I see no one has replied. I can't offer much help either but I thought I would at least reply to the lonely post. I can tell you I was not successful at attempting a similar repair on a Zorki 4. I actually purchased 3 of them. One functions, one I was able too warm, work with, and apply just a tiny bit of break free oil to the mechanisms and it now works at all speeds except 1 second. The second curtain doesn't shut for some reason at the 1 second setting. The last one had issues. Initially the slow speeds did not work and the curtain ribbons dis-attached themselves nicely after I had it for a day. It was $30 and I got half back on a refund and kept it to learn. What I learned was I can't take apart the slow speed mechanism and expect it to function normally again..... Never could get it right. For now I'm limiting my excursions into Barnack repair to rangefinder and curtain spring adjustments. Unfortunately my recommendation is to send it off for repair. I have opted just to keep my $30 Zorkis as is and not fork over the money for repair yet. They are working good enough. For the cost of a good CLA on the Zorkis from a reputable repair person I got my first Barnack Leica, a IIIc, with a recent CLA already. I still use my Zorkis. My '61 has proven to be very reliable and I don't ever need 1 sec anyway.