I took the focus ring off mine as the first step to solve the probelm you are facing. Loosen, do not undo the three tiny screws. Getting the thread to start again is hell.
I used a dabbing of white gas/naptha applied with a tooth pick drop by drop to all signs of a thread and let it soak laying lens up for half a day so hopefully some of this solvent would soak into the dreaded green goo.
Then, as gentle as I could, I gripped the lens holder with a pair of curved jaw slip joint pliers set to the right size. While holding the shutter, and not the camera body, with slow steady pressure and turning the lens holder unscrewed. Your range finder is likely screwed up as well with this old lube.
Scrape all the congealed old lubricating crap out with toothpicks, sewing needles, etc. I relube with silcone grease sold to lube Moen faucet valve cartridges
Recollimate the lens, and then start to hunt down the pinholes in your bellows. If it is an old ansco/afga I can almost guarantee you will find a few.