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      07-02-2018, 06:57 PM   #1
dusty.brown
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E88 Convertible Rear Window (detaching the fabric)

I had this problem on my 2008. After ten years, the rear window glue failed along the bottom edge. After some searching, I kept seeing people do this the hard way. It seems no one tried detaching the fabric top. It takes 5 minutes and no tools.

1) The window sags (and rattles) because the glue has failed.
2) This problem is exacerbated by the tension pulling the fabric away from the lower edge of the rear window.

Trying to fix #1 without taking the tension off the fabric (#2) is a bad way to do this. I cannot imagine good results by gluing fabric when it is under tension. I see people posting utube videos with all kinds of clamps and tape.

Steps
1. put the top in the halfway up position so that the rear bow-shaped bracket is straight up in the air. (Note: when the retained power goes off after a few minutes, the top will fall limp. You may wish to have the car running.)
2. Pull the weather strip off and away by hand. It sits in a grooved channel.
3. On each side of the window is a small round plastic retainer (push it through) and a defroster wire (pull apart) that need to be removed.
4. Grab and pull hard on the fabric lip that runs along the rear bow, starting at either edge working towards the middle. It has a plastic retainer strip that sits in a grooved channel with hidden metal clips.
5. Now that the entire back section is free from the rear bow bracket, you can return the top to the closed position and clean up the glue with a razor blade.
6. Reglue without any tension.


Last note: In addition to the glue separating from the window, the glue holding the neatly folded fabric edge also failed. This is difficult to see and difficult to solve if you do not take the tension off the rear fabric. Both of these issues result in window sag.
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Last edited by dusty.brown; 07-02-2018 at 07:02 PM..
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      09-13-2019, 06:00 AM   #2
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Hello! i have the same problem with my 120 cabrio. May i ask what kind of glue did you use?
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      08-10-2020, 04:20 PM   #3
awns729
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How did this perform over time for you? I'm having the same issue.
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      09-01-2020, 11:12 AM   #4
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I didn’t do a DIY fix, I’ve taken mine to a convertible top place for two issues. But I think this is the stuff most places tend to recommend: https://www.amazon.com/3M-08609-Wind...ct_top?ie=UTF8

First issue: Was 3 or so years ago now. The fabric was detaching below the window, as noted in the thread. Wasnt exactly a showroom finish, but its still holding fast, several years later. My car also lives outside (no garage), and has snow on it over the winter, etc. So, that fix was pretty badass. Dont recall the cost though.

Second issue: This summer the rest of the adhesive was letting go around the top and sides (arg!), brought it to another place more local, and he sealed it back up. Thus far, its been holding up well. Cost me $200.

Unfortunately, neither of these guys were particularly forthcoming in HOW they got it to stay, but my point is - if you can find a local convertible specialty place, they may be willing to help and it might hold on for you for several years.
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      09-01-2020, 11:16 AM   #5
awns729
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Quote:
Originally Posted by Fantastipotamus View Post
I didn’t do a DIY fix, I’ve taken mine to a convertible top place for two issues. But I think this is the stuff most places tend to recommend: https://www.amazon.com/3M-08609-Wind...ct_top?ie=UTF8

First issue: Was 3 or so years ago now. The fabric was detaching below the window, as noted in the thread. Wasnt exactly a showroom finish, but its still holding fast, several years later. My car also lives outside (no garage), and has snow on it over the winter, etc. So, that fix was pretty badass. Dont recall the cost though.

Second issue: This summer the rest of the adhesive was letting go around the top and sides (arg!), brought it to another place more local, and he sealed it back up. Thus far, its been holding up well. Cost me $200.

Unfortunately, neither of these guys were particularly forthcoming in HOW they got it to stay, but my point is - if you can find a local convertible specialty place, they may be willing to help and it might hold on for you for several years.
I called one with good reviews and since my entire window has detached, he's only willing to replace the full top at $2100 since he's not confident a $350 reglue will hold once I try to put the top down. I think it will based on my reading here, so I'm left either finding another shop or DIY.

I believe these clamps (or similar) are the other missing piece to getting it to hold: https://www.amazon.com/Sealey-Suctio...8976968&sr=8-7

And then you complete the gluing process section by section.
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      09-01-2020, 03:43 PM   #6
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Quote:
Originally Posted by awns729 View Post
I called one with good reviews and since my entire window has detached, he's only willing to replace the full top at $2100 since he's not confident a $350 reglue will hold once I try to put the top down. I think it will based on my reading here, so I'm left either finding another shop or DIY.

I believe these clamps (or similar) are the other missing piece to getting it to hold: https://www.amazon.com/Sealey-Suctio...8976968&sr=8-7

And then you complete the gluing process section by section.
The 3M adhesive is really strong stuff and seems to be holding up well enough for my liking. It's waterproof, which is the most important thing to me. Definitely not a showroom finish, but it passes the 5 foot test since the adhesive is also black like the top. I also drive with the top down around 95% of the time, and the car is garaged in the winter, so no snow testing here.

Try to get the top fabric really tight/taught with those suction clamps. I didn't detach the top like the OP, but I can see how that would make the job much easier and cleaner. I used quite a few nitrile gloves in the process. Good luck!
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      09-01-2020, 03:56 PM   #7
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Quote:
Originally Posted by c0bra View Post
The 3M adhesive is really strong stuff and seems to be holding up well enough for my liking. It's waterproof, which is the most important thing to me. Definitely not a showroom finish, but it passes the 5 foot test since the adhesive is also black like the top. I also drive with the top down around 95% of the time, and the car is garaged in the winter, so no snow testing here.

Try to get the top fabric really tight/taught with those suction clamps. I didn't detach the top like the OP, but I can see how that would make the job much easier and cleaner. I used quite a few nitrile gloves in the process. Good luck!
Yeah, I'm hoping it's as easy at it sounds. I'm terrified of pulling the top apart and getting it stuck partially off and not being able to put it back on!
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      09-02-2020, 07:13 PM   #8
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Quote:
Originally Posted by awns729 View Post
I called one with good reviews and since my entire window has detached, he's only willing to replace the full top at $2100 since he's not confident a $350 reglue will hold once I try to put the top down. I think it will based on my reading here, so I'm left either finding another shop or DIY.

I believe these clamps (or similar) are the other missing piece to getting it to hold: https://www.amazon.com/Sealey-Suctio...8976968&sr=8-7

And then you complete the gluing process section by section.
When I was (briefly) considering a DIY job on my second issue, I also had those same clamps in my Amazon cart. IIRC, the video suggested a double order of them, so you can put them really close together.

Personally, I would probably give the $350 pro job a try, understanding it may fail fairly soon (and provided he’s willing to actually do it). I think it would hold up better than he thinks, provided he doesn't tank the job since he wanted to sell you a top and you didn't bite on it.

My window (as mentioned) has now been fully sealed and is doing fine. Not winning any beauty contests, but neither am I!
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      09-02-2020, 08:19 PM   #9
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Quote:
Originally Posted by Fantastipotamus View Post
When I was (briefly) considering a DIY job on my second issue, I also had those same clamps in my Amazon cart. IIRC, the video suggested a double order of them, so you can put them really close together.

Personally, I would probably give the $350 pro job a try, understanding it may fail fairly soon (and provided he’s willing to actually do it). I think it would hold up better than he thinks, provided he doesn't tank the job since he wanted to sell you a top and you didn't bite on it.

My window (as mentioned) has now been fully sealed and is doing fine. Not winning any beauty contests, but neither am I!
I asked a number of times on the phone. He's basically unwilling. I agree - people doubling up on clamps and DIYing have all reported back good results as far as I can tell.

If I can't easily find another reasonable shop, I might just tackle it myself since work is quiet these days and I have the time. Seems like under a day's work to repair.
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      10-06-2020, 10:18 AM   #10
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I had to do this fix last year when the rear glass separated from the fabric along the bottom and up one side. I scraped away as much of the old adhesive as possible and took the tension off the fabric by propping the roof open with a basketball and some towels under the back (before it closed itself under gravity).
Then I used those clamps and glue mentioned above (3M Window Weld) which, I have to say, is amazing stuff. I also used those free paint stirring sticks to try to spread out the pressure from the clamps. I also used a tiny can of 3M primer that you put on first, don't know why but I read it somewhere in another thread about this.
This is my third attempt at fixing this and while other glues held for a couple of months, this stuff has held for over a year.
One issue I do have is that when I took the clamps off I noticed that there was a small kink in the fabric at the lower left corner of the window. Think of it as too much fabric kind of bunched up in a small ridge. Well, with opening and closing the roof that ridge has frayed.... :-( It's not terrible but I can see it and it will only get worse I suspect.
Back to the glue. Once it has cured fully you can cut it with a razor blade to tidy it up. I'm not entirely satisfied with the look but it worked :-) However, I still have the rattle if I close the roof, but only for the first mile or two then something settles into place and it goes away. Overall, happy with the results, just wish I noticed that kink sooner.
There's a place I found online that sells these roof covers for $1000 but I was unable to find a DIY and didn't want to tackle this myself.....I have enough issues....cam ledge for example. N54 life I guess.
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      10-28-2020, 02:34 PM   #11
awns729
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Just about to take the clamps off tonight. I did the top half on Sunday night (my entire glass fell out), and the bottom half yesterday afternoon. It's humid and in the mid 50s here, so it sounds like it should be cured about now based on the spec PDF for window weld. The top half seems to be holding well. Mandinca and @dusty.brown your instructions were very helpful - thanks!

If anyone wants to purchase the suction clamps (I have 10 good ones and 2 that are possibly good if cleaned up but possibly not) and I can toss the 3M primer + urethane (which may go bad by the time they're shipped over) in the box too, let me know. I sealed the window weld with a screw in the cap and then zip tied the finger from a rubber glove around it, so it's possible it stays good for a while - who knows. Clamps by themselves were almost $100, so I'd let it all go for $50 shipped.

These are the clamps: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Last edited by awns729; 10-28-2020 at 02:39 PM..
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      10-30-2020, 12:47 PM   #12
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Oh, and the most important thing I realized is if you use comfort access to bring the soft top down partially to relieve the tension, the car will bring it back up with force. If you turn the car into accessory mode (or start it) and use the interior buttons to relieve the tension, the top will stay unpressurized if you turn it off immediately (if I remember right). I was having a hard time lifting the rear section upwards to access the clips holding the top in until I realized there are certain scenarios where the car wants to close up the top and other scenarios where it'll let it hang. I was terrified of getting the clips back on in time but if you do the right combination of actions, you can have the car off and the top de-latched in an intermediate position with no time limit to work around. I opted to pull out the clips at the rear end of the top and flip the back fabric up above the window because my entire glass fell out. Others with less severe damage would be able to leave it in the unlocked / loose position and glue without removing the rear fabric clips. Hope this helps the next person!

Edit: Other notes... You can definitely scratch the glass with a razor blade. I didn't realize that it's pretty easy to do this when you're focused on just the glue area and was working in low light, so I have a lot of small scratches, especially in corners.

You can put small 6 x 6 x 6 in or so boxes in the corners to support the metal rails on either end of the top. This keeps the back glass / fabric 6-12 inches off the base of the car and is a good way to work for cleaning up glue or doing the final knock in of the fabric clips back into place. You'll also want to consider having something to push the glass up from the inside when reattaching the fabric. This guy's video will give you an idea of how to reattach (and therefore detach) the soft top fabric from the back:
)

When you inspect how much has become unglued, know that the top folds in on itself around the section that glues to the glass (OP's second to last picture). I didn't understand this until I got in there. Obviously you'll want to insert glue there too. Tension from the clamps should be enough to hold this seam shut as well. I glued the seam first and then glued the glass right after, and then clamped the top to the glass, which should apply pressure on both layers.

The working time (55 degrees, 75% humidity was my situation - see their PDF for details on how this affects curing time) of window weld is long enough that you should be ok, even doing this by yourself. Just preposition the suction clamps before you start gluing. A second person helps if you have a large section. 3 of my clamps fell off after I glued, so I was rushing to get them back on and doing the entire bottom half at the same time alone, so I didn't get absolute perfect alignment on the left and right bottom corners, but I'm still happy with it. Better luck with the clamps or having a second person or breaking it into 2 sections would have all helped.

Last edited by awns729; 10-30-2020 at 02:29 PM..
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      10-30-2020, 01:33 PM   #13
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Thanks for the great information!
We should clip this into the forum library
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      10-30-2020, 02:15 PM   #14
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Here are some photos of the process. I measured from edge to edge of the window and placed masking tape to mark the center line for help with alignment during gluing. Final photos are before cleaning off all the glue (despite the amazon reviews, cutting excess glue away seems to be possible even 2-3 days after it's dried). It looks pretty good in person. Slight kink on the bottom left because I didn't get the edge of the fabric high enough on the window.
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      10-30-2020, 02:24 PM   #15
awns729
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Quote:
Originally Posted by Mandinca View Post
I had to do this fix last year when the rear glass separated from the fabric along the bottom and up one side. I scraped away as much of the old adhesive as possible and took the tension off the fabric by propping the roof open with a basketball and some towels under the back (before it closed itself under gravity).
Then I used those clamps and glue mentioned above (3M Window Weld) which, I have to say, is amazing stuff. I also used those free paint stirring sticks to try to spread out the pressure from the clamps. I also used a tiny can of 3M primer that you put on first, don't know why but I read it somewhere in another thread about this.
This is my third attempt at fixing this and while other glues held for a couple of months, this stuff has held for over a year.
One issue I do have is that when I took the clamps off I noticed that there was a small kink in the fabric at the lower left corner of the window. Think of it as too much fabric kind of bunched up in a small ridge. Well, with opening and closing the roof that ridge has frayed.... :-( It's not terrible but I can see it and it will only get worse I suspect.
Back to the glue. Once it has cured fully you can cut it with a razor blade to tidy it up. I'm not entirely satisfied with the look but it worked :-) However, I still have the rattle if I close the roof, but only for the first mile or two then something settles into place and it goes away. Overall, happy with the results, just wish I noticed that kink sooner.
There's a place I found online that sells these roof covers for $1000 but I was unable to find a DIY and didn't want to tackle this myself.....I have enough issues....cam ledge for example. N54 life I guess.
In the OP's last pic, see that hole on the metal bracket near the window? There's a plastic piece attached to the very bottom / rear of the interior fabric lining that clips into that hole. One on both sides of the interior lining. Climb into your back seat and go to the bottom edges of the glass, and you should see what I mean. Is it possible that's causing your rattle?
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      05-10-2021, 10:28 AM   #16
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About 6 months in and I have a little separating at the bottom lip but it's still holding and water tight. Unsure if it'll hold here or if it'll continue to get worse. I may try regluing the few separating sections. Curious for other people's opinions on this.

Edit: March 2023, still holding strong. Those separating areas were probably poor adhesion, maybe because I ran a paper towel through to clean and it left fibers.
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Last edited by awns729; 03-20-2023 at 09:37 AM..
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      09-27-2023, 05:22 PM   #17
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Glad I found this, thanks to all who posted. Also helpful that the pics still work! But I wish now I hadn’t attempted it in an over tired state😢.

awns729: the painters tape is a great idea to keep that **** off the fabric, also a great idea to do the top first, let set up, then get the bottom.👍

I however made the false assumption that I could do it all in one go. Leftover ego from automotive background (from a past life) I guess. i Had difficulty after getting the bottom part secured, so I had to bail on the top part, which should’ve been the reverse if anything. I was still up at 3am putting in new vapor barriers in the doors, so I finished the top part of the back glass after that. Seriously tho I must be a bit of a sado, butyl tape or urethane, which is worse? I hate them both 🤠.

At any rate I now feel confident I could offer this as a service if I had a shop, but I wouldn’t lol. I found a few things made my life easier, or would have, had I done a dry run first(kinda like it says on the tube of urethane). Might be redundant but if it helps someone not have to deal with what I did then that’s great and it gives me some relief just thinking about never having to deal with this again.

1. Kind of goes without saying but make sure the glass and surfaces are clean. Blow it off with compressed air if you can, to get bits of lint or paper towel, dust. Wipe surfaces to be glued with 91% IPA. I used those blue shop towels to clean, then a ‘lint free’ terry folds cloth🤣, then blew it out with compressed air. If you don’t know what a Terry Fold is, look it up lol.

2. If nothing else this would’ve helped the most. Get your clamps and stir sticks set up on the glass so you know where you’ll need them to be exactly before hand. For the more anal person, numbering them might help. Trimming them a bit to fit better actually helps a lot too. Might not seem necessary but once you expel the glue is not the time to be runnin around trying to figure **** out, it does actually set up pretty fast. Once you get the clamps and stir sticks set up(after glueing), it helps if you move them sightly so there’s almost a little overhang from the edge of the convertible top. It will tighten the gap up. You’ll have to trim a little of the urethane that squishes out.


3. Don’t worry too much about excess urethane(unless it’s in the fabric at which point you’re kind of screwed anyway). It will easily come off with a razor blade once it’s set up, even a thick bead will come off clean if you (careful not to cut into the edge of fabric) cut both sides. It will also pretty much come off like plastidip on other smooth surfaces. I believe this is why a primer is needed in some cases(to etch the surface so it will actually stick).

4. Work clamps not only work great on the lower corners but help prop it up so you can reach around😅if you have to move the glass or push the top down like I did 🙄. I used rubber tire chocks to support the top section which probably kept me from smashing the glass with a hammer due to frustration. Oh ya, I would recommend NOT scraping off all the old glue on the glass, just enough so it’s fairly level and uniform. The urethane sticks a lot better to that than bare clean glass(ie: unprimed).

91% IPA seems to clean this stuff up just as well as Acetone but acetone eats some plastics. IPA can soften some plastics too but it takes longer exposure on most plastics and clear coats(according to reading). IPA is also way cheaper but wont get you high from huffing it🫠🤷*♂️💀😅.
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      09-27-2023, 05:24 PM   #18
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Interior is another project, swapping grey to coral. But. Holy **** when did I become such a long winded windbag….��������
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      09-27-2023, 05:39 PM   #19
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hah! glad you were able to DIY and save some money.

FWIW, mine's mostly holding. The bottom is partially undone but still holding enough to make a seal I think (will have to double check one day). That's probably my fault for wiping with regular paper towels before gluing. From other's reports, I may be able to scrape away and reglue that section one day. But 3 years and holding so far. I'll take it.
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