How to Repack Trailer Wheel Bearings

Trailer wheel bearings carry the full weight of your load and spin thousands of times per mile. Old, dry, or contaminated grease is the number one cause of roadside hub failure. Repacking your bearings about once a year (or every 10,000–12,000 miles) keeps them running cool and prevents a seized hub on the highway. Here is how to do it safely.

Estimated time: 1 hour 30 minutes

Tools You'll Need

• Jack and jack stands
• Lug wrench
• Channel-lock pliers or a brake spring tool
• Rubber mallet
• Clean rags and a parts brush

Supplies

• Marine-grade wheel bearing grease
• New grease seals
• New cotter pins
• Parts cleaner or solvent

Step-by-Step

Step 1: Lift and secure the trailer

Park on level ground, chock the wheels, and loosen the lug nuts slightly. Jack up the axle and set it on jack stands rated for the load. Never work under a trailer held up only by a jack.

Step 2: Remove the wheel and dust cap

Take off the lug nuts and wheel. Pry off the dust cap with channel-locks or a flat screwdriver to expose the spindle nut and cotter pin.

Step 3: Remove the hub

Straighten and pull the cotter pin, then unthread the spindle nut and remove the washer. Slide the hub toward you slightly to pop the outer bearing free, then pull the hub off the spindle.

Step 4: Clean and inspect the bearings

Drive out the rear seal, remove the inner one, and wash both in solvent until all old grease is gone. Inspect the rollers and races for pitting, bluing, or rough spots. Replace any bearing or race that is damaged — always replace bearings and races as a matched set.

Step 5: Pack the bearings with grease

Place a glob of marine-grade grease in your palm and press the wide side of the bearing into it until grease pushes out the top of the rollers. Rotate and repeat until it is fully packed with no air gaps.

Step 6: Reassemble the hub

Set the packed inner bearing into the hub, install a new grease seal, and slide the hub back onto the spindle. Install the outer bearing, washer, and spindle nut.

Step 7: Set the bearing preload

Tighten the spindle nut while spinning the hub until it just drags, then back it off to the nearest cotter-pin slot so the hub spins freely with no play. Install a new cotter pin and tap the dust cap back on.

Step 8: Reinstall the wheel and test

Mount the wheel, snug the lug nuts in a star pattern, lower the trailer, and torque the lugs to spec. After a short drive, feel each hub — warm is normal, hot means the preload is too tight or a bearing is failing.

Need a Hand?

If a hub runs hot, you find a damaged race, or you see heat discoloration, don't risk a roadside failure. Allred Trailer Service can handle the whole job on-site anywhere in the greater Sacramento area — text us at (916) 251-9731.

Frequently Asked Questions

How often should trailer wheel bearings be repacked?

Repack trailer wheel bearings approximately once a year or every 10,000–12,000 miles under normal conditions. Boat trailers that are submerged at launch ramps should be repacked after every use, since water can flush grease from the bearings. Any trailer coming out of long-term storage should be repacked before returning to service.

What grease should I use for trailer wheel bearings?

Use a marine-grade wheel bearing grease rated NLGI Grade 2. Marine-grade grease is formulated to resist water washout — critical for any trailer that sees rain, river crossings, or boat ramp use. Do not mix different grease types; old and new grease can separate and leave bearings dry.

How do I know if trailer wheel bearings need replacing?

Replace bearings and races as a matched set if you find any of these: pitting, spalling, or blue heat discoloration on rollers or races; rough or grinding rotation when the hub is spun by hand; side-to-side wheel play when the hub is rocked; or a grooved or pitted race surface. New bearings cost far less than a roadside hub failure.

Do UFP Vault hubs need the same repacking procedure?

No. Vault hubs use a sealed oil-bath system — there is no grease to pack. Instead, check the oil level through the sight glass and top off or replace the oil annually. For Vault hub part numbers and service details, see our [Dexter/UFP Vault Hub guide](/blog/dexterufp-vault-hub-part-numbers-for-37k-and-42k-trailer-axles).

What is the correct spindle nut adjustment for a trailer hub?

The correct procedure is a sequence, not a single torque value. Tighten the spindle nut to approximately 50 ft-lbs while rotating the hub to seat the bearings, then back off completely, finger-tighten, and back off to the nearest cotter-pin slot. The hub should spin freely with no perceptible end play and no binding.