One warning - You could be getting into the time frame when the optical unit was glued into the focusing mount. I really don't know for sure on yours.
Originally Posted by clayne
On my earlier 35 Summicron there is a retainer in the rear that holds the optical unit into the focusing mount. Take off the retainer and pull out the unit. Then, I believe, the rear will just unscrew and get what you need. I think the 6 element version just before yours was the same.
If yours isn't held together that way, you may still be able to unscrew the rear optical cell without disassembling the lens. Probably not much to get a grip on though (pieces of bicycle inner tube are handy grippers). If there is a single retainer slotted for a spanner in the rear, it will likely only get you the last element or cemented group, but sometimes is tight enough that the whole cell will unscrew.
If you don't like the situation when you look it over, Sherry Krauter is very good for this. Edit - Oops, I see that would not be convenient from your location.
If someone is more familiar with this particular lens, hopefully they'll speak up. I've only had that version in my possession for a couple weeks several years back.