M mount Elmar 2.8 felt bushing

[davidnewtonguitars]

Has anyone adjusted the sliding bushing on the M-mount Elmar 50 f2.8?
The lens slides out too easily from its collapsed position. There are 2 screws on a cover plate on the rear/fixed portion of the lens, is the bushing behind that cover plate? Can I slide a bit of "packing" around the bushing and stiffen it up?
I've never seen a service video on the rear/fixed portion.

 

[davidnewtonguitars]

I have a partial answer to my own question.
I opened up what is just a cover plate, and there is no felt seal around the sliding barrel. It just slides thru a brass or steel carrier. I don't think there is any adjustment.

 

[helen.HH]

I have an M mount 50 2.8 v1
but I have the opposite problem ... Aperture ring turning smooth, focusing smooth
BUT my lens is solid tight with re : to collapsing in & out, needs abitof muscle

 

[davidnewtonguitars]

That would be an easy repair, first some Ronsonol, then some helicoid grease on the barrel. "Wipe on, wipe off."