Re: Installing 68 door glass
Instructions are good, but I've never seen one that includes the measurements of exactly *where* to place the metal brackets at the bottom. I would take careful measurements off your old glass first. That's how I did mine when they worked loose. And they always work loose.
Also, I used some 3M epoxy, stuff is usually used to glue in newer windshields, that works. You'll want to allow it to set up for a day or so before putting back in the car. Also, pay attention to the angle that the lower bracket is installed to the glass. Get this wrong and the window is liable to "tip out" at the top, instead of in towards the rubber seals. BTDT.
It's worth mentioning that I've been through this several times with my Ranchero. Keep you eye out for '69 Ranchero glass. Ford finally got smart and used bolt on lower metal brackets. MUCH, much better than the glue on.
Hope this helps!
'68 Ranchero 500
'70 Cougar XR-7 Convertible
'98 Mustang GT Convertible