Nothing lasts forever, including boat trailer bearings. Trailer wheel bearings need to be replaced because backing the trailer into the water to launch a boat will wash the grease from wheel hubs and bearings. Towing the boat trailer with grease-free wheel bearings is the best way to destroy them. Replacing trailer bearings is relatively simple, especially for the accomplished do-it-yourselfer. Routine wheel-bearing maintenance is the best way to avoid premature bearing failure.
Things You’ll Need:
- Lug wrench Alligator jack Flat tip screwdriver Cotter pin extractor Socket and ratchet Ball peen hammer Copper or brass drift pin Solvent Rags Wheel bearing grease New wheel bearings New wheel bearing seal
- Lug wrench
- Alligator jack
- Flat tip screwdriver
- Cotter pin extractor
- Socket and ratchet
- Ball peen hammer
- Copper or brass drift pin
- Wheel bearing grease
- New wheel bearings
- New wheel bearing seal
Using a lug wrench, loosen, but do not remove, the wheel lug nuts or lug bolts. Place an alligator or floor jack under the trailer axle and raise the trailer until the wheel clears the ground. Do not rely on the jack to keep the trailer in the air. Once it is raised, support the trailer with jack stands or blocks.
Once the trailer is jacked up, remove the wheel lug nuts or bolts and lay them aside. Remove the tire and wheel assembly.
Using the flat blade screwdriver, pry off the grease cap from the end of the wheel hub. If the trailer is equipped with bearing buddies (self-lubricating hubs equipped with a spring-loaded piston), pry them out of the wheel hub.
Remove the cotter pin in the end of the axle with a cotter pin extractor or a pair of pliers. With the proper size socket and ratchet or open-end wrench, remove the wheel nut. Slide the wheel hub off the axle shaft.
Clean out the remaining grease with a good solvent and drift out the grease seal and bearing races–there is an inner and outer race–from the wheel hub with a brass or copper drift pin and ball peen hammer. A press with the proper inserts also works well to remove them.
Installing New Bearings
Clean the wheel hub thoroughly with a good grease remover or solvent. Dry it and inspect the interior of the hub raceways for damage and excessive wear.
Install the new bearing races into the wheel hub. Use a press to install them or use a copper or brass drift pin and hammer, tapping them gently into place. Make sure each race is bottomed out in its recess.
Load the new bearings with a good grade of wheel bearing grease like molybdenum or lithium grade bearing grease. Use a bearing packing tool or place some grease in the palm of your hand and work the grease into the bearing with your fingers.
Place the inner bearing in the hub and tap in the new grease seal. Slide the hub into position on the axle shaft. Press the outer bearing into position in the outer race. Install the axle nut washer and axle nut. Torque the axle nut to the specified torque setting. With a castle nut, tighten the nut until it is snug, then rotate the wheel hub. Back off the castle nut until it lines up with the cotter pin hole in the shaft. Install the cotter pin.
Reinstall the bearing buddies and pack the wheel hub with a grease gun loaded with the same grease used to load the bearings until the bearing buddy piston moves outward. Reinstall the wheel and tire assembly and remove the jackstands.