Hubs and Brakes
Next step is to remove the hubs, to expose the braking system.
I didn't take any pictures of the process, on the assumption that if you were tackling this job, you already knew...
However, in hindsight, I've chosen to at least describe the process for those who have never done so.
First remove the dust cap in the center of the hub.
You can use a large pair of channel lock pliers, or a screwdriver to pry it out.
The dust cap is a friction fit part.
Try to be careful, most old dust caps are an odd size, and can be hard to find.
Next, use a wire cutter, or pliers to remove the cotter pin in the castle nut (found under the dust cap).
Save it as a reference (for sizing new ones) but do NOT re use it!
Cotter pins cost only a few cents each, and are the safety that keeps the wheel from departing your trailer at 65 mph if the nut comes off!
For the next step, you'll want to have some old rags, or gloves.
With one hand (or a helper) hold the hub to the backing plate, with the other hand, remove the axle nut.
At this point, the hub may slide off the shaft and onto your foot...Be careful, the hub is very heavy!
With the nut removed, carefully slide the hub forward a couple inches.
There is a flat washer behind the nut, and then the outer wheel bearing that will slide off the axle shaft when you slide the hub forward.
Both these parts are very greasy (slippery).
Once out of the way, get a good hold on the hub, and remove.
The inner wheel bearing is held in place by the grease seal, on the other end of the hub, once the seal is removed, the bearing will come out.
The need for replacing bearings, races, and seals is something you'll have to determine when you have them in your hand.
If you choose to re-use them, at least get them very clean (de-grease them) before packing with new grease.