How to Replace Races and Wheel Bearings on a Boat Trailer

by K.K. Lowell

Boat trailer wheel bearings have tough lives. They heat up when you're towing the boat, then cool suddenly with a dunk in the water when you unload it. Over time, this can introduce water in the hub. This water can rust and erode the bearing surfaces and necessitate bearing replacement. If you own a few simple hand tools, you can replace the races and wheel bearings on your boat trailer in an hour or two.

Bearing and race removal

Place the trailer on a level, solid surface such as a garage floor or driveway.

Jack the trailer up and support it securely with jackstands.

Place the point of a small cold chisel between the ridge on the dust cover and the edge of the bearing hub. Tap lightly with a small hammer to remove the dust cover. Turn the hub as necessary to facilitate removal of the cover without distorting it.

Remove the cotter pin in the center of the large spindle nut.

Remove the spindle nut by turning it counterclockwise.

Shake the wheel and tire to force the bearing out of the hub. Remove the bearing with your fingers when you can grasp it.

Pull the wheel and tire off of the spindle.

Remove the excess grease from inside the hub.

Place the wheel and tire on the ground, inside down.

Drive the inner bearing and seal from the hub with a hardwood dowel. Place the dowel through the hub and strike with a hammer until the bearing and seal fall out.

Place a brass drift through the hub and against the inner edge of the bearing race. Move around the race while striking it with a hammer. This will force the race from the hub. Turn the wheel and tire over, and repeat with the outer race.


Prepare a clean work surface on your bench. Lay a clean rag or paper towel down to receive the new bearings.

Unpack the bearings and pack with grease. If you do not have access to a bearing packing tool, you can pack the bearings carefully by hand, being sure to fill the bearing completely with grease.

Use the proper-size race installation driver and insert the new race into the hub. The proper tool will fit closely inside the new race. Drive the race by striking the installation tool with a hammer until the race is fully seated in the hub. Repeat for the other race.

Coat the new races with a thin layer of wheel bearing grease.

Place the wheel and tire outside down on the floor and insert the inner wheel bearing. Drive the new seal into place using the seal driving tool and a hammer. The tool will drive the seal to the proper depth.

Clean the spindle of all old grease. Wrap the threads on the spindle with tape.

Lift the wheel and tire onto the spindle and slide back into place. Remove the tape from the spindle.

Install the outer bearing, thrust washer and adjusting nut. Tighten the nut as much as you can with your fingers. This is easier if you wiggle the wheel as you tighten the nut. Do not use a wrench on the nut at this point.

Using a socket, tighten the adjusting nut while turning the wheel. Tighten only until you feel a drag.

Back off the adjusting nut until it is loose, then retighten approximately 1/4 turn. The wheel should turn freely, with no play in the bearing when you attempt to shake the wheel.

Replace the cotter pin with a new one; bend the ends to lock it in place.

Replace the dust cover by tapping it in place. To avoid damaging it, use the chisel against the ridge to drive the cover in place.

Pump several squirts of grease in the grease fitting.

Carefully remove the jackstands from the trailer frame.


  • check Use a high-quality grease specified for marine use.


  • close Avoid hitting the chisel hard enough to damage the dust cover. Do not coat just the outside of the bearing with grease, because this does not supply adequate lubrication to the bearings and inner race. Do not over-tighten the adjusting nut; this can damage the bearing and race.

Items you will need

About the Author

K.K. Lowell is a freelance writer who has been writing professionally since June 2008, with articles appearing on various websites. A mechanic and truck driver for more than 40 years, Lowell is able to write knowledgeably on many automotive and mechanical subjects. He is currently pursuing a degree in English.

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