How to Replace Wheel Bearings on a Boat Trailer

Time spent maintaining your boat trailer can translate into fewer problems getting to the water. The wheel bearings on a boat trailer allow the wheel to turn without friction. Newer trailers are made with a wheel bearing protector system that still requires regular inspection. Wheel bearings are packed with grease that will leech through seals, harden with age or dissipate while submerged in the water at boat ramps.

Things You'll Need

  • Rubber mallet
  • Seals
  • Shop rag
  • Marine grease
  • Grease gun
  • Gasket sealer
  • Cotter pin

Packing Wheel Bearings

  • Remove the dust cap. It may need to be pried off. Take out the cotter key. Then remove the nut and washer that hold the bearing cone. Take off the nut and washer to the bearing cone and pull the hub out. The outer bearings will fall out; collect them and place them aside. Remove the axle seal and discard it. Remove the inner bearings and place them in a location separate from the outer bearings.

  • Clean each part and inspect them for signs of damage or wear. Replace parts that are worn or have damage from excessive heat. Pack the marine grease into the bearing, forcing in as much grease as you can. The grease keeps air out of the system. It is critical that marine grease be used as it has water-resistant properties.

  • Place the inner bearing back in the wheel hub. Install a new seal and use the gasket sealer. Place the tire and hub back on the spindle, but do not damage the new seal. Insert the outer bearing and attach using the washer and nut. Line the nut with the hole in the axle and install a new cotter pin. Replace the dust cap. Fill the hub with marine grease, using a grease gun.