M Roadster Rear Window Replacement - Help

[Thartigan]

I'm in the midst of trying to install a new rear plastic window on my '98 M Roadster, which I acquired in March '23. Like others, I have had the same failure in my right and left upper corners pulling away. Prior ownership did glue those areas, which bided some time, but that too has failed. Car sat in storage for 22/yrs before I acquired, accumulating only 3K miles during that time, but was maintained and well cared for based on its' condition. It now has 19K miles (14K 1st owner) and the top is still in very good condition, so hate to replace the whole when just the window needs replacement.

However, this has been an exercise of extreme frustration. I purchased a window from Z3Window.com and it seems to be very well made. Matches up size-wise to my current window. The install can't get off of first base, though.

After the zipper slide broke and finding a new one, I've gotten pretty proficient at getting both ends started and zipping closed towards the first corner - lower right side. Either 2~3 inches before the corner, or while trying to make the bend, the zip separates requiring going back over the open portion. Sometimes it closes and I can move forward, most times I need to restart from the beginning. Even if I can move forward, by the time I turn the first corner, it is separated again. I do have an extra set of hands, my wife who has been quite patient and useful, but together we don't have a solve for this.

Any words of wisdom or tricks of the trade that I can lean on would be greatly appreciated. I've exhausted YouTube videos, but will say Meca Upholstery did a very good video, the best and most informative, cheers to him. However, no one addresses my issue specifically, zipper separating or not closing, and I am at wits end.

Pics are prior to removal of window. I'm located in Bluffton, SC (Hilton Head / Savannah, GA area) and would also appreciate any local contacts / biz that have experience with installation.

Thanks in advance.

 

[Shelly]

 

[Althulas]

Hi and welcome from me.

Have you tried having the top partially open to relieve the tension?

Is the top tightish to close? Maybe the fabric of the roof has shrunk a little. You could try wetting the roof to allow it to stretch a little but do have the roof partially open a bit while zipping the window in.

Do the teeth still look decent after these repeated separations? Just wondering if any of the teeth got damaged.

As a last desperate measure you could suture around each corner after zipping as extra security but this should not be needed and I don’t know if anyone else has tried this.

 

[Duncodin]

I needed to take my window out and then when I wanted to refit it I couldn't find the original slider so searched round to find one that fitted. It really did feel like it was the right sized slider but I get the impression the one I found was a fraction, just a tiny bit, too big.

Is the OEM slider a standard size? Sliders are really cheap but I just seen somebody on ebay flogging z3 ones for a crazy high price 10er

Anyway, in places it didn't close properly and all that fiddling and tugging I've ripped a lot of the stitching out so my roof is trash.

 

[Ian&Sue]

I've no personal experience of doing this job but sure I've read somewhere that it helps to stitch the zip together as you work your way around. Good luck. Ian.

 

[NZ00Z3]

Try releasing the top tension by opening the top and placing a 4" to 5" box in the opening to hold the top open slightly.

 

[paynter]

I'm in the midst of trying to install a new rear plastic window on my '98 M Roadster, which I acquired in March '23. Like others, I have had the same failure in my right and left upper corners pulling away. Prior ownership did glue those areas, which bided some time, but that too has failed. Car sat in storage for 22/yrs before I acquired, accumulating only 3K miles during that time, but was maintained and well cared for based on its' condition. It now has 19K miles (14K 1st owner) and the top is still in very good condition, so hate to replace the whole when just the window needs replacement.

However, this has been an exercise of extreme frustration. I purchased a window from Z3Window.com and it seems to be very well made. Matches up size-wise to my current window. The install can't get off of first base, though.

After the zipper slide broke and finding a new one, I've gotten pretty proficient at getting both ends started and zipping closed towards the first corner - lower right side. Either 2~3 inches before the corner, or while trying to make the bend, the zip separates requiring going back over the open portion. Sometimes it closes and I can move forward, most times I need to restart from the beginning. Even if I can move forward, by the time I turn the first corner, it is separated again. I do have an extra set of hands, my wife who has been quite patient and useful, but together we don't have a solve for this.

Any words of wisdom or tricks of the trade that I can lean on would be greatly appreciated. I've exhausted YouTube videos, but will say Meca Upholstery did a very good video, the best and most informative, cheers to him. However, no one addresses my issue specifically, zipper separating or not closing, and I am at wits end.

Pics are prior to removal of window. I'm located in Bluffton, SC (Hilton Head / Savannah, GA area) and would also appreciate any local contacts / biz that have experience with installation.

Thanks in advance.

I realize this is an older post but I feel your pain on this install may be for future readers
I worked for 6 hours on the 1st window cheap rolled up in a ball unit was so frustrated
decided to look for another window, was concerned that the zipper was messed up so bought another cheap one from different mfg.
it zipped up in 30 min. or less almost 1st try zipper was smooth, went around corners without any issues