Why would the rear window drop down ( about 1/2 way gradually ) It is as if the support mechanism is broken This window has rarely been used Is it true that some of the support mechanism is plastic and prone to fail. Just had the transmission rebuilt and wiring harness replaced at 85 K miles. The wiring harness should have been a recall as everyone mentions it going bad something to do with biodegradeable insulation?? MB quality was misplaced in this series- a shame building too many to keep quality up. Thanks Al
This is a known problem with the W140...happened to both of my rear windows even though they were hardly used. The regulator assy has a critical part that's made of plastic, and it just breaks. The replacement part uses a metal piece.
I replaced both of mine myself, takes less than an hour per side. If I recall, the part costs +/- 150$USD from the stealership, I could look up the receipt if you need exact price. Aside from a screwdriver, you'll need a drill to drill out 3 big stainless rivets, and a big pop rivet gun to replace them. (I can't remember if the rivets came with the regulator assy, or if you have to ask for them separately...make sure you get them)
The hardest thing was to figure out how to get the door apart. I found directions on the net somewhere. One note...The first step is to pry the little "half-oval" shape piece of woodgrain plastic out of the door. Be careful !!! The woodgrain show surface is about half a mm larger than the backing plate behind it. Why you pry it up, make sure your tool is in far enough behind the part to pry against the backplate and not the little free edge of the show surface. If you don't, you'll end up cracking the show surface and replacing that part as well. I wasn't and managed to crack them both.
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