Canon 85mm black: Dismantle and relube?

[sanmich]

Hi All

I received my canon 85mm f1.9 black. A beauty, and for what I have seen, very sharp.
The focusing is a bit sticky and I would like to relube it.
Would someone know how to dismantle the lens?
FWIW, I had a look to other long canon lens:
For both the canon 100mm black and the 135mm silver, you just have to unscrew the whole front block, aperture ring included.
But it doesn't seem to work for my 85, nor for a B/C 100mm.
I know it may be stuck after 50 years or so but I don't want to force anything.

Any idea?

Thanks!

 

[kurotama]

Hello sanmich,
I got a 85/1.9 silver with sticky focus as well. Its a very sharp lens and l like it a lot.

What I did was that I went from the rear-end of the lens and dropped a few dots of lighter fluid/silicone oil mixture with a syringe, onto the end of the focusing thread. You can see the end of the thread at closest focus by looking into the rear end with a small flashlight. So target the thread and carefully drop small amount of oil mixture to avoid the rear lens element. After that, wiggling the focus for a few roundtrips will give you a looser focusing feel.

It worked on my Canon 135 and 100/3.5 so you may try the same for B/C 100mm.