I got a couple screw samples from a Japanese company...don't remember what size at the moment...elsewhere, someone suggested just identifying as closely as I could...on such small screws, the European vs. Japanese thread differences won't make a difference.
They worked, I got the focus threads cleaned & relubed & cleaned the hazy lenses. I don't remember if I had any shutter problems & did anything. The focus was really wacked out...focused about 1/4" behind the film plane. I let it sit for a while and tonight, unscrewed the rear cell and reversed the rear element as a first retry attempt. It now focuses on a piece of paper in the film plane now...can't find a piece of ground glass or Magic tape at the moment.
So now I'm ready to try it out...but my film developing pace is obviously an obstacle...I guess I could pay a lab, but I dunno...maybe it's a good excuse to make time & space to develop the increasing number of rolls I decided I should do myself instead of paying a lab...when the film is fresh and I have confidence in a camera, maybe the convenience of a lab has merit. WHen prospects of results are slim...paying someone else adds insult to injury!
I put a bright LED inside the bellows in the dark & don't see any pinholes. I think the really old ones had better bellows than the newer Isolettes.
Cool thing about the really old ones is the dual format (4-1/2 x 6 cm & 6x6 cm). Secondary minor cool element is the black Trolitan (Bakelite cousin) top piece.