I have an '85 custom cruiser full size wagon and the passenger side front door window is loose and sitting at an angle in its frame. The little plastic guide in the upper rear corner is gone, and it seems like the glass itself is loose from where it attaches to the power window regulator-the front bottom corner of the glass is lower than the rear corner. What do I need to do to fix this?

 

Go to the HELP parts section of your local auto parts store.
They are black plastic clips that snap into the window track and through the hole in the glass.

https://www.dormanproducts.com/cgi-b...list=1386:98:0


As far as tightening the glass into the regulator goes.....
Remove the door panel and buy a small cheapo Hole saw. Roll the window up to a safe place to drill into the metal, and use the hole saw to make a hole big enough in the metal to slide a socket and extension in to tighten the bolts up.
Obviously, not too tight or you'll break the glass.

Then put the panel and everything back on.