Yes, trailer wheel bearings absolutely need to be regularly greased in order to function properly and avoid damage. Proper lubrication is essential for the bearings to run smoothly and prevent overheating, noise, wear and tear, and potential failure. Trailer bearings support heavy loads while the trailer is in motion, so regular maintenance is critical.
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Why do trailer wheel bearings need grease?
There are a few key reasons why routine greasing is vital for trailer wheel bearings:
- Prevents overheating – The friction in moving bearings generates heat. Grease lubricates the bearings and reduces friction and heat buildup.
- Extends bearing life – Grease protects the bearing surfaces from direct metal-on-metal contact, minimizing wear.
- Prevents corrosion – Seals out water and contaminants that can cause corrosion and deterioration.
- Enables smooth rolling – The lubrication cuts down on noise and resistance for easier towing.
- Provides load support – Grease enables bearings to handle heavy trailer loads without excessive stress.
Grease forms a barrier between the moving parts inside the wheel hub assembly, enabling the bearings to roll freely without overheating from friction. This protection maximizes the functional lifespan of the bearings.
How often should trailer wheel bearings be repacked?
Most manufacturers recommend repacking trailer wheel bearings at least once per year or every 12,000 miles. However, the ideal greasing frequency depends on several factors:
- Usage – Bearings on frequently used trailers need greasing more often.
- Load – Heavier loads put more stress on bearings, necessitating more frequent lubrication.
- Road conditions – Rough roads accelerate wear, so the bearings need grease changes more regularly.
- Climate – Hot temperatures may break down grease faster than cold climates.
- Age – Older trailers typically need more frequent bearing servicing.
Any unusually high heat, noise or resistance when towing can indicate insufficient lubrication and the need for immediate repacking. With routine use, an annual repack is recommended. Increase greasing frequency for heavy trailer use or intensive towing conditions.
How to repack trailer wheel bearings
Repacking trailer wheel bearings is a straightforward process you can do yourself, if you have the proper tools and follow all safety precautions. Here are the basic steps:
- Chock the trailer wheels, raise the end and secure it on adequate jack stands.
- Remove the wheel, brake drum and cotter pin.
- Carefully extract the spindle nut and washer.
- Pull the hub assembly out, being careful not to drop the outer bearing.
- Thoroughly clean all old grease and contaminants from the hub, bearings, races and seals.
- Inspect components for wear or damage. Replace any defective parts.
- Pack the bearings fully with fresh grease.
- Reinstall the inner bearing, grease seal, outer bearing and hub assembly.
- Replace the washer and spindle nut. Tighten just enough to remove any play.
- Reinsert a properly bent cotter pin to lock the spindle nut in place.
- Replace the drum, wheel, and lower the trailer.
- Repeat procedure on the other wheel.
Be sure to use a high quality waterproof wheel bearing grease. Follow your trailer manufacturer’s specifications for the amount and type of grease required. Taking the time to regularly repack the bearings helps prevent costly repairs down the road.
Grease fitting types
There are a few common types of grease fittings used on trailer wheel bearings that allow new grease to be pumped in without removing the entire hub:
- Straight – Most common type. Grease gun nozzle presses straight on.
- Angled – 45 or 90 degree angle for hard to reach fittings.
- Button head – Round, flatten end. Must use special button head grease gun.
- Pressure relief – Has spring-loaded valve to let excess grease flow out.
It’s important to identify the fitting type so you can use the proper grease gun nozzle and connector. Pumping in new grease every 3-6 months can extend the time between full repacks.
Grease quality
Choosing a high performance grease is critical for optimal trailer wheel bearing protection and longevity. Here’s what to look for in a quality grease:
- Lithium-complex formula – Offers strength for heavy loads plus water resistance.
- NLGI GC-LB certification – Meets stringent performance standards for wheel bearing lubrication.
- EPO fortification – Enhanced with antioxidants to prevent grease deterioration.
- Corrosion inhibitors – Chemically neutralizes rust-causing moisture.
- High dropping point – Won’t melt and run out from frictional heat.
Always consult your owner’s manual for the exact grease specifications. Using a high-quality, water-resistant wheel bearing grease can significantly extend the maintenance intervals.
Signs bearings need grease
Pay attention while towing your trailer and watch for these signs that the wheel bearings need immediate lubrication:
- High heat around the hubs
- A burning smell from hot bearings
- Visible grease leakage
- Excessive noise when towing
- Wheel wobble or shimmy
- Rough rotation when spinning the wheel
- Visible rust or corrosion around bearings
Any of these symptoms mean the bearings are under stress from friction and lack of grease. Continuing to tow with insufficient lubrication can quickly lead to severe bearing damage or failure.
Bearing wear limits
Even with routine greasing, trailer wheel bearings over time suffer wear and must be replaced once reaching these limits:
| Part | Maximum Wear Limit |
|---|---|
| Bearing races | .002″ groove depth |
| Bearing balls/rollers | .002″ flat spots |
| Bearing rollers | .010″ shorter than new |
Measure and inspect components at each repack. Replace bearings exceeding wear limits to avoid failure. Both inner and outer bearings should be replaced simultaneously in a wheel hub set.
Bearing replacement
While routine greasing can maximize their lifespan, trailer wheel bearings will eventually need replacement. Here are some tips for this repair job:
- Always replace bearings in full sets – both inner and outer races with rollers.
- Check the bearing housing bores for wear or damage. Repair as needed.
- Clean all parts thoroughly including seals, spacers, grease caps.
- Only use a bearing press for installation to avoid damage.
- Tighten the spindle nut correctly – not too loose or tight.
- Insert new cotter pin to lock nut after adjusting play.
- Check for proper free rotation when done.
With quality parts and careful installation, new wheel bearings should achieve thousands of miles of reliable service. Be sure to grease the new bearings properly at the recommended intervals.
Conclusion
Regularly repacking trailer wheel bearings with fresh grease is absolutely critical to avoid premature failure. Grease lubricates the bearings, reduces wear, and protects them from corrosion. Most trailers need annual bearing repacking, but increase frequency for heavy use. Always watch for signs of insufficient grease while towing and be prepared to replace worn bearings. Properly greased bearings lead to smooth, trouble-free trailer operation for the long run.