From this post, I got the idea to remove and replace the wheels altogether using a hacksaw.
Here’s what it looks like right now. My problem now is that I can’t remove the leftover metal shaft from the caster wheel.
I’ve tried using some lubricant and hammering it with a screwdriver but it didn’t budge.
I would suggest a bench vise. The beefier the better (but be careful not to clamp down too hard on the plastic.)
One way to do it would be to use your typical woodworking clamps c-clamps, or whatever to press it against the top of a vice or a pair of blocks split enough to let the bolt come through.
a hydraluic press would push it out with more control on such a set up, but most people generally don’t have them.
again, though. generally the entire caster wheel assembly would be replaced instead of specific parts of the assembly. these kinds of wheels are not made to be taken apart to be repaired- which is why you’re having all this difficulty.