You will need to use a lifting jack, such as a bottle jack, to get the trailer up off the ground. Make sure to do this on a hard, flat surface. You do not need to go under the trailer for any part of this process.
The dust cap is also known as a grease cap. It covers the nut that holds the hub assembly to the spindle shaft of the trailer. You need to remove it so you can take the hub off the spindle and access the bearings.
The cotter pin is also known as a split pin. You need to pull it out so you can loosen the adjusting nut to remove the hub assembly.
Some adjusting nuts are surrounded by a cage-like structure that secures them even more. If you see this, you can pry it up using your flathead screwdriver to free the nut so you can loosen it.
If the hub doesn’t slide off easily, try rocking it gently back and forth to loosen it. You can also try using a mallet to gently tap the back of the hub assembly in a few different spots to knock it loose.
Each bearing consists of a pair of races, or rings, that hold the ball bearings in between them, called the outer race and inner race. When you pull the bearing out, it will be the whole piece consisting of these 2 rings with little metal balls inside them.
The inner bearing is held in place by a seal, so you have to knock it out from the other side to pop the seal out with it. You can’t just lift it out as you did with the outer bearing.
A punch is a metal rod with a sharp tip at 1 end and a blunt end on the other side. If you don’t have a punch, you can also use a wooden dowel rod as a punch to knock the inner bearing out.
Grease gets dirty over time, so it’s important to remove the old grease and relubricate everything with new, clean grease.
You can blow-dry the parts with compressed air if you have it available. If not, wipe them dry with a clean rag and let them completely air dry before applying new grease. Kerosene can cause skin irritation after prolonged contact with skin, so wear a pair of rubber gloves while cleaning to avoid this. You will also need to dispose of dirty kerosene at a hazardous waste collection site.
This will make reassembly easier and also help with cooling.
Trailer bearings are tapered, so 1 side is slightly larger than the other.
You don’t need to put lubricant where the seal will sit on top of the inner bearing. [13] X Research source
The lip of the seal is the non-metal part of the seal. It needs to face the bearing so it holds the grease in.
Your bearings are now installed and you can put the hubs back on the trailer.
The hub will slide on easily as long as you lubricated the spindle shaft enough. If not, then set it down again and apply a little more grease to the shaft.
To make sure the adjusting nut is properly tightened, tighten it all the way once, loosen it a bit, tighten it again, loosen it again, then finally tighten it all the way.
Keep in mind that once you secure the cotter pin in place, the adjustment nut can’t be turned anymore.
The dust cap protects the outer bearing and grease from getting and dust and dirt in it.
You can now take your trailer for a test drive!
