with a torsion axle definitely needs to be replaced if it is original. I would suggest contacting Colin Hyde Restorations about a replacement. He can arrange it to be dropped shipped to you (with or without brakes installed).
With a single axle trailer and living in the western US. Suggest you consider upgrading to EOH (electric over hydraulic) disc brakes. Like us, any direction you go requires elevation changes. It's not an inexpensive upgrade, but provides a lot of piece of mind on those long downgrades.