Zeiss Flektogon aperture issue

[Analogski]

Hi,

I have a weird issue with the aperture blades in my Flekrogon lens (P6 mount). When I rutn the aperture ring, there is no problem, but when I push the little pin in the back of the lens in, and let ho, the aperture blades stay open. With a bit of pushing in and out the blades will move again, but it's strange. Moreso because the blades work perfectly when turning the ring. There is no oil or other stuff visible on the blades.

What could be the problem? And the solution?

Thanks!

 

[loccdor]

If there's no oil on the blades then my best guess is dried up grease and dirt on the springs and levers linked to the aperture. You may be able to remove some parts on the rear to access those.

When you let go of the aperture pin, does the pin spring back strongly, even when the blades don't move? I had a Mir-26B 45mm f/3.5 with an aperture pin that was unreliable. I sent it for CLA, the problem returned after a few years.