300CD rear window aluminum trim

[Beaucoll0]

I'm wondering if you might be able to give me some advice on a problem I'm having with my 1982 300CD ("Nadezhda," 148,000 mi). I did something pretty dumb, but I don't know enough to know exactly how dumb it was.

In an attempt to properly seat the aluminum trim pieces around the rear window of my coupe, I ended up removing them (pictured below). This was an impulsive decision that came at the end of a quarantine-inspired maintenance frenzy. Now I’m having trouble figuring out how to get them back on. It seems like I need a special tool to wedge the lip of the trim into the rubber, or that the entire window needs to be removed.

My main question: Is this a terrible unforced error that will require the labor of a professional to correct, or is there a way I can correctly reposition the aluminum pieces myself?

My secondary question: Can I drive around with the aluminum trim off, or will the window fall out (might be tempted to turn the hole into a B-17-style tail gunner position)? Pre-mistake, I assumed that these pieces were cosmetic, but on second thought, that doesn’t really jibe with MB’s 1970s design/engineering ethos.

Summary of problem I was trying to fix: At the junction between the two top aluminum pieces, the pieces were riding up out of the seal (pictured below). It looked wrong, and I was concerned that the seal was not seated properly. Then I took a look at photos of other coupes and noticed that none of them had the rubber curled up over the inside edge of the aluminum pieces, as mine did. So I assumed that someone had removed the glass at some point before I owned the car, and replaced the trim incorrectly.

This is my first post (cry for help, really) here, but I’ve been learning from this forum since I bought this car close to two years ago, knowing absolutely nothing about maintaining cars. The vibrant community of people who understand the non-monetary value of these cars and care about maintaining them for daily use is part of what convinced me that it was not a terrible idea to buy a car that is significantly older than I am. So thank you for that — would have made many more mistakes without you — and for any insight on this problem.

Beau

[Mike D]

The trim, gasket and windscreen are installed as a "one piece" unit.

The gasket is placed around the windscreen, the trim is inserted into the gasket and the entire assembly is "roped" into the aperture. No way, or at least I have never seen anyone do it successfully, to insert the trim into the installed windscreen.

Your thinking is correct. The trim acts as a lock to secure the glass into position.

You MIGHT get lucky and be able to remove the glass by CAREFULLY feeding the lip of the gasket over the body from the inside using a plastic trim tool but I doubt it.

More than likely you will end up replacing the gasket. I suggest, if you have never done this job before, taking it to a glass shop and have them do it. The windscreens on coupes are one of a kind and tend to be pricey. Replacing a broken one is a major expense.

Even worse news. By removing the trim you have probably bent it.