w124 window won't roll up
 

Driver side front window stops about 5-6mm from the top, just inside the window seal. It startled me at first because I heard a loud popping/cracking sound all of a sudden, I assume this is a mechanism to protect the gear teeth not the teeth being torn to bits each time I roll up the window?

I checked threads and the door itself looks ok, nothing in the track that I can see to obstruct it. So, does this mean my regulator is bent/broken and will not allow the window to go fully up? Or maybe it is can be tightened up or adjusted? The window is not loose, there is only a little bit of play when it is rolled down.

I'd like your opinion before I take the door apart; this is old car and I risk breaking some plastic bit taking the door off (I was lucky the first time, when replacing the door check).

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'94 E420, 275,000 miles

Only way to find out is to open it up... you're going to have to open it anyway to fix the problem.

I had the same issue, turned out to be a plastic clip on the regulator, it had snapped and swiveled down so the window would still operate but stopped an inch or two from the top. I would recommend taking a look at the regulator, they are pretty easy to get out (easier than the w126 jaws type for sure)

A hot glue gun helps much of the time in repairing any door panel clips that break off.