Cleaning & Repacking Trailer Wheel Bearings
This is a messy job, but it is possible for you to do it yourself. In order to remove the trail wheel bearings, clean them and repack them, you will need to ensure the trailer is raised and that you have room to work.
Many manufacturers recommend this as part of your yearly maintenance to your trailer, if it is getting regular use or every 20,000 km. There are some items you will need to help you do this yourself:
Step 1: Remove the Wheel
Remove the lug nuts and the wheel, and make sure that the trailer is supported with jack stands and that the opposite wheel is blocked.
Step 2: Remove the Dust Cap
You may need a screwdriver to pry the dust cap loose. After removing this you should be able to see the castle nut, you will need to remove this as well.
Step 3: Remove the Cotter Pin
Take a pair of needle-nose pliers and straighten the end of the cotter pin to be able to pull it out.
Step 4: Remove the Hub
Once you get the cotter pin out, you can then remove the retaining nut and washer, then pull the hub off the spindle. You will want to watch and be careful as the trailer bearings will come out with the hub. Set the bearings aside on a clean surface, that can have grease on it, like newspaper or a rag.
Step 5: Remove the Bearing and Seal
To remove the rear bearing and seal you will want to tap along the rim of the bearing, if the seal is rusted to the hub, just spray a little WD-40 on the back to help loosen it. If the seal is damaged or becomes damages, replace it. Clean all the grease from the bearings, races and seal, you can use something like kerosene or some form of de-greaser to clean these and while you are cleaning them you can inspect them for wear and tear and replace any parts if they look worn. Once they are all cleaned, spray them with brake cleaner and set them aside to dry, wipe the inside of the hub using a clean rag to remove all of the grease, and clean them with brake cleaner as well.
Step 6: Pack Grease into the Bearings
Spoon some of the new grease into the palm of your hand, working from the wide side of the bearing, push the grease into the bearings. Keep pushing the grease into the roller until the cage and rollers are filled, then coat the inside of the hub with grease. You can smear the rest of the grease in your hand over the face of the bearing rollers.
Step 7: Replacing the Seal
Once you have cleaned all the grease out of the hub, you will wipe the fresh grease on the inner race and set the bearing in place, and install the hub and bearings back on the spindle. Remember to position the new grease seal with the open edge of the lip facing in toward the bearing until the seal is fully seated, then wipe a light coat of grease around the inside of the new seal.
Step 8: Reinstall the Bearing
Once you have greased the new inner bearing, you will install it into the assembly. You will insert the inner bearing and the new seal by turning the hub over so the front sides of the wheel studs are face down. Place the inner bearing in the hub and the seal on top. Tap the seal until it sits flush, then apply a thin layer of grease to the spindle and slide it on the hub.
Step 9: Reinstall the Hub
Thread the nut back onto the spindle and turn it clockwise, spin the hub a few times as you tighten to make sure the bearings are seating properly. Tighten the nut firmly, then back the nut up until the hole in the spindle aligns with a space in the nut. Push the new cotter pin (available at National Trailer Parts Warehouse) and bend the ends of the pin to keep it from sliding out. Tap the dust cap back into place and coat the lug threads with an anti-seize compound, reinstall the wheel and tighten the lug nuts. You will do this for each trailer wheel.
Reference Links:
https://www.familyhandyman.com/project/repacking-trailer-wheel-bearings/
https://www.boatus.com/magazine/trailering/archives/repacking-or-replacing-your-bearings.asp
https://www.readersdigest.ca/cars/maintenance/how-repack-wheel-bearings/
https://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/trailer-bearings2.htm
