Replaced the driver’s side regulator on my 1992 745. The unit was secured by rivets. I don’t remember what size drill bit I used but the rivets are soft and if you take it slow (drill speed) it‘s no problem. I used nuts and bolts to secure the replacement regulator (I think I used locking nuts – the kind with nylon inserts). Just use the shortest bolt possible and there’ll be enough clearance for the regulator to move. As Dan said, remove the window retaining clips and then the window. By lowering the window about halfway, you’ll have access to the clips.

If I remember correctly, you’ll then want to lower the regulator to the lowest position (the position where the window would be all the way down) and then remove screws/rivets. The unit can then be removed through the lowest front opening on the inside of the door.

Good Luck,
Michael
Melbourne, Fla

1985 740 460k (original motor)
1988 780 Coupe V6 190k
1989 780 Coupe V6 149k (parts car)
1992 745 197k