Photoclubalpha

Original version.
Screw drive doesn't have a washer on it and keeps popping out when you AF the lens
Any ideas?
Bar acquiring a part from a dud lens (if anyone has one I'd be interested to hear from you)
Seems a shame to de-commission the lens just because of this.

Wonder if that just needs a retaining ring? The only lenses I had apart had a plate held by 2 screws that held that shaft in place because the shaft was bigger than the opening in the plate. is there nothing loose and rattling around inside your lens?

Edit: That part is called a coupler and it's similar to the one on my 28-135. it uses an E ring inside on that slot to retain the part. if the ring is missing then any mill supply should be able to measure the slot and provide one for you for pennies.

Look at Pete Ganzels site and in his disassembly of his 28-135 it shows an exploded view of the lens and the parts it needs

Thanks for the reply. I can't see anything floating around inside the lens. The gears are mashing a bit and it's quite jerky so I suspect some issues elsewhere too.
I'll probably hold onto it as a spare parts lens, and look for another 28-85mm

Just an update. I found detailed information about the lens here:

http://allphotolenses.com/public/files/ ... 40e9f0.pdf

The same site also has more pdf files some with service manuals.
I managed to get a (believe it or not) "as new" copy off ebay boxed it's absolutely spotless in terms of optics and body.
Interestingly the serial number is much later than the first copy.

I'll keep the first 28-85mm as a spare parts lens.

Barry, nice link and thanks. I already bookmarked it.