by Irish GTA » Mon Jun 26, 2017 8:57 am
The white nylon guide will be sitting on top of a similar one at the bottom of the glass as Clee stated. If you wind the window up fully, the upper guide will come with it. Then you can gently pull the glass outwards and poke in a tool to shift the upper nylon guide up to the top And hold / jam it up there. Then wind the window down and concentrate on lining up the hole in the door frame with thread in the moving window section. Check you have access to screw the screw in. Now lower the white nylon guide in place and replace the screw.
I think the standard screw is too short. The end thread was damaged by the screw being pulled out. This reduced the effective thread length and it was difficult to re-engage, plus pulled out again. That's why I used a screw 2 mm longer. It projects through, but does not foul on anything.
Also make sure everything is really clean and keep it that way. Dirt in the channel & built up on the guide causes it to stick. This puts a bending moment on the screw, distorts the thread in the metal window and pulls the screw out. The screw is really too small. A bigger one - even M4 would have enough clamp force to overcome the pull out force on it. The design was probably given to a young inexperienced graduate engineer in ~1982, who didn't appreciate the increased loads caused by use.