We have a leak on the passenger side of our 2003 430 Cabriolet. Driver's side is leak-free and seat's well. I checked the mating of the front and rear windows and found the rear window on the passenger side rises about 5/16 to 3/8 inch higher than the drivers side rear window. This causes the front edge of the rear window to also be too far forward, so the passenger front door window ends up overlapping the glass of the rear window at the top, instead of seating on the rubber weather strip. I'll try to attach two photos of each side to show the difference.

After reading some threads, I've concluded that I have a broken stop on that rear right side window, and have ordered one from autohaus. It seems to me that its either that, or the front door window is misaligned, but since I measured both rear windows extended height and confirmed that the misaligned one is higher than the non-leaking driver's side, I think I've identified the issue. Of course, I haven't opened the inside of the window mechanism yet to confirm it visually.

This is the clip I've ordered. https://www.autohausaz.com/pn/MB-2086730312

Any comments from owners with experience on this? I had hoped it was a reset problem but after putting the roof down and seeing the misalignment, and doing the reading, it seems to fit the idea that the "stop"is either broken or worn on that right passenger side. The window overlap means the vertical weather strip doesn't work to seal it, and also the back window pushes the roof weatherstrip up too high and stops the front window from seating properly.


Rear window is too high.


Driver's side aligned properly, and rear window height is proper.

 

If you remove the chrome trim plate above the door latch on the door, then peel back the rubber Gasket you'll see a black plastic block, mounted on a bracket, that the back edge of the glass runs on. You could try adjusting this upwards slightly to kick the back end of the door glass upwards and forwards.

 

Thanks for that.

I now have the part, and last night I went on eBay and found a listing for a right rear quarter window (w208) that has pictures that help. You can see the bracket in the pictures and it gives me an idea of what I'm going to be looking to do. I'll be interested to find if the actual bracket has failed at the plastic joint, or if somehow the adjustment has just moved over time. Seems it should be one or the other. In any case, I have the new stop bracket and it was only $15, so not a great waste if I don't need a new one.



Yellow line shows bolt holding the stop. It's in a slot so it looks to be "adjustable".

The small aluminum square is at the top and is the "stop" bracket. If you enlarge a bit you can see that the tip of it is black plastic.

 

So, I was able to install the new window stop on the passenger rear window, and adjusted it until the rear window pretty much lines up with the front window the way it does on the driver's side. Here is a picture of the alignment now with both windows all the way up.....a big difference compared with the first picture in this thread of the mis-alignment caused by the broken window stop.




Windows properly aligned after replacing broken rear window stop.

Here is a picture of the new window stop and the old one which had the plastic top part of it break. It was still attached to the rest of the stop when I removed it, but was just hanging barely attached, and not doing the job of stopping the window travel



New one at the bottom, with the existing torx bolt inserted.

The process took me a while.

To remove the window stop, you have to remove the side panel in the back seat, and to do that, you have to remove the rear seat bottom, the rear seatback, and then the side panel. I used the videos online for guidance. The side panel requires removing a phillips head screw which is under the escutcheon for the windscreen, and getting that out without breaking it was a bit tricky. You need a set of picks, and hook into the hole on the tab and pull it inward to get enough release to get that side partly up. Then you do the same on the other side, and you can get to the screw.

Once the area below the rear window is exposed by removing the panel, you can easily see the bolt that holds the window stop. To access the stop bracket itself, I had to remove the INSIDE weather stripping that is just a rubber channel over some aluminum. That came off easily. Once that was off, I used a couple of wood shims to push the window to the side to have a little more room to work. It's a very tight space. I thought I would have to remove the metal trim on the outside body near the window, but that was not the case, and that was good.

I used some magnetic strips and a finder magnet tool to remove the broken stop bracket. I taped up the torx tool, and held the finder magnet next to that, while simultaneously putting a thin, very strong magnetic strip down where the window stop was located so that it couldn't fall down into the mechanism. That was the relatively easy part.

After the old one came out, the problem was how to get the new one down into the window area and be able to get the bolt threaded into it from the inside of the door. This was a a serious problem since I didn't want to drop either the bolt or the bracket into the door. Here's what I did:

1. To avoid losing the window stop down into the mechanism, I took some 6 lb test monofilament fishing line I had and tied a tight loop around the stop bracket. This helped quite a bit as I dropped it three times into the mechanism, but was able to just pull it back up each time.

2. I experimented with various ways of attaching the bracket to something to position it behind the slot where the bolt comes through. (Its not possible to get your fingers into the small space.) I tried some aluminum stock and tape, and I tried using some long needle nose pliers to hold it. Those didn't work because I couldn't position it accurately and hold it against the bolt to get it to thread. A paint stick and chewing gum might have worked, but I didn't have those.

3. I solved that problem by deciding that I was making a mistake trying to hold the bracket upright during the process, which meant I was gripping it sideways on the plastic part, which didn't give me enough control. So I turned it 90 degrees clockwise from upright and was able to get a good strong pinch on the metal part that allowed me to get it threaded using the needle nosed pliers. After getting it threaded, I was able to rotate it upright, and loosley tighten it in roughly the old position.

4. Leaving it only loosely tightened, I put the windows up so that I could get the back window properly aligned at the same height as the front. Once I got that height right, I used the torx head driver on the bolt and made sure to slide the stop down so that it was actually stopping the window at that position. Then I tightened the bolt and tested the stopping power with a couple of down and up cycles of the rear window.

5. I looked around for a tutorial on how to replace the side trim to get the clips lined up right, but couldn't find one. I just reversed what I did to remove it and it worked out ok.