What happens if you don’t repack trailer bearings?

Properly maintaining trailer wheel bearings is critical to avoid breakdowns and accidents when towing a trailer. Repacking the bearings at regular intervals is an essential part of that maintenance. But what actually happens if you neglect this important task?

How Do Trailer Bearings Work?

Trailer wheel bearings allow the wheels to spin freely around the axle. They are packed with grease which lubricates and protects the bearings from wear and overheating. As the wheel turns, the inner and outer bearings rotate against each other, held in place by the bearing races in the hub. The grease fills the spaces between the ball bearings, keeping them separated and reducing friction and heat buildup.

Trailer wheel bearings are sealed to keep dirt and water out of the hub. But they are not 100% sealed, so some moisture and contaminants will still seep in over time. The grease also gradually breaks down through normal use. That’s why periodic repacking is necessary to replenish the grease and maintain proper lubrication.

What Happens When Bearings Are Not Repacked?

If bearings are not repacked per the manufacturer’s recommendations, normally every 12,000 miles or 12 months, a number of problems can occur:

• Grease breaks down – Over time, the grease oxidizes and loses its lubricating properties. This leads to increased friction and heat.
• Bearings wear faster – With inadequate lubrication, the bearings wear out more quickly.
• Bearings overheat – Friction causes the hub and bearings to get extremely hot, sometimes over 400°F. This can lead to expansion, deformation, and premature failure.
• Seals fail – High heat also causes the seals to fail, allowing contaminants to enter the bearings.
• Bearings seize – With no lubrication, bearings can seize or freeze to the spindle. This will prevent the wheel from turning.
• Excess play develops – Wear and deformation creates excessive wheel play or wobble.

These conditions can lead to a number of safety and performance issues:

Vibration and Noise

As bearings wear and develop play, it causes the wheels to wobble. This imbalance creates vibration that can be felt in the tow vehicle. It may be most pronounced at certain speeds. Bad bearings also cause grinding, squeaking or rumbling noises.

Difficulty Steering

Excessive wheel play can make the trailer difficult to steer and control. There may be a noticeable delay between turning the tow vehicle and the trailer responding. Loose bearings also put more strain on the hitch.

Tire Wear

A wobbly wheel places uneven pressure on the tire tread. This results in rapid and uneven tire wear. The tire may also overheat from friction if the bearing seizes.

Reduced Braking

Worn bearings allow the drum and brake shoes to move excessively, reducing braking effectiveness. Seized bearings prevent the wheel and drum from turning normally.

Wheel Detachment

In a worst case scenario, worn or overheated bearings can fail completely. If the wheel separates from the axle, it results in an extremely hazardous road situation. The wheel may strike other vehicles or cause the trailer to overturn.

How Often Should Trailer Bearings be Repacked?

Most manufacturers recommend repacking trailer wheel bearings every 12 months or 12,000 miles. However, frequency depends on usage and driving conditions. More frequent repacking is needed if you tow a lot of miles annually, haul heavy loads, or drive on dirt roads or through water regularly. Anytime the wheel end is submerged in water, the bearings should be repacked immediately.

You can have your dealer or repair shop check the bearings annually and advise if more frequent repacking is needed. They will visually inspect for wear, corrosion, smooth rotation and play. Bearings should be repacked whenever excessive play is detected.

Signs That Bearings Need Repacking

Don’t wait until major damage is done. Watch for these signs it’s time to repack the trailer bearings:

• Vibration when towing
• Grinding, squeaking or rumbling noises
• Uneven tire wear
• Excessive wheel play or wobble
• Overheating hub – too hot to touch
• Grease leakage
• Rusted or corroded components

Trailer Bearing Repacking Procedure

Proper bearing maintenance requires careful cleaning, inspection and reassembly. The basic process is:

1. Jack up trailer and secure on jack stands
2. Remove the hubcap, cotter pin and spindle nut
3. Pull the hub off the spindle
4. Thoroughly clean all parts
5. Inspect bearings, races, seals and hub for wear or damage
6. Pack bearings with new grease
7. Install inner bearing and race in the hub
8. Install hub on spindle
9. Install outer bearing and race on spindle
10. Install spindle washer and nut
11. Tighten nut while rotating the wheel
12. Loosen nut then retighten per manufacturer specs
13. Install cotter pin
14. Check for play and smooth rolling
15. Replace hubcap

This requires some mechanical skill and special tools. Most DIYers will take their trailer to a repair shop for bearing repacking. Cost is typically $25-$75 per wheel.

Repacking vs. Replacing Trailer Bearings

Bearings that are in good shape can be cleaned and reused. But at some point, bearings will become too worn and need to be replaced. This requires pressing the old bearing races out and pressing new ones in. Check with your mechanic if you suspect the bearings need replacement.

Bearings should always be replaced if:

• There is visible damage like pitting or cracks
• They have more than .001 inches of runout
• They show signs of overheating (discoloration or deformation)

Wheel bearing seals should be replaced every time the bearings are repacked, since they are damaged when removing the hub.

Can You Tow with Bad Bearings?

It is never safe to tow a trailer with worn or damaged wheel bearings. The risk of breakdowns, accidents and serious injuries is extremely high. You will likely incur major repair costs that could have been avoided. Always have faulty bearings replaced or repacked before hauling your trailer.

Tips for Maximizing Bearing Life

• Use a bearing protectant sealant when repacking
• Always use high quality grease designed for wheel bearings
• Ensure the bearings are properly preloaded
• Check lubricant levels frequently
• inspect tire condition and inflation often
• Have brakes and suspension aligned
• Follow manufacturer’s load limits

Frequently Asked Questions

How much does it cost to repack trailer bearings?

The average cost to repack trailer wheel bearings is $25-$75 per wheel at a repair shop. DIY repacking may cost $15-$30 per wheel for supplies.

Should I use synthetic grease in trailer wheel bearings?

Synthetic grease may provide better protection and last longer between changes. But regular lithium grease is fine for most conditions. Always use a grease designed for high temperature wheel bearing usage.

Can I just add more grease without removing the old grease?

No, you should never just pump more grease in without a complete cleaning and repack. This can cause pressure buildup and seal failure.

Should I rotate trailer tires?

Yes, rotating tires helps promote more even wear. Follow the same guidelines as automotive tire rotation. Tires should be rotated every 6,000-8,000 miles.

How do I know if the wheel bearings are going bad?

Listen for rumbling or grinding noises, look for grease leakage, check for excessive wheel play by rocking the tire, and feel if the hub is abnormally hot after driving.

Can a bad wheel bearing cause vibration?

Yes, excessive wheel play from worn bearings can cause vibration at highway speeds. It may come and go depending on speed and road conditions.

Conclusion

Neglecting to repack trailer wheel bearings leads to a number of problems that can create dangerous towing situations. Sticking to the recommended service intervals, or more often as needed, is crucial to avoid breakdowns and maximize the life of your trailer wheel end components.