How to Repack Boat Trailer Wheel Bearings 

A boat trailer’s wheel bearings should be checked and repacked with grease at least once a year, otherwise they can fail and lead to extensive damage or loss.

It’s easy for boat owners to overlook inspecting and repacking their trailer’s wheel bearings each year. The good news is that checking and repacking a trailer’s wheel bearings is easy trailering maintenance that can be done in less than an hour. Here are some steps to follow for repacking trailer wheel bearings.

Step 1. Park the trailer on a level surface, then jack the wheel up and use an axle stand to support the weight of the trailer. 

NOTE: Never work on a boat trailer with only a jack to support it.

Step 2. Remove the dust cap or the bearing protector from the end of the axle and clean off the grease with a rag.

Step 3. Remove the cotter pin holding the axle nut in place and discard it, then remove the axle nut. Next, remove the cover washer and the wheel bearing from within the hub. Put all the parts into a solvent bath to remove all of the old grease, then take them out and let them dry completely.

Step 4. Remove the wheel and hub from the axle and clean the grease off the axle with a rag. Inspect the axle for scratches and if there are any, use a very fine grit wet-and-dry paper to remove them.

Step 5. Remove the seal from the inner side of the hub and discard it. Remove the inner wheel bearing and clean it as you did the outer bearing.

NOTE: It’s unlikely you’ll be able to remove the seal without damaging it, so it’s best to replace it with a new one. Don’t reuse the old bearing seal.

Step 6. Clean the grease from inside the wheel hub, then inspect the bearing races for any signs of wear and replace them if necessary.

PRO TIP: A typical wheel bearing kit is inexpensive, and will include bearings and seals. 

Step 7. Inspect the wheel bearings for wear and discoloration, which is a sign of heat stress. If either one of the bearings shows signs of wear or overheating, replace them both.

Step 8. Repack the wheel bearings with grease by hand or with a bearing packer tool. Next, repack the races and the inside of the hub with grease.

Step 9. Replace the inner bearing and carefully tap the new seal into place with a hammer. Next, replace the hub on the axle, followed by the outer bearing, the washer and the axle nut. 

NOTE: Don’t over-tighten the axle nut. Tighten it until there’s slight resistance to the wheel turning freely, then back the nut off 1/6th of a turn. When correctly tightened, there should be no lateral play in the wheel and it should spin freely on the axle without resistance.

Step 10. Secure the axle nut with a new cotter pin, which keeps the axle nut from coming loose and the hub from falling off the axle. Replace the dust cap or bearing protector and you’re done.

PRO TIP: If your trailer doesn’t have bearing protectors, now would be the ideal time to fit them, particularly if your trailer is used in salt water. They’re inexpensive and help prolong the lifespan of the wheel bearings.

With the axle stand removed and the trailer lowered off the jack, you’re all set for the year. No need to worry about a trailering safety catastrophe due to your trailer’s wheel bearings failing.