Ignore a little slop and keep it greased every 10 hours as you won't like the price of the pins from Kubota.... and, far as I know, Kubota don't offer an oversize pin or a bushing kit for the loader bushings themselves which will be a weld in proposition anyway. Have that scenario going on with one of my loaders, both upright towers are sloppy in the upper pivot, so sloppy that they can wave at me.
I'm ignoring it for now because of the work involved. The loader has to be taken apart and the uprights need to be jigged on a boring mill and line bored oversize and a new bushing welded in. Lots of grunt and machine work. I have both the machine tools and the welder but I lack the ambition to do it. So, until a pin fails, I'll let them stay 'friendly' and wave at me.
That applies in spades to the bucket linkage. The parallel linkage arms really wear into the pins and again, only cure is line bore and weld in a new bushing along with pin replacement.
best preventative treatment is regular greasing every 10 hours with a good quality synthetic high pressure grease.
Dry pivots wear quickly. I know greasing is a mess but it does wipe off with a disposable shop towel.
When it's time for me, I'll most likely make up my own pins from bar stock and bushings from seamless steel pipe.