go to a big box store. go to the metal bar stock section- usually they're in the pick-and-choose nuts and bolts area. Alternatively, just ask. (I like local hardware stores, they''ll have it too, somewhere. better selection of pick-and-choose hardware, too.)
Get some smooth rod slightly smaller in diameter than the rod there. use the rod to knock it out- either in a press (if you have access to one) or by setting it in some kind of clamp and pounding on the rod with a hammer.
if their only options for bar stock are expensive, you can get a bolt that's also slightly undersized and use that.
for the record, the wheel looks like it's an absolute gonner, so you're probably going to have to get more parts anyhow.
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/pin to fall through. the big thing is you don't want it flying anywhere when you start applying force.
a hydraluic press would push it out with more control on such a set up, but most people generally don’t have them. that's why I suggested the hammer-and-rod set up. what that will do is let you apply force diretly to the pin; and with it slightly undersized, it won't replace the pin.
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. amazon has plenty of kits- but try and match brand to brand.
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.