Reply number six
The white bushings are not removable from the stainless steel shaft they’re permanently assembled. You have to it’s the round black plastic thing secured with four screws underneath filter .
I can see from your picture that the bronze bushing has come out of your wash arm. That part is supposed to be permanently assembled into the wash arm, if your washer arm still in good condition, remove the bushing from the stainless steel shaft, any epoxy it back into the wash arm otherwise, the wash arm will need to be replaced. It’s not meant to be operating this way.
It looks like this dishwasher and reply number six ihas quite a mineral build up. I can’t be doing that great job on the glassware with that kind of build up you need to be using hotter water, better detergent and probably a lot more of it.
John.