I have a Vivitar 28-85mm zoom for Nikon AI mount. The movable part of the barrel wobbles. I have made sure all of the visible set screws on the outside of the lens are tight, but there's still a wobble. Anyone have any suggestions?
I once had good results with disassembling a simple zoom lens and found that the guide pins for the inner lens tubes were all loose. See the former thread 'Don't be afraid of the zoom'. Also, check the repair article section for lens repair articles.
But I think most other zoom lenses are more complicated than the one I found. Check whether there are some adjustable rings or tubes around the rear lens. In this case it probably will be impossible to readjust it correctly with DIY methods.
