Canon LTM Canon 50/1.4 LTM re-grease?

[ssmc]

Hi all,

I recently scored a virtually mint black/chrome LTM 50/1.4 The only thing "wrong" with it is that there's a little play in the focusing.

I assume (maybe naively - please correct me if I'm wrong) that this is due to the lubricant drying out over the last 55 years or so, leaving some clearance between the inner and outer threads (at least that's how I imagine it). Is this the usual cause of this problem?

My question is, how much disassembly is required to just clean and re-grease the focusing mechanism, and what tools do I need? Do I need a lens spanner or will correctly-sized screwdrivers be enough? How difficult/risky is it to try to disassemble a lens of this age? I don't need access to the innards of the optical cell; it's clean and clear apart from a small amount of dust and the diaphragm works smoothly.

Apologies if this has been covered elsewhere

TIA,
Scott

 

[Never Satisfied]

Hi Scott, my advice on this particular lens is don't do it! I have the same lens with the same porblem and it's not the grease in the hellicoid that causes it, otherwise the focus would be stiff and notchy, or abnormally loose.

From what I can gather, there is a longitudinal guide that runs from front to rear inside, it is the side clearence on this guide that causes the slight play, which is very annoying.

I've had a few goes at getting into it, without success.

Good luck, Andrew.

 

[ssmc]

Ah, that makes sense.

It also suggests a lot more disassembly would be required than I'm prepared to attempt.

Thanks!
Scott

 

[Bill58]

I'd never attempt to repair such a valuable lens myself. Get somebody competent to do a complete CLA.

 

[Bille]

I have just had one CLAd with the same issue and it was definitely more than just dried grease.

 

[ssmc]

Thanks for the replies - I think I will send it off for a pro to look at rather than risk it myself!

Scott

 

[SteveM]

From what I can gather, there is a longitudinal guide that runs from front to rear inside, it is the side clearence on this guide that causes the slight play, which is very

I've had this lens apart and agree that this is the most likely culprit. Re-greasing will not fix it. The small tongue that slides in the groove is held in place by the two tiny screws on the back flange of the lens. No disassembly of the helicoid is required. The tongue is brass and with very gentle tapping it can be flared out to fit more tightly in the groove. However, re-greasing will also be useful to these old lenses so a professional CLA would be useful. Aperture is often tight, and once relubed, the lens is much nicer to use.

I posted some photos of this lens disassembled somewhere in the repair forum if you do a search.

Steve

 

[Phil_F_NM]

This is the easiest lens to disassemble. You just remove the locking ring around the rear element and the whole optical module easily slides out of the focusing helicoid. After that, tighten up the two screws that hold in the axial guide.
Reassemble then get the rear locking ring down good and tight. In fact, you might just check the locking ring because this is sometimes the culprit of the loose feeling. You may just have to tighten down the ring and you'll be good to go.

Good luck!

Phil Forrest