Originally Posted by Rick76

The SLC is the opposite of the W116.
Clips on the front and trim in the rubber on the rear. Trim must be installed before installing window.

When inserting the trim in the rubber use a lubricant that will totally evaporate such as isopropyl alcohol. Leave it at least overnight so the alcohol evaporates completely. Anything you use to make the trim pop in the rubber will make it pop out when you try to install the assembly in the vehicle if any traces of it remain.

Pay particular attention to the corners that the trim is fully seated in the rubber. I've seen a lot of installations where the corners are not properly seated.

Never hit the trim with a rubber hammer as it will fracture the delicate aluminum anodized surface that will show up when in sunlight.

Check for any rust and repair. Mine had the paint cut through to bare metal where the factory workers had used a knife to cut the headliner where it wraps around the window opening. Rust in spots had progressed almost to where it would show up with the installed window.

And then there is the topic of sealer which seems to bring out a variety of different opinions.

When pulling the ropes starting at the bottom, the helper must push down as well as lightly pushing in as the window has a tendency to creep up causing it to be uncentered in the opening.

Are you using a new seal? From MB or aftermarket?

Where did you get the replacement window?