Nikon 35-70 f2.8 zoom focus shift

[Dez]

I have one of these excellent lenses, and although cosmetically it shows a lot of wear, the glass is great. It does have one annoying problem however. The zoom cam is somewhat loose. As a result there is a significant focus shift when moving the zoom ring in and out. This isn't the expected optical shift, the front group is loose internally and shifts with any motion of the zoom collar. The AF compensates for it, but I would like to fix it. Has anyone out there encountered and fixed this problem?

Cheers,
Dez

 

[Landshark]

Typical zoom lenses have slots in the sides of different tubes. These are the cams. Rollers attached to inner sections of tubing move along the cams to adjust the optical groups.
The rollers are nylon sleeves on a metal shaft and are held in place by screws.
So far, so good.
The wobble can be caused by Broken or cracked rollers or simply by loose screws.