Originally Posted by hilltime
That's Brett. Your comments are always well received. Sounds a bit more complicated than I had hoped for.
Thanks. Well, it might get involved, or not. Providing the helicals remain firmly secured to the focusing ring, removing the retaining rings for any optics, in itself, will not produce any drama. I've worked on a number of different CZJ lenses: both 58mm and 75mm Biotars; Tessars; Flektogons; Biometars; Pancolors; and probably a few more. But sadly, as yet not the 180mm Sonnar. I say "sadly", because I'd love one, myself.
Most of those as I alluded will dismantle in such a way that the optics can be separated from the focus module without having to split the helicals to get to them. But I learned the hard way when servicing my reasonably uncommon early 80mm Biometar in Praktina breech mount that sometimes the focus module connects with the optics in ways you don't anticipate. Yes, I got it all back together and working well, but it was a long night...
Also depending on the lens involved in some cases there may not be enough clearance for a spanner around the inside rear of a lens without first extending the helicals so far that they split. This gets you in the deep end immediately if you haven't been noting the precise positional relationship between the focus ring and helicals at the point they split. Obviously the helicals won't thread apart when the lens is fully assembled. But if you have already had to partially dismantle the lens by Eg removing its rear securing ring—if it has one—once the helicals screw past their keyway to the lens barrel, if they rotate with the focus ring, instead of being driven up and down the barrel by it, you're in all sorts of strife.
I would not be discouraged, if you are able to keep the focusing unit entirely complete and reach the optics you can get to, you may have a good result. If needed, post up some pics as you go along and I'll take a look.