Stiff Focus, LTM Elmar 5cm 3.5

I assume it is due to dry lubricant +dirt in the screw. Can this be corrected by cleaning and lubricating the

screw without disassembling the lens? Obviously, disassembly would be ideal. What are the odds of an

inexperienced person such as myself unleashing a whole can of whup-ass on myself and the lens if I attempted it?

<p>Don't know what are the odds, but do know that the can is bloody enormous.</p>

<p>One of the difficulties is obtaining the proper lubricant....I did it years ago to a Summaron, and it eased the situation, but a year later when it went in for a CLA the difference was like night & day. Get it done by a seasoned pro and you shouldn't have to worry about it for 10-20 years.</p>

<p>Don, that lens is quite easy to unscrew the <strong>close focus stop</strong>, which then allows you to proceed to separate the mount from the focus helical. Just note a reference point as to where the mount released itself from the lens body.<br>

Clean away all of the contaminated & failed lubricant from the two surfaces with solvent.<br>

Only then can you apply the lubricant of your choice. (How heavy the focus feel depends on how thick your choice of grease is)</p>

<p>Have fun, with this model Leica lens it's pretty tough to screw up this particular stage of a C L A.</p>

Thanks for your replies, and especially Guy for the confidence boost. Can you recommend a lubricant? I prefer a bit of 'feedback' in the feel.

<p>Don, you can experiment with whatever greases you have on hand; <strong>you're safe with this lens</strong>.<br /> This focus helical is basically external to the lens holding cartridge. As soon as you remove the lens from the body, any long term out-gassing is dissipated. FYI: There are wonderful <strong>synthetic</strong> greases out there in the automobile world.</p>

<p>Hi Don and Gus,<br>

I have just aquired a similar 1954 red-scale 5cm Elmar with a Valoy II. It is in absolutely mint condition with the special VALOO focussing hood, but the grease has hardened from being used in an enlarger. Gus, are there any particular brands of synthetic greases you would recommend?</p>

 

<p>I have used pure silicone grease on many lens helicoids, it gives a nice smooth feeling when focussing.<br>

However, regreasing means disassembling in most cases. You may try to give a few drops of lighter fluid on the visible parts of the helicoid, but it is not sure that this will be a permanent fix. If you apply some droplets of non-hardening oil after that, it will probably last longer.</p>

 

<p><em><strong>Winfried</strong></em>, that pure silicone grease is meant for sealing rubber surfaces and waterproofing. It is very reactive to temperature and inaction. It changes viscosity way too much...</p>

<p><em><strong>Peter</strong></em>, these type of automotive greases have set standards and specifications to meet.<br>

Many are even military specification approved.<br>

So many good brands, just read the labels. (Temperature range and spec codes) </p>

<p><strong>Let's not forget</strong>, all of this advise is in regards to a very simple <strong>external focus</strong> lens model. Internal helicals require a lot more thought, specificity and care. (Out-gas fuming is the main concern)</p>

<p>I acquired a 5cm Elmar which was completely seized when it arrived. I warmed it very gently and eventually got the focus moving enough to extend the focussing coil to the point I could use a cotton bud dipped in meths and a toothpick to scrape out the accumulated grease. Gradually the focus eased up to the point where it worked fine and has required no further attention since.</p>