"Tim Ward" wrote

Yet another clueless response:
Have you checked toe-out/in on the trailer wheels?
Tim Ward

Most bought trailer axles have no provision for toe in/out. They are dead
straight.

A big clue came when the OP said he could get one wheel to lift off the ground,
just by pushing back and forth on the trailer, and get it rocking back and
forth. Sway from toe in/out is not a problem here.

Wider axle, and more weight on the axle, and less on the ball. That is what is
needed.
--
Jim in NC