OK. New to the site and not sure I’ve done this right. If I did, there will be an active link and three photos here.
Although the original thread is a year old, I’m thinking the problem with the windows going up too high in the early SLK’s is pretty common, and others will come across this thread in their search for solutions. So trying to provide some additional info for those folks. The link below (borrowed from Jbanks15) is to a set of YouTube videos on common DIY repairs. One is on how to remove the door panel - which is best done with some knowledge of where the fasteners are, etc.
I’ve also attached three photos of my recent repair. As others indicated, the problem is often (and was in my case) caused by a pair of metal “brackets” that are glued to the window glass falling off. On taking the panel off, if this is your issue, you’ll find one or both of the brackets lying in the bottom of the door frame. Take the main door speaker off. Three machine screws and a wire connector. With the window all the way down, you’ll see the place where the brackets were installed. Glue residue and grime outline on the glass. Clean that all up, buff up the brackets on a wire wheel if you have one. Opinions vary on best adhesive. I like JB Weld two part epoxy and it worked for me. One bracket is glued to the “outside” of the glass with the horizontal leg facing to the inside. Position it just forward of the “corner” where the bottom edge of glass angles slightly upward and snug it up so the horizontal leg is tight to the bottom edge of glass. Figure out a way to keep it in position while epoxy sets. Once glue has set on that one, take the second and glue it to the INSIDE of the window glass, with the horizontal leg sitting on TOP of the horizontal leg of the first bracket. That’s it! Once epoxy has had time to set, check that feels solid and then raise your window and see how it fits against the seals with the top up. In my case it was now perfect. If it isn’t, others have posted how-to’s on window adjustment by loosening screws in the door and shifting in slotted mounting holes. I didn’t have to do that so won’t comment. In my case, since only the top bracket had fallen off, the driver’s door was only rising a bit too high. On the passenger side, though, BOTH brackets had fallen off and that window raised way too high. I had to bump the window open a bit just to get the door closed.
Three pics I attached show the entire driver’s door with the panel off and speaker removed (round hole near front of door). Other two show, first, close up of the bottom of the glass and the location of the first bracket installed. Truth be told, in my case, that bracket was still in place - so it was pretty clear to me how the other was supposed to mount. Last photo shows that second bracket epoxied back in place. (The surfaces to be glued were buffed to shiny metal.)