How to restore smooth focus to stiff ltm lenses

[caymanlawyer]

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I have my father's LTM lenses (90 Elmar and 35mm Summaron f3,5), which have been unused for 50 years. The focusing rings had jammed solid on infinity, but after applying pressure for a bit I have been able to get them to move. The Elmar is relatively smooth now but the summaron is very hard to mover still. I have tried moving them back and forth but they are still nothing like my red scale 50 elmar. Would it work to apply a small amount of grease or oil to the brass base to get them back as they should be, or is this not recommended?  If anyone has dealt with this problem before and has any tips I would b e super grateful to hear them. Thanks. 

[zeitz]

Oil is definitely wrong.  Any new grease would have to be optical helicoid grease.  But to get the lenses to work like Leica lenses, they need to be disassembled and the old hardened grease needs to be removed.  I think you would get the best result sending the lenses for cleaning and lubrication.

[caymanlawyer]

I think you are right. I expect that they will probably be a bit fogged as well. I have just shot a test roll but haven't developed it yet. 

[oldwino]

Get them all cleaned up, and lubricated, and they’ll work great for another 50-60-70 years. 

[spydrxx]

If you're so inclined, in the meanwhile, you can apply 1 drop of lighter fluid to the helicoid to loosen the congealed grease, and then work the focus back and forth. A CLA is the best answer, but in a pinch......

[250swb]

I like the idea of trying lighter fluid as said by @spydrxx , it may work or it may not, but it can't make the situation any worse by using a couple of drops. What lighter fluid can do is cause false hope, it frees up the helicoid for a day but as it evaporates the old grease goes back to being sticky.