How to Repack Boat Trailer Wheel Bearings

Repacking boat trailer wheel bearings is a messy process, but a necessary part of trailer maintenance. You’ll want to have plenty of gloves and a whole box of rags to deal with the greasy mess.

Your boat’s trailer wheel is likely to have one of three different types of caps on the end of it. One is just the standard cap. The second type is the Bearing Buddy setup, and the third one is a cap with a rubber insert and a zerk fitting. For the purposes of this project, we’re focusing on the Bearing Buddy setup found on our boat trailer. Watch the video above or read on below to learn how to repack trailer wheel bearings.

Tools and Supplies - Repacking Trailer Wheel Bearings

  • Ratchet and extensions
  • Dead blow hammer
  • Soft blow hammer
  • Bearing packer
  • Shop rags
  • Side cutters

Buy trailer wheel bearing kit

Buy trailer wheel Bearing Buddy

On this particular setup, if you only fill the grease from the outside, the grease that’s the oldest is what's still running and getting abused on the bearings inside. 

How to repack boat trailer wheel bearings Bearing Buddy

So just by adding more grease to it, you're not really flushing the old grease out. And that's the reason you need to repack the bearing so often. The wheel hub grease only has so long of a lifespan. And after a while it breaks down, starts to get contaminants in it from the natural wear of the bearings, and then it fails. If that happens, it’s possible to lose the entire trailer wheel.

Boat trailer wheel

Missing boat trailer wheel

On our trailer, there wasn’t enough grease to get the job done, and eventually the outer bearing failed, and ate away the locking nut and cotter pin until the entire wheel came off. This is why we recommend you repack trailer wheel bearings at least once a year. 

Boat trailer wheel bearing

As for what grease to use, the manufacturer doesn't really matter, but you want to choose a grease with the best rating for a high temperature application. We’re going with a grease that has a high NLGI rating of GC-LB. 

Boat trailer wheel bearing repacking grease

How to Repack Boat Trailer Wheel Bearings - Bearing Buddy Setup

Step 1. Remove the wheel from the trailer, followed by the Bearing Buddy, using a soft blow hammer to hit it at an angle to knock it off. 

How to repack boat trailer wheel bearings

PRO TIP: Clean each area with rags and contact cleaner as you’re taking everything apart to reduce the mess you’ll have to deal with as you go along.

How to repack boat trailer wheel bearings remove bearing buddy

Repack boat trailer wheel bearings bearing buddy removal

Step 2. Use side cutters to straighten out and remove the cotter pin from the axle’s castle nut. 

Repack boat trailer wheel bearings

Step 3. Remove the axle nut, followed by the washer behind it.

Repack boat trailer wheel bearings remove axle nut

Repack boat trailer wheel bearings remove axle nut washer

Step 4. Remove the wheel hub from the trailer and wipe the axle clean.

Repack boat trailer wheel bearings remove wheel hub

Repack boat trailer wheel bearings remove hub

Step 5. Pry out the seal and the inner wheel bearing from the hub. 

Repack boat trailer wheel bearings remove bearing

Step 6. Clean out the old grease from inside the wheel hub. 

Repack boat trailer wheel bearings clean hub

Step 7. Inspect the outer and inner bearing race surfaces to make sure there’s no pitting, imperfections or damage of any kind, and replace them if necessary. 

Repack boat trailer wheel bearings inspect hub

NOTE: Our bearing races were recently replaced and in good shape, so there was no need to replace them again.

Repack boat trailer wheel bearings hub inspection

Step 8. Replace the wheel bearing seals

Repack boat trailer wheel bearings new seal

Repack boat trailer wheel bearings replace seal

Step 9. Use a bearing packer with fresh grease inside it, then place each bearing (one at a time) inside, tighten it down and hold it in place. Next, apply a fair amount of pressure on it to force the new grease up into it and force out the old grease.

Repack boat trailer wheel bearings grease packer

NOTE: You can buy a bearing grease packer at just about any automotive store.

How to repack boat trailer wheel bearings grease packer

Constant pressure will start pushing out the old grease. Check to make sure the old grease has been pushed out and the new grease has been applied. 

Repack boat trailer wheel bearings grease

NOTE: Grease is pretty viscous, so if it's cold where you are, you may want to consider bringing in your grease up to room temperature. Otherwise you're going to have a tough time forcing out the old grease and getting the new grease in there.

Repack boat trailer wheel bearings new grease

As mentioned, GC-LB grade is a good choice for grease, since it’s super sticky and lasts a long time. 

Repack boat trailer wheel bearings grease recommendation

Repack boat trailer wheel bearings grease packing

Repack boat trailer wheel bearings grease application

Step 10. Load up the bearing race in the inner part of the hub with some fresh grease, then drop in the inner bearing. 

Repack boat trailer wheel bearings grease hub

Repack boat trailer wheel bearings install inner bearing

Step 11. Tap in the new bearing seal flush with the hub. 

Repack boat trailer wheel bearings new bearing install

Step 12. Pack in the area in between the bearing and the seal with grease, making sure you get it all the way around the seal itself. 

How to repack boat trailer wheel bearings new bearing install

Step 13. Inspect the axle for pitting and other damage. Use an emery cloth and some contact cleaner to clean up the axle.

How to repack boat trailer wheel bearings axle

NOTE: If the axle on your boat’s trailer has pitting like ours does, it will eventually need to be replaced because it's going to eat through the seal faster than it should. 

How to repack boat trailer wheel bearings axle cleaning

Repack boat trailer wheel bearings axle cleaning

Step 14. Grease the axle, then reinstall the wheel hub. Turn the hub while you're placing it over the end of the axle so it doesn't grab one of the edges of the seal and pull it in the wrong direction. 

Repack boat trailer wheel bearings axle grease

Repack boat trailer wheel bearings hub reinstall

Step 15. Install the outer bearing, washer and castle nut onto the axle, then hand-tighten the castle nut just enough to snug it up, and rotate the hub a couple of times. 

Repack boat trailer wheel bearings outer bearing install

Repack boat trailer wheel bearings axle washer install

Repack boat trailer wheel bearings axle nut install

Step 16. Rotate the hub as you’re tightening the castle nut with a socket and wrench to force out a little bit more grease and seat it against the race. Next, back it off about an eighth to a quarter of a turn to where it has just a little bit of play but spins easily. 

Repack boat trailer wheel bearings axle nut torque

Repack boat trailer wheel bearings castle nut torque

Step 17. Install a new cotter pin onto the castle nut.

Repack boat trailer wheel bearings castle nut cotter pin

Repack boat trailer wheel bearings axle nut cotter pin

Step 18. Install the Bearing Buddy by gently tapping it in first with a dead blow hammer, then wiping off the excess grease with a rag, and using a soft blow hammer to get it seated properly. 

Repack boat trailer wheel bearings Bearing Buddy install

Repack trailer wheel bearings Bearing Buddy

Repack boat trailer bearings Bearing Buddy

Repack boat trailer bearings Bearing Buddy installation

Step 19. Use a grease gun to fill up the cavity of the Bearing Buddy just for good measure, then install the Bearing Buddy cover and you’re done. 

Repack boat trailer wheel bearings grease Bearing Buddy

Repack boat trailer wheel bearings

Boat trailer wheel bearings Bearing Buddy

 

 

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