighten them to the manufacturer’s specified torque. Tighten in a criss-cross pattern to ensure even pressure.
- Lower Trailer: Slowly lower the trailer onto the wheels.
- Re-Measure Ride Height: Re-measure the ride height to ensure it is even on both sides.
Adjusting Torsion Axles: A More Complex Task
Adjusting torsion axles is generally more complex and often requires specialized tools and expertise. Unless you are experienced and have the proper equipment, it is best to consult a qualified trailer mechanic.
Addressing Torsion Axle Issues
- Ride Height Adjustment: Some torsion axles have adjustable ride height settings. Refer to the axle manufacturer’s instructions.
- Axle Replacement: If a torsion axle has sagged significantly or is damaged, it may need to be replaced entirely.
- Rubber Cord Deterioration: Over time, the rubber cord inside a torsion axle can deteriorate, leading to reduced suspension performance. This often necessitates axle replacement.
Post-Adjustment Checks and Maintenance
After adjusting the springs, perform the following checks:
- Test Tow: Take the trailer for a short test tow to evaluate its handling and ride quality.
- Monitor Tire Wear: Regularly monitor tire wear to ensure it remains even.
- Periodic Inspection: Periodically inspect the springs, U-bolts, and other suspension components for signs of wear or damage.
- Lubrication: Lubricate spring components, such as leaf spring bushings, to prevent friction and extend their lifespan.
Frequently Asked Questions (FAQs)
Here are some frequently asked questions about adjusting trailer springs:
FAQ 1: How do I know what weight capacity springs I need?
Consult your trailer’s VIN plate or manufacturer’s specifications to determine the Gross Vehicle Weight Rating (GVWR). This rating indicates the maximum permissible weight of the trailer, including cargo. Choose springs with a combined weight capacity that meets or exceeds the GVWR.
FAQ 2: Can I just add air bags to my leaf springs?
Yes, adding air bags can supplement leaf springs and provide adjustable load support. This is a common solution for trailers that occasionally carry heavier loads. However, air bags should be installed and used according to the manufacturer’s instructions.
FAQ 3: What tools do I need to adjust leaf springs?
You’ll typically need a jack, jack stands, wheel chocks, sockets and wrenches (including a torque wrench), a hammer, penetrating oil, and possibly a pry bar. A digital level can also be helpful for measuring ride height.
FAQ 4: How often should I inspect my trailer springs?
Inspect your trailer springs at least twice a year, especially before and after long trips or periods of heavy use. More frequent inspections may be necessary if you frequently carry heavy loads or tow on rough roads.
FAQ 5: What is the proper torque for U-bolts?
The proper torque for U-bolts varies depending on the bolt size and material. Refer to the U-bolt manufacturer’s specifications or your trailer’s owner’s manual for the correct torque value.
FAQ 6: Can I adjust the springs with the trailer loaded?
No, never adjust the springs with the trailer loaded. The load will make it impossible to accurately assess the spring tension and can create a dangerous situation. Always unload the trailer completely before making any adjustments.
FAQ 7: What is spring sag, and how can I prevent it?
Spring sag is the gradual weakening and flattening of the springs over time. To prevent spring sag, avoid overloading the trailer, distribute the load evenly, and regularly inspect and maintain the springs.
FAQ 8: What is the difference between spring rate and load capacity?
Spring rate refers to the amount of force required to compress the spring a certain distance. Load capacity refers to the maximum weight the spring can support without permanent deformation.
FAQ 9: Can I use different spring rates on each side of the trailer?
No, using different spring rates on each side of the trailer is generally not recommended. This can create an imbalance and affect handling and stability.
FAQ 10: Should I replace all the springs at once?
If one spring is showing signs of significant wear or damage, it’s generally recommended to replace both springs on the same axle simultaneously. This ensures even performance and prevents uneven wear on other suspension components.
FAQ 11: What is the best way to lubricate leaf springs?
Apply a lubricant specifically designed for leaf springs to the areas where the leaves contact each other and the bushings. Avoid using petroleum-based lubricants, as they can attract dirt and grime.
FAQ 12: Where can I find replacement leaf springs for my trailer?
Replacement leaf springs can be found at trailer supply stores, auto parts stores, and online retailers. Be sure to specify the correct length, width, and capacity for your trailer’s springs.