It's possible to put new sleeves on the axles of your trailer, I'd imagine. They provide a new bearing surface as well as a better seal for the races. I'm not sure how they'd work with a brake system, but it's worth checking out. You might also be able to replace the axle-- an easy task on a trailer without brakes. Since I've never owned a trailer with brakes, I'm not sure what you'd have to do in your case, but the cost would be less than a new trailer for sure.

Westside Marine in Port Townsend does sleeve jobs; they also handle King Trailers. Call Randy or Mark at 360/379-5688. They do good work.