I had two sets of classic 44s I bought from here years ago. Both had loose kingpins. I hammered them out, put some “steel epoxy” in there and hammered there and hammered the kingpins back in. Both sets have held up well for years. Other set I skated until the hanger split in half and the kingpins were ground down so much that the nuts fell off cuz they were ground down so much they wouldn’t hold anymore. So the kingpins definitely got some stress.
If you hammer the kingpins out, make sure to keep the nut on so you don’t fuck up the threads of the kingpin. Also support the baseplate not only from the sides as the baseplates could then easily bend. When hammering the kingpin back in I used a big bolt as an aid as the kingpin goes inside the baseplate where you can’t reach with a hammer. When hammering the kingpin back in it’s also important to support the baseplate properly so you won’t bend it. I did it on my mate’s vise and it all worked out beautifully.
Lots of text but it really wasn’t that much trouble and it was nice to do so I definitely recommend it.