How to Replace Hub Bearings on a Trailer

How to Replace Hub Bearings on a Trailer
Replacing the hub bearings on a trailer is a process that requires many steps, none of which can be bypassed. Because a wheel is made up of many parts, you have to remove parts to reach the hub bearings and then inspect, pack and reinstall those parts once new hub bearings are installed. Trailer wheels are generally smaller than car or truck wheels, so there are many more revolutions per mile. Boat trailer wheels are regularly immersed in water. Both of these factors contribute to trailer bearing wear.


Difficulty: Moderately Easy

Things You’ll Need:
  • Flathead screwdriver
  • Mallet
  • Cloth or paper towels
  • Seal
  • Bearings
  • Race
  • Bearing grease
Step 1
Remove the tire and wheel.
Step 2
Remove the grease cap on the spindle with a flathead screwdriver. You will see the castle nut, which is used to secure the hub and bearings in place.
Step 3
Remove the cotter pin that locks the nut onto the spindle. You will see a tang washer.
Step 4
Clean grease from the nut. Feel inside the notches of the castle nut for a "tab." Force the tab back, in the direction of the spindle.
Step 5
Look for a "cage" encased around the nut. Remove the cage with a screwdriver. It will snap off. Remove the nut.
Step 6
Grip the hub with a cloth or paper towel and slide it off the spindle. If the inner bearing and seal don't come off with the hub, carefully tap them off the spindle with a mallet.
Step 7
Pull apart the hub. Remove the outer bearing and spindle washer.
Step 8
Remove the inner bearing and seal. Discard the seal. Find sizing information stamped in the rubber part of the seal or measure its inner and outer diameters. You will add a new seal shortly.
Step 9
Throw out the old inner bearing. If you do not know what size bearing you need, look on the data plate, which is located on the side of the bearing, for this information.
Step 10
Remove the races with a flathead screwdriver and a mallet. Tap the races around their rims (so they don't bind) to work them gradually out of the hub. You will add a new ones shortly.
Step 11
Use a cloth or paper towels to remove excess dirt from the inner part of the hub. This step is essential and will help the reinstallation process. Clean the spindle in the same way.
Step 12
Put the hub back together starting with new races. Fit the slender edges towards the outside and force the races forward until they are in as far as they will go. Tap them around their rims with a wooden dowel and mallet.. Avoid metal-to-metal contact with the face, or bearing surface, of the race.
Step 13
Apply grease to the outside of the race.
Step 14
Fill your hand with grease. The next step is to pack the inner and outer bearings with grease. Rotate the bearings in your hand allowing every part to fill with grease.
Step 15
Reinstall the inner bearing and seal with the seal going on top of the bearing.
Step 16
Grease the spindles.
Step 17
Place the hub back on the spindles.
Step 18
Attach the outer bearing. Force the bearing back until it is flush with the race.
Step 19
Attach the washer and spindle nut. Tighten completely, then back it off just a little (about 1/16 of a turn). Install the tang washer and castle nut.
Step 20
Attach the cotter pin so it is aligned with the castle nut. Test for movement in the hub the hub should spin easily, but there should be no lateral play.
Step 21
Secure the cotter pin. Force the pin through the hole of the spindle and notches on the nut. Separate the bottom of the pin so it extends outward to the left and right.

Article Written By Charlie Gaston

Charlie Gaston has written numerous instructional articles on topics ranging from business to communications and estate planning. Gaston holds a bachelor's degree in international business and a master's degree in communications. She is fluent in Spanish and has extensive travel experience.

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