12 Steps To Repacking Or Replacing Your BearingsBy Pat Piper
Published: Fall 2013
If you choose to tackle this job yourself, here's a general guideline.
Jack the trailer tire on one side high enough so that the tire spins freely and place a jack stand beneath the frame. Chock the opposite trailer wheel. Some will leave the trailer connected to the tow vehicle to ensure there is no movement. Shake the tire up and down and from side to side. If there is movement, chances are good the bearings are bad. Spin the tire and listen for sounds. In many cases, bad bearings can be heard but be aware this can also be nothing more than brake pads or shoes catching the hub.
Remove the dust cover or Bearing Buddy with a screwdriver. If the grease is milky, water has entered the bearing assembly. If the grease has a different color, it can mean newer grease was added. Wipe all grease away with a rag or towel.
Now remove the cotter pin, castle washer (some trailers have castle-style axle nuts — see diagram — in which case there's no castle washer), axle nut, spindle/axle washer and set aside for safekeeping as you'll be using them again. Shake the tire and the outer bearing should come off. Wipe away bearing grease (look for evidence of metal, which points to a bearing or race failure) and inspect for signs of wear including discoloration (a gold color is evidence of heat) and scoring, pitting or dents. If you see any of these, it's time to replace, rather than repack, the bearings. Pull the hub off the spindle and lay it with the inner sidewall facing up. Inspect the spindle for any visible damage and then, feel it with your hand. The surface should be smooth. NOTE: Avoid cleaning bearings and races with gasoline because this can harm the inner seal; paper towels and rags will do the job.
Remove the grease seal. Notice the grease on the inner hub in this photo. That's proof the inner seal has failed. Use channel locks or a seal puller to remove the seal. Remove the inner bearing and inspect it just as you did with the outer bearing in Step 3. NOTE: Anytime you remove the inner seal, replace it.
Just like the outer bearing, the inner bearing is seated in a race, also called a bearing cup or a bearing cone. If the bearings are in good condition, remove all the remaining grease in the hub and inspect both the inner and outer races for pitting, scars and/or discoloration. If everything looks good, all you need to do is repack with fresh grease and a new seal and cotter pin (Go to Step 7). However, if any show signs of wear, it's time to replace everything. NOTE: If a bearing shows wear but the race looks fine, you still replace both.