Replacing trailer wheel bearings, while seemingly daunting, is a crucial preventative maintenance task that ensures safe and reliable towing. This guide provides a step-by-step approach, empowering you to perform this essential procedure and avoid costly breakdowns on the road.
Why Replace Trailer Wheel Bearings?
Trailer wheel bearings are the unsung heroes of smooth and safe towing, facilitating the free rotation of your trailer wheels. Over time, these bearings are subjected to constant friction, heat, and contamination, leading to wear and eventual failure. Neglecting their maintenance can result in catastrophic consequences, including wheel bearing failure, wheel separation, and potentially dangerous accidents. Regular replacement is vital for maintaining optimal performance and ensuring your safety and the safety of others.
Identifying the Need for Replacement
Knowing when to replace your trailer wheel bearings can save you from roadside emergencies. Here are key indicators that signal it’s time for a change:
- Excessive Wheel Wobble: If you notice your trailer wheel(s) wobbling during towing, it’s a strong indication of worn or damaged bearings.
- Unusual Noises: Grinding, clicking, or popping sounds emanating from the wheel hubs are telltale signs of bearing issues.
- Overheating Hub: After a period of towing, carefully touch the wheel hubs. An excessively hot hub suggests excessive friction and potential bearing failure.
- Grease Leakage: Leaking grease from the rear of the hub indicates a seal failure, which compromises bearing lubrication and accelerates wear.
- Regular Maintenance Schedule: Even without obvious symptoms, it’s recommended to replace trailer wheel bearings every 12,000 miles or annually, whichever comes first, particularly if you frequently tow in harsh conditions.
Tools and Materials You’ll Need
Before you begin the replacement process, gather the following tools and materials:
- Jack and Jack Stands: Essential for safely lifting and supporting the trailer.
- Wheel Chocks: To secure the trailer and prevent accidental movement.
- Socket Set and Wrenches: Including sockets and wrenches of the appropriate sizes for your trailer’s axle and hub components.
- Hammer or Mallet: For gently tapping components into place.
- Bearing Packer: To efficiently and thoroughly pack new bearings with grease.
- Grease Gun: For lubricating the bearings and hub.
- New Wheel Bearings and Seals: Ensure you purchase the correct size and type for your trailer. Matching part numbers is recommended.
- Grease: Specifically formulated for wheel bearings. Marine-grade grease is preferable for boat trailers.
- Brake Cleaner: For cleaning the hub and spindle.
- Rags or Paper Towels: For wiping away excess grease and cleaning components.
- Gloves: To protect your hands.
- Safety Glasses: To protect your eyes from debris.
- Torque Wrench: For tightening the axle nut to the manufacturer’s specified torque.
- Optional: Bearing Race and Seal Driver Kit: Makes removing and installing races and seals easier and prevents damage.
Step-by-Step Replacement Procedure
This procedure outlines the general steps for replacing trailer wheel bearings. Always consult your trailer’s manual for specific instructions and torque specifications.
1. Preparation
- Park the trailer on a level surface and engage the parking brake.
- Chock the wheels opposite the side you’ll be working on.
- Loosen the lug nuts on the wheel you’ll be removing, but don’t remove them completely yet.
2. Lifting and Supporting the Trailer
- Use a jack to lift the trailer until the tire is off the ground.
- Place a jack stand under the axle for safety. Never work under a trailer supported only by a jack.
- Remove the lug nuts and the wheel.
3. Removing the Hub Assembly
- Remove the dust cap from the hub using a screwdriver or pliers.
- Straighten the cotter pin, if present, and remove it from the axle nut.
- Remove the axle nut.
- Carefully pull the hub assembly off the spindle. The outer bearing will likely come out with the hub.
4. Removing the Old Bearings and Seals
- Use a punch and hammer (or a bearing race driver tool) to drive out the old bearing races from the hub. Work evenly around the race to avoid damaging the hub.
- Pry out the old grease seal from the rear of the hub.
- Remove the inner bearing.
5. Cleaning and Inspecting Components
- Thoroughly clean the hub, spindle, and all other components with brake cleaner.
- Inspect the spindle for any signs of damage, such as scoring or wear. If damaged, the spindle may need to be replaced.
- Inspect the hub for cracks or damage. Replace if necessary.
6. Installing the New Bearing Races
- Use a bearing race driver tool to install the new bearing races into the hub. Ensure they are seated fully and squarely. If you don’t have a race driver, use a brass drift and hammer, tapping carefully and evenly around the race.
- Correctly seating the races is critical. An improperly seated race can lead to premature bearing failure.
7. Packing the New Bearings
- Use a bearing packer to thoroughly pack the new bearings with grease. If you don’t have a bearing packer, you can pack them by hand.
- To pack by hand, place a glob of grease in your palm and press the wide end of the bearing into the grease until the grease oozes out the other side. Rotate the bearing and repeat until it’s completely packed.
8. Installing the New Bearings and Seals
- Install the inner bearing into the hub.
- Install the new grease seal using a seal driver or a piece of wood and a hammer. Drive the seal in until it’s flush with the hub.
- Carefully slide the hub assembly onto the spindle.
- Install the outer bearing.
- Install the axle nut.
9. Adjusting the Bearing Preload
- Tighten the axle nut until it’s snug.
- Back off the nut slightly, then tighten it again until it’s just snug.
- Loosen the nut again, then tighten it hand-tight. The hub should spin freely with a slight amount of play.
- Install a new cotter pin (if applicable) to secure the axle nut. If the cotter pin holes don’t line up, slightly tighten or loosen the nut until they do. Never loosen the nut more than necessary to align the holes.
- Install the dust cap.
10. Reinstalling the Wheel
- Mount the wheel and tighten the lug nuts hand-tight.
- Lower the trailer to the ground and remove the jack stand.
- Torque the lug nuts to the manufacturer’s specified torque using a torque wrench.
11. Final Checks
- Spin the wheel to ensure it rotates freely without any binding or unusual noises.
- Recheck the lug nuts after a short distance (e.g., 50 miles) to ensure they remain tight.
FAQs about Trailer Wheel Bearing Replacement
Here are some frequently asked questions about trailer wheel bearing replacement:
1. How often should I repack my trailer wheel bearings?
Repacking your trailer wheel bearings is generally recommended every 12 months or 12,000 miles, whichever comes first. However, if you frequently submerge your trailer in water (especially saltwater), more frequent repacking might be necessary.
2. What type of grease should I use for trailer wheel bearings?
Use a high-quality, water-resistant wheel bearing grease. Marine-grade grease is specifically formulated for boat trailers and provides superior protection against corrosion. Lithium-complex greases are also a good option.
3. Can I reuse my old wheel bearings if they look okay?
It’s generally not recommended to reuse old wheel bearings, even if they appear to be in good condition. They may have microscopic wear or damage that isn’t visible to the naked eye, which could lead to premature failure.
4. What is bearing preload, and why is it important?
Bearing preload refers to the amount of axial force applied to the bearings when the axle nut is tightened. Proper preload is essential for ensuring that the bearings operate smoothly and efficiently. Too much preload can cause excessive friction and heat, while too little preload can lead to bearing wobble and premature wear.
5. What happens if I overtighten the axle nut?
Overtightening the axle nut can damage the bearings and races, leading to premature failure. It can also cause the hub to overheat and potentially seize up.
6. What happens if I don’t tighten the axle nut enough?
Under-tightening the axle nut can cause the bearings to wobble and wear prematurely. It can also cause the hub to come loose from the spindle, which can be extremely dangerous.
7. How do I know if I need to replace the bearing races?
If the bearing races are pitted, scored, or damaged, they should be replaced. Even if the races look okay, it’s often recommended to replace them whenever you replace the bearings.
8. Can I replace trailer wheel bearings myself, or should I take it to a professional?
Replacing trailer wheel bearings is a task that can be done by a mechanically inclined individual with the proper tools and knowledge. However, if you’re not comfortable working on your trailer or if you’re not sure what you’re doing, it’s best to take it to a qualified mechanic.
9. How can I prevent water from getting into my trailer wheel bearings?
Using a good quality marine grease and regularly inspecting and replacing the grease seals can help prevent water from entering your trailer wheel bearings. You can also consider using bearing protectors, which are designed to keep water and contaminants out of the hub.
10. What are bearing buddies, and do I need them?
Bearing buddies are spring-loaded devices that replace the dust cap and maintain a slight positive pressure inside the hub, preventing water and contaminants from entering. They are particularly beneficial for boat trailers that are frequently submerged in water. Whether you need them depends on your towing habits and the type of trailer you have.
11. How much does it cost to replace trailer wheel bearings?
The cost of replacing trailer wheel bearings can vary depending on the type of trailer, the cost of the bearings and seals, and whether you do it yourself or hire a professional. Generally, DIY replacement costs range from $50 to $150 per axle, while professional replacement can cost $200 to $500 per axle.
12. Are there any special considerations for boat trailers?
Yes, boat trailers require special attention due to their frequent exposure to water, especially saltwater. Using marine-grade grease, regularly inspecting and replacing the grease seals, and considering bearing protectors are all important considerations for boat trailers. Flushing the hubs with fresh water after each use can also help to remove salt and contaminants.
By following these steps and taking the necessary precautions, you can successfully replace your trailer wheel bearings and ensure safe and reliable towing for years to come. Remember, preventative maintenance is key to avoiding costly breakdowns and ensuring your safety on the road.