I have had this car(1993 850) for 4 years now. Mechanically it has been great- but all the small stuff has broken. My latest saga is this. One day recently i was rolling down the drivers window and for no apparent reason the window came off of the track and got stuck. Fast forward- i went to Volvo and bought 2 green window pivots and put them in. that didn't work so i assumed the regulator was bad. I went to the junkyard and took a regulator off of a 97 850 and put it in. I greased the pivots and tried the window and it seemed to work ok . Today(5 days later) I was rolling down the window-yes you guessed- the same thing happened. Now what do i do? It is a good thing there wasn't a can of gas nearby . Can anyone tell me why this happens????????????? I have already replaced a lot of stupid little stuff on this car including the odometer gear. I am getting tired of fixing this car!

 

I own a 1995 850 GLT. I am going to have a similar porblem. My driver's window now makes a click sound as it reaches halfway down. It does not click at all going up. The click sounds like it comes from a 'gear tooth'. My temporary solution was to put a small piece of masking tape on the door where it clicks. I will not lower it beyond that mark until I find and fix the problem.
I will not buy any parts until I have searched the internet -- websites like this and called a mechanic at a Volvo dealer and discussed it. I will get as fully informed from people who know before I reach for my wallet. I do not yet know the solution to your problem or mine.
The mechanics at the Volvo dealership are nice, but they are at work and have other things to do. I respect that. I know I am asking for a favor so I prepare one or two quick questions before I call. I keep the call short and thank them sincerely and with great appreciation ! Try it.

 

Check the window track on the back side of the door. There is a screw with a finish washer that holds it in place. To get to it you need to remove the door latch which is a bit of a pain.

The reason I say this is while I was replacing my door latch I noticed that the lower tab that holds the track in place was broken and the track was only held at the top. I removed it and saw that this tab had been welded once before and the new weld broke too. Just an idea but who knows? good luck.

 

I don't think it is anything other then what was mentioned above. I had this same issue on my 240 and I had to bend the track to get the window to go up and down correctly. It really does sound like it is falling off the track for sure.