Are you sure it’s not just the front ring rotating and not the whole front element? I had that happen once.I got lucky on ebay, for £30 I picked up an Agfa Isolette II with a Solinar 75mm F/3.5 on the front. Bellows are relatively new so no leaks and the focus needs a little energy but not that I would say is tough to move. It is very smooth.
I ran a test roll of very expired Lomography 400 through it and only a few prints were any use. I have a roll of XP2 in there right now.
Probably going to get chastised for this, but try A DROP of naphta or a cotton swap dipped in naphtha held to the crack of the helicoid, to let it wick in.
More than that will get into the lens and necessitate unscrewing of the front element.
This could help get the focus looser.
Let it evaporate over 24 hours after exercising it, and see if it helped.
If there is only some improvement try again.
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