How to Reattach Rear Window Glass to a Convertible Car Top

Co-authored by wikiHow Staff

Last Updated: September 14, 2020 Approved

Modern soft convertible car tops often have glass windows glued to the cloth, vinyl or other soft material with a melted plastic strip instead of a clear vinyl window sewn to it. If and when the glass comes unstuck -- sometimes due to the canvas shrinking from neglect or otherwise -- it can be very difficult to reattach. Double-sided foam tape such as 3M VHB tape (what one author used, others could be OK too) can reattach them, but should be applied in a specific way to avoid constant strain that will break its bond.

Steps

1
Reattach the soft top material ("canvas") to the glass when just part of the canvas has detached so that the glass does not have to be re-centered within the hole in the canvas. If it does have to be re-centered one might do that by measuring distances with the defrosting grid as a guide and, in any case, holding the glass temporarily in place with gaffer's or other sticky tape.
2
Open the top slightly so that it is not taut. Prop something such as a small empty box between the front edge of the top and the upper edge of the windshield frame so that the top stays open slightly.

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3
Find the seal that was attached but has become unattached, such as the lower edge of the exterior layer of canvas.^{[1]
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Research source} If dirt has accumulated in the pocket that has been exposed to the weather you may wish to vacuum out any large particles.
4
If only a very small part has separated leave it alone. If a large part is mostly separated you may wish to separate it entirely to re-seal it as one continuous piece.^{[2]
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5
Clean the mating surfaces with rubbing alcohol.
6
Close the roof completely to see where the canvas falls on the glass when pulled gently flat as far in on the glass as it will go, but not pulled hard. At least in the case of cotton canvas, this will probably be not as far up onto the glass as originally (or as on a still-attached inside layer) because it will have shrunk since new.
7
Re-open the roof slightly and re-prop it.
8
Apply a strip of double-sided foam tape such as 3M VHB ("very high bond")--foam so that it will conform to any irregularities, preferably black so ultraviolet rays will not promptly destroy its exposed edge--to the glass with the edge coming up to the point you determined previously.^{[3]
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9
Bring the middle of the area being attached (such as the middle, left-versus-right-wise of the bottom exterior canvas) up to the edge of the tape. It should have just a little slack, since it needs to be pulled basically smooth but not taut when the top is closed. Just a little slack when the top is closed is much better than tension, which will unstick the tape.
10
Stick the canvas to the tape, working outward. The reason to work outward from a central point is so that any "excess" material does not build up at one side.^{[4]
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11
Rub down the canvas over the tape firmly and apply some heat--not a great painfully hot amount--with a blow dryer for a thorough bond.
- The convertible top should be fixed.

Community Q&A

Question

How much will it cost to replace the top with the original window?

Community Answer

I have a 2007 Mustang convertible. The window is separating from the cloth top. I went to two convertible top/upholstery shops, and both told me the window is heat sealed and the entire top needed to be replaced, and both gave me a price of $1,900.
Question

I have in my garage a Corvette convertible with a canvas top in great condition. The seal around the glass rear window has popped, will this procedure work?

Community Answer

I used 3M window weld on our 2004 Volvo C70 top and it worked great! Make sure you get as much of the old adhesive off as possible. Put the 3M primer on first and let it dry for about 10 minutes. Put a bead (about 3/16) of window weld on it. Clamp it in place. I used some paint stirrer sticks & C clamps. Let it sit for about 24 hours. Do not do this if temperature is below 40 degrees F.
Question

Where can I get 3M VHB foam tape?

Community Answer

Amazon has it in a variety of lengths and widths.