How to Replace the Axel Bearings in a Boat Trailer

Annual service of boat trailer axle bearings can delay the need to replace them, but at some point they will need to be replaced. Constant heating from being towed down the road and sudden cooling when the trailer is backed into the water can result in water getting into the hubs. This water causes the bearings to become corroded and pitted, resulting in noisy bearings that will eventually fail. Bearings can be replaced with simple tools the average handyman already owns.

Things You'll Need

• Wheel chocks
• Jack
• Jack stand
• Hammer
• Chisel
• Pliers
• Hardwood dowel
• Brass drift
• Bearing race and seal installation kit
• Ratchet and socket to fit the spindle nut
• Replacement bearings
• Replacement grease seal
• Cotter pin
• Grease gun and marine wheel bearing grease
• Rags

Instructions

Bearing removal

1. Chock the wheel on the opposite side of the trailer from your starting wheel.

2. Jack up the side of the trailer you plan to start the bearing replacement on, and support with a jack stand.

3. 

   Place the point of a chisel between the ridge on the back edge of the hub dust cover and the hub, and lightly tap with a hammer to loosen the dust cover. Turn the wheel slightly and place the chisel in another spot and tap again. Repeat until the dust cover is removed.

4. 

   Remove the cotter pin and spindle nut.

5. Remove the thrust washer and outer bearing. Shake the wheel from side to side to cause the bearing to come out of the hub, where it can be grasped and removed easily.

6. Pull the wheel and hub off the axle. Place interior-side down on a piece of newspaper or rag.

7. 

   Insert the hardwood dowel through the center of the hub until it rests on the back of the inner bearing. Strike with the hammer until the inner bearing and grease seal are removed.

8. Place the brass drift through the hub and hold it against the lip of the inner bearing race. Strike with the hammer, then move it about a third of the way around and repeat. Do this until the race is removed from the hub. Turn the wheel over and remove the outer bearing race in the same manner.

9. Remove all the old grease from the hub with rags.

Installing the replacement bearings

1. 

   Chose the appropriate driver from the bearing race and seal installation tool set to fit the inner bearing race. The driver should fit against the tapered inside of the bearing race with no play. Strike the tool with a hammer until the race is seated completely in the hub.

2. Turn the wheel upside down and install the other bearing race. Coat both races with a thin layer of wheel bearing grease.

3. 

   Pack the new bearings with marine wheel bearing grease. You can do this with a bearing packing tool, or by hand. If you pack the bearings by hand, be certain the grease is actually pushed in between all the bearing races. The grease should form a peak between the bearing retainer and the inner race.

4. Insert the inner bearing in the race and then insert the grease seal in the hub. Drive the grease seal in with the same driver you used to install the inner bearing race, but turn the driver over first.

5. Wrap the axle threads with tape (you can use masking tape, duct tape or any other smooth tape).

6. Lift the wheel into place and slide onto the axle until seated.

7. Install the outer bearing, thrust washer and spindle nut.

8. 

   Place the socket on the spindle nut and tighten while turning the wheel until you feel resistance. Then back off the adjustment and tighten again until there is no play when you shake the wheel, but the wheel still turns freely.

9. Use a new cotter pin and bend the ends over to secure. If the slots in the nut do not line up with the hole in the axle, back out the nut slightly until the cotter pin can be inserted.

10. Replace the dust cover and pump several pumps of grease into the hub.

11. Repeat on the other side of the trailer to complete the axle bearing replacement.