Convertible Top Window Repair DIY

So I had been trying to find an inexpensive solution to repairing my convertible top rear plastic window. It was delaminating at the bottom corners, and it quickly got worse. I was quoted repair prices of $750 - $800, and top replacement (from GAHH) installed locally for $1500. I didn't want to waste $800 on an old top, plus I need to save $ for upcoming brakes, plugs, and clutch jobs. After much research, I went with a DIY repair. This thread will document my experiences. I ended up with doing a multi-step sewing and gluing process. The results aren't perfect visually, but it's better than it was, and it doesn�t leak. I consider this a temporary repair until I get a new top in a few years. I think this will last until then. Besides, I am mostly top-down or hard top, so I can live with it. I'll post a full DIY write up below. Warning, the writeup is long. Before & After Photos:

Below is a link to my "Convertible Top DIY" repair write-up. Warning: it's a 10 page PDF. Window Repair DIY.pdf The repair is only a week old at this point. If you find this thread in the future and want an update on its longevity, PM me and I'll post an update. Enjoy

frisbee91, Nice writeup

Fris, you are the man! I'm in the same situation and can't imagine parting with the $700 to fix this window. I'm going to give your method a try

Did you consider just coating the back of the threads with a little silicon? That should prevent the stitches from leakiing.

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I thought about that, but that would allow water to penetrate the canvas, and get into the space between the canvas and the window assembly. I was worried that it would get nasty in there. I'll see how the Porsche waterproofing spray holds up. The "Plastiseal" product is also an option. Another thought... If your top is Navy Blue, I have about 4000 extra yards of thread . The color match isn't perfect, though. You could also try to find a darker navy thread for a better match. It's really hard to get a good color match when ordering on the internet. Black thread could work on a Navy Blue top as well. Let me know if you have any questions, and be sure to post your results. Good Luck. Note: there WAS a typo in my PDF. The stitch length I used was 3/16".

I thought that was a wide stitch! Thanks for the offer on thread but I am black.

does anyone know of a way to tint out the plastic window?

Fris, if I use Gorilla glue can I execute steps 3 & 4 at the same time and clamp once?

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Well, you COULD, I suppose. Honestly, getting the clamping arrangement right was tricky enough with one seam. If I were doing it again, I'd take the extra day and do one seam at a time. Do the seam underneath first, then you can figure out how much the gorilla glue foams. Any excess mess underneath is hidden. Good practice for the second, more visible seam.

Great write-up. I tried the Gorilla Glue between the canvas and the plastic window and it didn't hold. I'm going to try again with the E-6800.

Some of my spots held better than others and they were directly related to clampability. Re-glued and re clamped properly and things look good for now

It is ALL about the clamping. If you use the E-6000 (or E-6800) make sure you have your clamp arrangement worked out so you can get it in place in a few minutes. Practice once (or twice) putting your clamps on quickly before you apply any glue. Have a partner handy. Let us know how it works!

Frisbee91, Thank you for your very complete description of what it takes to do this dyi. I have the 2000 version of your car, exact same color. I think I will invest a day or two driving it around town gathering estimates for a repair shop to do it. If they are too high it will motivate me to do things exactly the way you did. Thank you again. Any suggestions after a couple of years use? Apterr

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It's been about 8 months so far since I completed this, and the repair is holding up great. No leaks. In hindsight, the only thing I regret is using too much clear silicone at the end of the repair. Just a tiny bit between the edge of the fabric and the window would have been sufficient to seal the thread holes, but I used too much, and it doesn't look great. You can see it in the pictures. I barely notice the stitching, and I think that it adds a lot to the strength of the seam. (even though it was a pain in the a** to do.) I've polished the old plastic window with Meguiars PlastX a few times. It works OK to clear up the window, but it doesn't last. It's the kind of thing you need to re-apply. I'll probably end up re-polishing the window each time I apply wax to the car. Anyone have better luck reviving an old plastic window more permanently? What did you use?

I went with glue only and it is starting to lose its hold in a few spots. I can certainly re-glue but as you said in your original post this is a temp fix till it's time for a new top. I started with about three stitches and it was looking terrible so I stopped and stayed with glue only. I don't regret it if it means I have to re-glue as it still effectively puts off the new top indefinately.

I'm about to undergo this DIY. My window is pretty much in the same exact shape as yours was fris. The bottom completely separated. Any last minute advice? Any thoughts on another glue that you might have used jn hindsight? Still psyched with the job? Hoping that I can get it all done over the long weekend. I'll probably start the process by clearing the old glue this week, & re glueing the canvas flap thursday... and hopefully I'll be sewing by monday...

My previous post (#15) still applies. I used a combination of gorilla glue, E-6000, and 100% silicone. Others have suggested something called "automotive goop" that is supposed to stay flexible when it dries (unlike gorilla glue, which dries stiff), but I don't know much about it. If I were to do it again, I'd use the gorilla glue (black), UV-6800 (a uv resistant version of E-6000), and a VERY SMALL bead of 100% silicone (ultra-clear). See my DIY above for details. Oh, and finish up with a few coats of "Porsche Convertible Top Conditioner" spray to make the sewn seam waterproof. It's been about a year and my repair is holding up well. Good luck, and be sure to report back on your results (take pictures!)

Awesome, thanks. I'll report back with the results...

Well just finished... Here's the short feedback while I have a second. 1. Removing old glue. Found that a hair dryer & thin flexible metal drywall knife (maybe 1" wide) did the trick, & the goof off was good for the final wipe down. Like fris I didn't remove all the glue, but just about all the big stuff. Found the goof off to be pretty useless in the beginning.

Yes that's an ice scraper holding the back window up...

Then I sewed the back edges together, well I had some help.

Next I cut a piece of wood to match the curve of the window to clamp with. Gorrila glued the 1st seam... clamped and left for 48 hrs.

Then I used the same setup with the vinyl to canvas seam. The e-6000 glue is def more difficult to work with, spreads weird, gets stringy (think spider webs, so watch out for stray glue, & be deliberate). But after leaving it for 72 hrs, was amazed at the results. I definitely used more glue then the gorilla cause I've seen what gorilla can do when it foams/expands. Basically ran a bead of the e-6000 along the whole seam & then brushed it out, top & bottom... Only a couple spots did it spooge, but it's barely noticeable. Put the top up & it was like new. But decided to sew it cause wtf, I've gotten these far, right?

So about 5 hours later, 3 broken needles, and a couple blisters, a couple punctured fingers, here's the result. the thread is black (as is the top) it's just the reflection making it look white. One thing with the Speedy stitcher that I need to point out, DONT USE THE BOBBIN. Just feed the thread through the holes & let it hang out the other end. It makes it easy to replace a needle if you break one. With the thread all wound up on the bobbin, you're effed. I only did about 6" up the sides, it was getting late & I was tired. Plan on doing the whole thing, but man the top of the window is gonna be a bitch. Haven't done any water proofing yet, but plan on it & will report back with a final pic when I do. Thanks fris for all the help... honestly wouldn't have been possible with out your pdf...

Window repair only runs $400, fyi.

Not really adding much to the conversation are we? Tell me where? Also, got a place near Vermont that could get it done for $400? I spoke to 4 different places & all of then said they'd need to take the top off & at that point I might as well just get a new top. If there are people who've gotten it repaired, please share your experiences. If it can be done for $400, I'd like to see the results.

3 out of 5 shops I went to in the SF Bay Area would not even do the repair. Not one of them would do it with the top on. The lowest quote I got was $650 since the top had to come off and a new window installed. I did a repair like the ones shown here but less than a year later the original window is cracking above the bottom edge so it's toast now.

Respect. Looks great.

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Glad you had success. Looks good! I broke a few needles too, but got better at it as I went along. I bought some heavy-duty sewing machine needles that worked better than the needles that came with the speedy stitcher. I also did not use the bobbin, but forgot to mention that detail. I sewed the entire bottom and sides of the window, but did not do the top seam. I agree that it will be difficult, and mine is not delaminating in that area, so I skipped it. No issues so far. As far a final waterproofing, several coats of the Porsche convertible top waterproofing spray is great on the threads and the whole top. Mask off the plastic window first, and the paint. As I said before, if you go with a bead of silicone between the plastic and canvas, use it sparingly. However, if you skip that step altogther, I wonder if it would leak at all? Let me know what you end up doing.

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I had a similar experince when looking for someone to fix the window. I called at least 10 places, and most would not even attempt the repair, and those that did wanted $800 to $1000 to fix it. The guy that quoted me $800 assured me that Porsche did not make a convertible version of the 911 from the factory, so I must have an aftermarket conversion. I decided he did not have the Porsche expertise to work on my car For me, having the window fixed for $400 would have been nice. Since I couldn't find that, I opted for the DIY repair. Maybe I'll get a new top in a few years. Where? Do you have contact information? When did you get that quote? How was the quality of the work?

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It was a local guy on this site "programator" or something like that. He posted a pic a couple years ago. All I recall is that I had an option to pay $400 or $1400 but since my top was faded I went for the $1400 GAHH replacement. Good luck.

I ended up ordering Raggtopp cleaner & waterproofer. I'll report back on the effectiveness of that stuff. The needles I used were quite a bit smaller then the ones that came with the stitcher. I got a couple form a local leather shop. a smaller & then a larger (both smaller then the speedy stitcher ones tho) and on my 2nd stitch broke the smaller one, then only broke 2 of the larger ones... mostly form me not paying attention. In hindsight I could probably do the whole thing now without breaking one... but man does it take a toll on your hands.. blisters, cuts scrapes... Maybe I have girly hands. Haven't decided on the caulk or not.. sure does make it look messy if you over do it... We'll see... I'm rarely out when it rains anyways, mostly for "just in case" scenarios...

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You probably get what you pay for. Then again, all said & done I prob paid $100 for this... we'll see how it holds up. Initially I'm pretty happy.

Holding up fantastically. Looks great. Pretty psyched.

Attempting with super glue and a wooden furniture clamp, in small sections. Back later with results.

Major kudos to all who have tackled this DIY repair. When I was researching on getting a cab years ago, I learned about the issues with plastic windows for 99-01 996s. Helped me decide to limit my selection to 02-up only.

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I'd be curious to see how well the superglue works for this repair. If it looks like it's not going to hold up in the long term, consider the sewing methods documented above. My repair is 2 years old, and the stitching is holding up very well. The silicone bead is peeling a bit, so I plan to remove it. I will not replace the silicone bead, and I do not recommend using it at all. Best of luck with the repair.

The stitching looks and sounds like it is a major PIA to do. Makes me wonder if there is another mechanical fastening method that would work and look reasonably well finished. I note that the plastic window was not originally stitched to the top. I will consider hand stitching the window, before I consider spending the cash to have the top removed and repaired.

From my original questions it looks like my job is two years old. I did all the gluing with no stitching. It is just now separating on the one original corner where the problem started. I might can start over again but the original plan was just hold off till I got a new top. i understand they are just $1200-$1400. Don't drive in the rain anyway so holding off to see how things are going. Two years ago I tried a few stitches but just didn't have the skill to keep going so have no regrets. Might re-glue if easy and all in all am thrilled with Fris' original write-up.

After gluing and clamping along the bottom edge, I let it dry and then applied another bead of glue (super glue is thin and actually runs so this worked good on the bottom edge) along the bottom edge and let dry for 24 hours, in the full down position. I put the top back up and latched it to the windshield and it looks good and holds the tension well. Way better then putting the car on the shelf and dropping $1500 for a new soft top. With the right clamp, this is not a bad job at all and I encourage DIYs to take a crack at it. Only caution is go easy with the glue........ with too little, you can go back and re-glue that section, too much and you might have a real mess on the window.

Update March 2013. There's been a few posts lately about the 996 plastic window. I thought I'd give an update on my original post from 2010. It's now been 2.5 years since I did this sewing repair on my convertible top window. The repair is holding up just fine. My only outstanding issue is the silicone caulk I used on the window-to-canvas seam. I don't think it adds much to the repair, but it doesn't look very good. This spring, I'm going to see if I can figure out how to remove it. If you do the repair, avoid the silicone. Any suggestions on removing silicone caulk from canvas and vinyl?

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Frisbee I haven't had the car long enough to say it will last but the Novus 1,2,3 system worked really well to clear up the window and take out allot of the light scratches.

I would be looking to the world of scuba diving repairs if I needed glue for my rear window http://www.diverightinscuba.com/cata...ue-p-3182.html

Update: August 2016. This repair is now almost 6 years old. Still going strong. No leaks, tears, etc. The plastic window is starting to look pretty worn and scratched, so I'll probably do a plastic polish with PlastX or a similar plastic polish. But, no plans for an expensive convertible top replacement at this point.

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Hiya Frisbee..... I have the same issue with my '01. I tried the link to your original PDF, but the link didn't work. Would you still happen to have your original PDF? I put a new top on my Boxster myself, with no previous experience with anything remotely similar, and it turned out great..... But I have no desire to repeat the experience.... lol.

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Hmm. Not sure what happened to the PDF link. I will try to attach it here. (see below) FWIW, almost 7 years later, the repair is still holding strong. No leaks, no issues.

my corners have came a little lose, I wish i had the patience to do this myself because otherwise mine is perfect... I might need to grow a set and do it lol maybe I could just glue the corners back that would probably work, will that glue hold without the stitching?

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The E-6000 (or 6800) will probably hold if you clamp it well. But, if the corners are going, the rest of the seam will probably give out soon, especially in the heat of the summer.

yeah you are probably right

Thank you, fris! PDF opened up fine. Looking at mine tonight, my window seems to have shrunken maybe.... It is VERY hard to get the edges to meet to the point where the seam previously joined, even with the top in service position. I'm wondering how tough it would be to loosen the top from the bottom of the frame to gain some slack. Dunno how tough that would be. ​​​​ ​​​​

I just joined Rennlist, and this thread is why. It's fantastic to see the followups all these years later. Thank you! I may reconsider putting in a bid on a 996 cab I've been following.

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Haha. This repair is going on it's 8th year. Still holding strong, even though the window is getting pretty worn. I still polish it a bit every spring. The repair was time consuming, but it has sure held up. Another 3 years, and it will have lasted longer than the original factory seam! Took this photo today...

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It almost makes you wonder why they didn't reinforce the seams with a similar adhesive from the factory...

Hey folks, I guess I have a question on what is the best kind of polish for the top? I usually have the hard top on with glass window so I don't worry about it. However I'm planning on removing the hard top for long periods soon and my window is quite cloudy, what is the best way to polish it and clear it up? Thanks!

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There are several commercially available polishes for plastic windows. I've found the multi-step versions (like Novus) to be better than the single step like PlastX. Meguiar's Meguiar's makes a multi step polish as well, although I'm not sure if its better or worse than the Novus. I think I used the Meguiars.

OMG. I wish I found this sooner. I have a 1990 964 Cab, but the rear window looks like crap with many holes in it, but rest of the top looks fine, see pictures. I was told that replacing just the plastic was NOT an option, so I purchased a COMPLETE top with all the bits and pieces, including motors, etc. from someone doing a conversion from Cab to Targa. But I just discovered that you can "simply" replace the plastic per https://www.carparts.com/convertible...indow?&vehicle [year]=1990&vehicle[make]=Porsche&vehicle[model]=911&vehicle[submodel]=Carrera_2&vehicle[cylinders]=6&vehicle[liter]=3%2E6. Am I missing something? The only questions I have then are: is it possible to remove old plastic and replace with new without removing top should I work with an upholstery shop? how difficult might it be to get my motor working again to pull top up/down? A shop tried to adjust this a decade ago and couldn't figure it out, so I just told him to simply un-attach and I do it manually. assuming this works, who wants to buy a complete top with ALL the bits and pieces.

Frisbee91, Thanks much for providing the scaffolding and validation so that those of us who follow with the inevitable rear vinyl window delamination may have a better view! While I spent 3 months pondering canopy repair-or-replace options (as the corners started to delaminate), the entire bottom seam has delaminated. This happened very quickly as has been reported by others. Initially the seam will start to peel back from the window and the vinyl will slacken with visible creases when the canopy is closed... You have <6 months for action. Once a corner opens, you likely have 1-14 days before the whole bottom seam will fail (for me, it was a week, and that was without driving with the canopy up to avoid the pressure). I am electing the 'Frisbee repair' route (with minor mods). Here's the decision tree and planned mods (with justification) from my research/procrastination: Is the canopy in excellent shape, vinyl window delaminating?: \ YES \ is the vinyl window in good condition? \ YES : then proceed with stitching repair \ NO : Then replace entire canopy with a professional upholstery shop. Justification : The bulk of the repair cost is in the 10-hour labor to remove/reinstall a 996 cabriolet canopy in order to replace the window. Consensus among those who've done it is that they wish they'd installed a complete new canopy for ~$400 more than the cost of the replacement window. Labor cost is roughly the same. With few exceptions (mostly those who never returned/sold the car) those who made it a DIY install typically say "never again!" I'm resolved to stitch in situ with the following mods/additional thoughts: I'm a sailor. A well made bimini or dodger (with vinyl windows) will see more sun and greater water than my Porsche will experience in SOCAL. Granted, it won't travel at 126MPH with a grinning captain at the helm, however, it will also see significant wind pressure and often without the streamline profile of hte rear window of a Porsche. Marine vinyl windows are double row stitched with basting tape to waterproof the seams. Therefore I will adopt this approach. Vinyl is a bit like a postage stamp. It will tear very neatly along the perforations ...which is likely why Porsche didn't sew the seams... a glue that has bonded for 22 years of outdoor use on a sports car has probably exceeded the engineering specs for obsolescence - so I take my hat off to them (course that may change after 10 hours of hand-stitching). To overcome this perforation/tearing risk, use a #4 needle (smaller perforation in the vinyl) with V-90 thread, and a long stitch length (I plan on 10mm stitch length). The #4 needle doesn't come standard with the speedy stitcher, it has to be ordered separately. Many of the 996 repairs I've seen (professional and DIY) have altered the alignment of the canopy/put creases in the vinyl window (yours looks awesome BTW). To avoid this, it is paramount that the window is firmly held in place with the correct tension at the place where you are stitching. When hand stitching sails, this is done with an anchoring line that you pull the seam against while stitching. Not really possible when sewing a 996 canopy in situ. I plan to use two KREG 6" Wood Project Clamps at either end of a new stitch section to hold the vinyl/basting tape/canopy sandwich in tis correct alignment. A lot of attention will be put on correct tension at the canopy corners. I have considered using a glue to set up the initial bond and then reinforcing with stitches, but my thesis is that the stitches provide the holding and the basting tape provides the waterproof bond. Hopefully the result will avoid the risks of glue messing up the finish. I'm waiting for the clamps to arrive to start the project. I will post the results and help blaze the trail or erect the 'do not enter' signs for others facing this problem. Bottom line (as you have established) 10 hours of hand stitching with $40 in materials (less the clamps) versus 10 hours of removing/reinstalling a canopy with the associated risks of canopy function or aesthetic issues - its a no brainer. If it doesn't solve the problem, buy a new canopy and get it professionally installed. It is ultimately a consumable on a rag-top - we're all just trying to buy time without upsetting the form and function of a beautiful car!

For what it's worth, my repair lasted 12 years with no issues. But, this past spring, my vinyl window developed a crack. During those 12 years, the top had also faded quite a bit. So, rather than invest time in sewing a new vinyl window in an old, faded canvas top, I decided to replace the whole thing. I went with the smaller glass window version from GAHH and all new canvas. For my money, 12 years wasn't a bad run.

Awesome insights - thanks! Do you recall if the crack emanated from around the stitching, or was it a fold crease exacerbated by UV? If my 'Frisbee repair' works without looking too DIY, then I will start a regimen of UV protection on that vinyl window at each wash... I'll be happy if I get 3 more years life. I am considering the GAHH canopy for the final solution. I will likely stick with the vinyl window as I like to have maximum rear view when reversing to apologize to that air-cooled Porsche driver I just overtook

It was a cold-weather related crack at the fold. I shouldn't have tried to move the top on a cold morning.

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how do you like the glass window? It looks quite a bit smaller. M

The glass window is definitely smaller, but still functional. I think it looks much better, and won't go cloudy on me over time, so it's worth the minor distraction of a smaller rear field of view. But, when the top is down, the field of view is excellent!

Pretty happy with the 'Frisbee Fix' thus far (first row of stitches completed to re-bind the delaminated window)! 5-6 hours work for a serviceable canopy that looks pretty good and up to 12 years of extended life. Better investment than an IMS bearing fix! I have not put the canopy under full tension yet as I want to get the 2nd row of stitches in place to halve the strain on each stitch and prevent elongation of the penetrations through the vinyl. This window hasn't been fully stretched for over a year (when the delamination started and the window began to sag). The window also hasn't been cleaned of residue from my 'handiwork' or polished yet. The white strips in the photo are leftover pieces of the Seamstick basting tape adhesive cover that had not yet been fully peeled off. The basting tape seems a good choice at this early point in the repair. The real test will be after the second row of stitching is laid, the canopy is fully deployed, and I verify the watertight seams. A couple of 'manly sailmaker' tips that really helped. Obviously trying to dodge any potential seamstress labels here. I have photos if desired (of the tips, not my machismo): Make sure you re-attach the bottom edge of the headliner to the back shell before you start stitching - the rubber strip will probably have popped off the metal lip when the window delaminated. Its fairly easy to re-seat, just line it up and press down firmly, running your finger along the strip and you will feel it drop home as you go. It is not easily removed once on, so make sure you line it up properly laterally. I'm not sure that this can be done without many expletives (if at all) once you've stitched up the window. Use 1/4" Seamstick basting tape under the seams where the window has only partially delaminated and use 1/2" (or 3/4") where it is completely delaminated Load the 'Speedy Stitcher' bobbin with V92 (color-matched to your canopy) and use the #4 needle (sold separately). For the Metropol Blue canopy, I used V-92 Navy UV Bonded Polyester Thread (part # 100073 at Sailrite.com) - I went through 4 different shades of blue before I got a good match. When you load the bobbin (I used a drill), make sure the thread peels off the top of the spool to avoid winding up the thread - if the thread has any rotation it will cause the free thread to form knots as you stitch which will slow you down (best case) or form a knot that weakens the thread and causes filaments to break, at which point, you will have to cut it and backstitch over that area to form a strong bond as you start sttching again from the break. As you load the bobbin, run the thread over sailmakers wax. I may be just superstitions here with the V92 thread, but it does seem to help prevent abrasion of the thread as you stitch, which also makes the thread (and the needle) run more smoothly through the canopy. If you have access to a leather sharpening wheel on a tool sharpener (I have a Tormak wet grinding wheel), use this to hone the factory point on the #4 needle before you start stitching. If the needle starts to get difficult to push through the canopy, hone it again. I did it twice and it made a big difference to the speed and effort required. Run with 7 mm stitches... 4 mm back from the seam edge nearest the vinyl Mark this out carefully with a soapstone pencil in batches (I went with 70 mm batches on the straights and slowed down to 7-14 mm batches on the corners). This might sound tedious, but its actually pretty quick and makes a huge difference to the finish. Clamp about 100mm ahead of your active stitching section initially... once you hit the straight, you can open this up On the bottom line of stitching, tie a figure eight knot in the end of the tail, this will make it much easier and faster to pass through the loop made by the Speedy Stitcher, and it will also prevent the thread from unravelling. If you F@#$ up a stitch, don't just box on and hope that it will hold - it won't! And that stitch will haunt your best race track dreams. Just undo the work and re-do it. Frisbee got 12 extra years out of his canopy � what's another hour's cussing on that return. This job is definitely worth doing properly! And that brings me to my final point. I completed the closure of the window in four sessions totaling 5 hours - I really don't know why I waited a year 'researching' the best solution. I wish I'd done this before the complete delamination happened. It would have been far simpler and far more accurately followed the line of the original window seam. Will follow up with the completed job once done, and the window is at full strain/tested for waterproof, and polished to Frisbee standard. Sailrite.com provided most of my materials (other than #4 needles and soapstone pencil that I found on Amazon). They also have some excellent instructional videos on the Speedy Stitcher and on putting vinyl windows in dodgers and Biminis (albeit with a sewing machine in a sailmakers loft) that will help understand the basics After: First row of stitches are completed (window 100% sealed) and canopy at ~80% strain Before: Vinyl window completely delaminated along the base and both bottom corners, partial delamination half way up both sides. Window good (needs a polish); Canopy excellent.