wierd window problem

Guys,
the rear driver side window on my 300E seems to close 3/4 of the way but never all the way shut. I've tried numerious times but no luck. It will go down all the way and come back up as well but simply stops at 3/4. If it wasnt working at all I would've suspected the regulator. What do u think could be causing this wierd problem ? both the switches, console and the one on the door do the same exact thing.
any ideas ?
thanks. !

[G-Benz]

You have a broken track holder on your window regulator. This is the most common failure among 300E owners as these age. I had replaced the regulators on both rear doors within a year of each other some time ago.

I believe the part is obtainable for a couple of dollars. Otherwise, depending on how much playing with the window you've already done, you may have buggered up the cable mechanism enough to warrant a new assembly ($140+).

Either way, you need to remove the door panel to get to the offending part. It's about an hour (or more if it's your first time) to do the R&R...