Changing trailer bearings is a crucial maintenance task that prevents catastrophic wheel failure and ensures safe towing. While it might seem daunting, with the right tools and a methodical approach, replacing your trailer bearings is a task any reasonably handy person can accomplish, saving significant costs and potential roadside headaches. This guide provides a step-by-step walkthrough and expert advice to help you confidently tackle this important job.
Understanding the Importance of Trailer Bearings
Trailer bearings are critical components that allow your trailer wheels to rotate smoothly around the axle. They are subjected to constant friction, heat, and stress, making them prone to wear and tear. Neglecting bearing maintenance can lead to bearing failure, resulting in a seized wheel, damage to the axle, and potentially a dangerous accident. Regular inspection and replacement are essential for maintaining a safe and reliable trailer.
When to Change Your Trailer Bearings
Several telltale signs indicate it’s time to replace your trailer bearings:
- Excessive play: Jack up the wheel and try to rock it back and forth. If you feel significant movement or hear a clunking sound, the bearings are likely worn.
- Overheating: After a short trip, carefully touch the hub (avoiding burns!). If it’s significantly hotter than the other hubs, it could indicate bearing problems.
- Grease leakage: Grease leaking from the hub seal is a sign that the seal is failing and may be contaminating the bearings.
- Unusual noises: Grinding, squealing, or rumbling sounds coming from the wheel area while towing are strong indicators of worn or damaged bearings.
- Mileage-based replacement: Even without noticeable symptoms, it’s generally recommended to replace your trailer bearings every 12,000 miles or annually, whichever comes first, especially for trailers used frequently or under heavy loads.
Tools and Materials You’ll Need
Before you begin, gather the necessary tools and materials:
- Jack and jack stands: To safely lift and support the trailer.
- Wheel chocks: To prevent the trailer from rolling.
- Gloves: To protect your hands.
- Safety glasses: To protect your eyes.
- Wrench set: To remove the lug nuts and other hardware.
- Hammer or mallet: To tap out the old bearings and install the new ones.
- Punch or screwdriver: To remove the dust cap.
- Bearing packer: A tool that efficiently packs grease into the bearings (highly recommended).
- New trailer bearings: Ensure you purchase the correct bearing kit for your trailer axle. Check the manufacturer’s specifications.
- New grease seals: Always replace the seals when replacing the bearings.
- High-temperature bearing grease: Use a quality grease specifically designed for trailer bearings.
- Brake cleaner: To clean the hub and axle spindle.
- Shop rags or paper towels: For cleaning.
- Torque wrench: To tighten the axle nut to the manufacturer’s specifications.
- Bearing race and seal driver kit: For proper installation of races and seals (recommended).
Step-by-Step Guide to Changing Trailer Bearings
This section provides a detailed walkthrough of the bearing replacement process.
Step 1: Prepare the Trailer
- Park the trailer on a level surface and chock the wheels to prevent movement.
- Loosen the lug nuts on the wheel you’ll be working on.
- Use a jack to lift the trailer and support it with jack stands placed under the trailer frame, not the axle.
- Remove the wheel.
Step 2: Remove the Hub Assembly
- Use a punch or screwdriver to gently pry off the dust cap from the hub.
- Remove the cotter pin (if present) from the castle nut or axle nut.
- Remove the castle nut or axle nut and the washer behind it.
- Carefully pull the hub assembly straight off the axle spindle. Be mindful of the outer bearing, which may come loose.
Step 3: Remove the Old Bearings and Seals
- Remove the outer bearing (if it didn’t already come loose).
- Flip the hub over and use a punch and hammer to tap out the inner bearing race from inside the hub. Work around the race evenly to avoid damaging the hub.
- Use a seal puller or a screwdriver to pry out the old grease seal from the back of the hub.
Step 4: Clean and Inspect the Hub and Spindle
- Thoroughly clean the hub and axle spindle with brake cleaner to remove all old grease and debris.
- Inspect the spindle for any signs of damage, such as scoring, pitting, or bending. If the spindle is damaged, it may need to be repaired or replaced.
- Inspect the inside of the hub where the bearing races sit for any damage or wear.
Step 5: Install the New Bearing Races
- Use a bearing race and seal driver kit to install the new bearing races into the hub. Ensure the races are seated fully and evenly. If you don’t have a driver kit, you can carefully use a hammer and a block of wood to tap them in, being extremely careful not to damage the races.
Step 6: Pack the New Bearings with Grease
- Thoroughly pack the new bearings with high-temperature bearing grease using a bearing packer or by hand. If packing by hand, force the grease into the bearing from the wider end until it comes out the other side, ensuring every roller is coated.
Step 7: Install the Inner Bearing and Grease Seal
- Place the greased inner bearing into the hub.
- Use a seal driver to install the new grease seal into the back of the hub. Make sure the seal is seated properly and flush with the hub.
Step 8: Install the Hub Assembly
- Carefully slide the hub assembly onto the axle spindle.
- Place the greased outer bearing into the hub.
- Install the washer and castle nut or axle nut.
Step 9: Adjust the Bearing Preload
- Tighten the castle nut or axle nut until snug.
- Back off the nut until it’s just loose.
- Tighten the nut by hand until it’s snug again.
- If using a castle nut, align the castle nut slots with the hole in the spindle and install a new cotter pin. If using an axle nut, torque it to the manufacturer’s specifications using a torque wrench. Proper torque is crucial for bearing life.
- Ensure the hub spins freely but without excessive play.
Step 10: Replace the Dust Cap and Wheel
- Tap the dust cap back onto the hub.
- Install the wheel and tighten the lug nuts in a star pattern to the manufacturer’s specifications.
- Remove the jack stands and lower the trailer.
- Double-check the lug nuts after a short trip.
Frequently Asked Questions (FAQs)
1. How often should I repack my trailer bearings?
Generally, it’s recommended to repack your trailer bearings every 12 months or 12,000 miles, whichever comes first. More frequent repacking may be necessary for trailers used in harsh conditions or under heavy loads.
2. What type of grease should I use for trailer bearings?
Use a high-temperature, lithium-based or synthetic grease specifically designed for trailer bearings. These greases are formulated to withstand the high temperatures and pressures generated in trailer wheel bearings.
3. What happens if I don’t change my trailer bearings?
Neglecting bearing maintenance can lead to bearing failure, resulting in a seized wheel, damage to the axle, and potentially a dangerous accident. It can also lead to costly repairs.
4. Can I reuse old trailer bearings?
No, it’s strongly recommended to always replace trailer bearings with new ones. Used bearings have already experienced wear and tear, and reusing them can compromise their performance and lifespan.
5. How do I know what size bearings to buy for my trailer?
Refer to your trailer’s owner’s manual or look for markings on the old bearings. You can also measure the inner diameter, outer diameter, and width of the old bearings and match them to the specifications of the new bearings. Consult with a trailer parts supplier for assistance.
6. What is a bearing buddy, and do I need one?
A bearing buddy is a spring-loaded grease fitting that replaces the dust cap and helps maintain pressure inside the hub, preventing water and contaminants from entering the bearings. While they can be helpful, they don’t eliminate the need for regular bearing maintenance. Overgreasing a bearing buddy can also damage the rear seal.
7. What is the correct bearing preload?
The correct bearing preload is crucial for bearing life. The goal is to have the bearings snug but not too tight. The hub should spin freely without excessive play. Refer to your trailer’s owner’s manual for specific torque specifications.
8. What is the difference between a bearing race and a bearing?
The bearing race is the hardened steel cup that the bearing rollers roll against. The bearing is the assembly of rollers and cage that sit inside the race. Both need to be replaced simultaneously.
9. What does “packing” bearings mean?
“Packing” bearings refers to the process of forcing grease into the bearing to ensure all rollers and internal surfaces are thoroughly lubricated. This prevents metal-to-metal contact and reduces friction.
10. Can I change trailer bearings myself, or should I take it to a professional?
Changing trailer bearings is a task any reasonably handy person can accomplish with the right tools and a methodical approach. However, if you’re uncomfortable working on mechanical systems, it’s best to take your trailer to a qualified mechanic.
11. What if I damage the spindle while removing the old bearings?
If the spindle is severely damaged, it may need to be repaired or replaced. Minor damage, such as light scoring, can sometimes be smoothed out with emery cloth. Consult with a trailer repair specialist for advice.
12. How can I prevent my trailer bearings from failing prematurely?
- Regularly inspect your bearings for signs of wear.
- Repack your bearings at the recommended intervals.
- Use high-quality grease.
- Avoid overloading your trailer.
- Avoid driving through deep water whenever possible.
- Properly adjust the bearing preload during installation.
- Use a bearing buddy appropriately.
By following these steps and recommendations, you can confidently change your trailer bearings and ensure safe and reliable towing for years to come. Remember, prevention is always better than cure when it comes to trailer maintenance.