Convertible Window Replacement

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“Real sports car enthusiasts,” the first new Mini Cooper convertible advertisements seemed to imply, “have their tops down regardless of how much it is raining or how cold it is outside.”

Indeed, this seemed to be the attitude of the vintage British sports car owners on the Scions of Lucas email list I had subscribed to a dozen years ago, back in college. It is a philosophy I had adopted not only for my MGB but for the BMW Z3 and Alfa Romeo Spider I had subsequently as well. It helps that here in Fort Collins has 300 days of sunshine and hardly receives any rain, especially in winter.

So this explains why for the first 50 days in 2006, the Alfa’s top remained perpetually in the “down” position. That is, until the first major CO snowstorm of 2006. It was 0 degrees Fahrenheit in the garage, and I conceded it was time to put the top up.

As I begrudgingly did so, I heard a sickening snapping sound. I looked behind me and was not amused. Crap! The rear plastic window had completely split along its width two inches from the top of it!

Apparently, it was so cold in the garage that the normally pliable PVC plastic became so hard and brittle that the mere act of flexing it when putting the top up caused it to break. (Supposedly, this happens more frequently with older tops since the plasticizers leach out of the PVC over time.)

I then threw up my hands, resigned to the fact that “shit happens,” and threw some clear packing tape on the split. “Good enough,” I thought, at least until the same scenario repeated itself ten months later (a few days ago) when I once again attempted to put the top up on a rather cold-but-starry night.

It was time to finally replace that rear window.

Unfortunately, unlike on my former Z3, the rear window was sewn in instead of held in by a zipper. This meant I needed to replace the whole top or have a new rear window sewn in.

Exploring the former option, I learned that a brand new cloth top like the one already on the Alfa is $650, a vinyl one $350, and a used 1971 top about $200 on eBay, not including shipping.

I then called a local upholstery shop, Jerry’s Upholstery in Fort Collins, about sewing in a new rear window if I were to remove the top from the car myself and bring it in. “It’ll be about $85,” said Todd, the convertible top specialist on the other side of the phone. He even remarked that he might be able to sew one in on the same day I brought in the top. Perfect.

All I needed to do, then, was remove the whole top from the car and separate the fabric from the top frame and header rail. (Todd would not have been able to get the fabric within the sewing machine if I did not do this, he told me.) This turned out to be pretty straightforward, though time-intensive (about 3 hours).

See the photos below that outline the procedure. Essentially, it entailed undoing a couple dozen nuts securing the top’s canvas to the car body, unscrewing a few bolts attaching the top’s frame to the car, and separating the fabric that was glued and riveted to the frame and header rail.

Then I brought in the fabric to the shop, where Todd snipped out the old plastic, cut a new window to size, and sewed in the new plastic to the inside of the convertible top. He did complete this on the same day and did a beautiful job. (I highly recommend Jerry’s Upholstery to anyone in the Fort Collins area now.)

Installation was the reverse of removal. This required the use of a rivet gun, something I once had but apparently lost between the move from Fremont, CA to Fort Collins last year. (No worries; I was able to obtain another one from Harbor Freight for just $6!)

Some lessons to be learned from this ordeal:

  • If you have a convertible top with a plastic rear window, exercise some caution when raising and lowering the top in frigid conditions, especially if your top is old. Temperatures below ~30 degrees Fahrenheit should raise a yellow flag.
  • In questionable conditions where you must raise or lower the top, consider busting out a hair dryer to warm the plastic and make it more pliable.
  • Tops are best stored in the “up” position.
  • If the rear plastic window needs replacement (and is the non-zipper type), consider getting a new one sewn it. It is much less expensive than getting a new top and less labor-intensive for the do-it-yourselfer since rivet holes in the fabric are already punched, etc.
  • If possible, consider having the plastic replaced with glass. I didn’t seem to have this option for the Alfa, but I know Miata owners can find aftermarket rear glass windows rather easily for even their first-generation cars (which where the only Miatas that came with plastic rear windows).


On a couple of days when the temperatures were too frigid, the rear plastic window became brittle and split when I raised or lowered the top. :(


An "after" shot.  So much better than when the rear window was cracked/taped!
Removing the top from the car required removing a couple dozen nuts on studs, then undoing a few bolts securing the frame to the car.Then I needed to separate the fabric...... from the frame and header rail.  Since the fabric was glued/riveted on, it took a couple of hours.Felix Wong riveting in the convertible top -- now with replaced rear window sewn in by Jerry's Upholstery shop in Fort Collins -- back to the header rail.

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Your Voice

  • Alyssa says:

    That sounds like it was a much-needed project… It’s cool that you’re so mechanically inclined and can do that yourself!

  • Lee says:

    I need to replace the rear window on my just-purchased ’87 Alfa Graduate and was searching the internet for relevant info – thank you for providing your excellent instructions!!! One question, what did you use to separate the glued sections on the top to get it off the frame? Just work at it with a scraper or simply pull it apart?

  • Felix says:

    Hi Lee, thanks for dropping by my site and for your comment. I merely separated the glued sections by pulling apart the fabric from the frame using my fingers and, in a few cases, pliers. A hair dryer (to warm up the glue) may help soften the glue, but I didn’t find that necessary. Good luck!

  • Joe says:

    The same thing happened to my 1990 Mazda Miata. I lived with a cracked and cloudy window for several years before I decided on a diy project. I decided to just glue a new window in with the top in place. It turned out pretty good, but not professional. You can check it out here.

    Thanks for your tutorial!

  • Carolyn says:

    A neighbor of mine has a 1998 Chrysler Sebring convertible. We got the rear plastic window but it did not come with any instructions as to how to put it in. Most of the auto shops in the area want $300 just to sew this in. Do you have an alternate method that we would be able to use to sew it in. It seems that all is needed is to get a huge needle, and some heavy thread and follow the seams around it and sew it in. Any suggestions?

  • Derick says:

    I lowered my Boxters top and left it in the garage (Los Angles) and the temp got to about 50. When I raised it it had some waves buckles and crinkles. Can I use a blow dryer to undo some of the damage I caused.
    Thanks Derick

  • Felix says:

    Hi Derick. In my experience, after putting the top up, any buckles, crinkles, and creases will smoothen out quite a bit on its own within a couple days. I hope this is the case with yours! Even indentations seem to “heal” naturally quite a bit. It may be a function of what plastic was used, though. Good luck and happy motoring.

  • Ron says:

    I have a ’74 Alfa which a mechanic left outside for over a year without my knowledge! The rear window is fried from the Tampa Bay sun and I was prepared to spend $750 to replace it. After reading your post I am hot on the path of replacing the window and NOT the whole top.


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