One of the greatest downsides of owning a convertible is that, if your car has a soft top, there are so many nightmarish ways for it to go wrong. A vandal can slice your top, the top mechanism can get jammed in the open position, the top can shrink, or maybe the plastic window gives way, allowing the outside in. My new-to-me 1998 MGF had that last problem, and its vintage plastic window broke apart, letting water in. Here’s how I fixed it with only hand tools, some time, and a shocking lack of swearing.
This month, I brought home the 1998 MGF that I bought back in June. I had wanted an MGF ever since I discovered them many years ago, but sadly, the stars just never aligned. That finally changed this year when I found an MGF in really solid condition for sale in Japan for around $2,000 plus shipping, fees, and import costs. This car had been the cheapest MGF I had seen in a while that ran and drove without major cosmetic or suspension issues. Most of the other MGFs that I’ve seen for sale in Japan sold for twice or more.
That may lead you to ask about why my car was so cheap. I wondered that, too. As I flipped through the photos on Be Forward (an online marketplace of Japanese cars for export), nothing seemed obvious. But then I saw the issue buried deep. At some point, the rear plastic window had cracked and broken. Who knows how long this car sat out in a yard with rain allowed to get in? I even found signs of mold, though I’ve fixed that before. But the photos looked good and the inspection sheets didn’t call out any red flags, so I rolled the dice.
Everything Wrong With My MGF
As I recently wrote, I am pleasantly surprised that the car is in such good shape. My MGF has absolutely zero mechanical problems, no rust, good paint, and a mostly great interior. Seriously, I found only two problems inside of the car. One problem is that the HVAC vents are a bit floppy at the bottom. The other issue is that the door card fabric came off.
So far as I can tell, the fabric falling off the door is a common MGF problem, and you can either glue the fabric back on or replace it with a custom cut of leather. The fix is super easy! The seller of my MGF even gave me the door card fabric, too, so I don’t even have to source the part.
The only other problem I ran into is the convertible window. Someone at the yard in Japan was kind enough to use darn near a whole roll of packing tape to seal up the window. Amazingly, this patch job kept out most water. It even held during the road trip back home. But it was a ticking time bomb. I had no idea when the tape job was going to stop working. Normally, I take my time fixing a car, but I didn’t want to chance this window coming apart during a strong fall thunderstorm and ruining the interior.
But even if I did ignore the cracked window, the window was also so oxidized to the point where seeing through the window was impossible. Having the opaque rear window made me feel like I was driving around in a bunker, not a lightweight roadster. So, I had to fix it.
Thankfully, I planned ahead.
Window Replacement Options
Before I bought the car in June, I researched what fixing the window was going to look like. I found plenty of online threads and a few videos. All of them suggested that replacing the window was an easy task for the average home wrencher. Keep in mind that the oldest MGF is from 1995, so by now, in 2025, so many of these plastic windows have broken that fixing them is not a big deal.
Based on my research, MGF owners tend to take one of two routes when their back windows inevitably crack and split. If they want to restore their cars to original condition, they remove the remnants of the plastic window and ship it off to someone in the United Kingdom on Facebook who can install new plastic for under 100 pounds. If these people don’t want to deal with the headache of the back window ever again, they can get a glass window upgrade.
Most of my cars are garage queens, so I didn’t really care about doing the full glass upgrade. Besides, since I live in the United States, shipping a big automotive-grade window in from Europe wouldn’t be cheap.
Living in the United States put me in a bit of a pickle. I would have to remove the bad window, ship it to the UK, wait for it to be fixed, and then pay to have it shipped back to the United States. Of course, my car wouldn’t have a rear window for that whole time. I also couldn’t be sure about how the current U.S. government would handle me exporting and importing what’s nominally a car part.
Thankfully, there are parts suppliers online who sell entire new plastic convertible roof sections. Sure, they’re much more expensive than sending the window to someone online, but there were several advantages to just buying a whole new part. I was able to order the part ahead of time, and it was sitting next to my apartment door for a whole month before the car even landed in Baltimore. I also didn’t have to deal with exporting a piece and having it shipped back.
I purchased a new rear window section from Cabrio Supply, a company based in the Netherlands. The part I received was made by BAS International and included all of the parts that I needed to fit it. The tools I used on this project included a basic power drill and a hand riveter tool. That’s it. Seriously!
If you’re an MGF owner and you stumbled upon this piece, I will warn you that if you’re ordering an entirely new window, you need to pay attention to the zipper type. According to MGF Mania Ltd, a respected supplier of MGF parts, the MGF used three different types of zippers. Early MGFs built in 1995 and 1996 usually had 7mm YKK zippers, while some cars had 7mm Opti zippers. Cars built from 1997 to 2006 should have an 8mm Opti zipper. These zipper types are identifiable by looking at the zipper slider. The type of the zip should be embossed or engraved in the slider.
This is important because if you try to interface a YKK zip with a newer Opti zip or vice versa, it’s not going to work, and you’ll be more or less screwed.
I confirmed that I had purchased a new window with an 8mm Opti zip, but I had no idea if that’s what my car had. If a previous owner of my vehicle had worked on the roof before and replaced the zip with an aftermarket version, there’s no telling if the zip was going to work. Thankfully, BAS International does ship its new windows with both zip halves in case you do run into a situation like this, but installing a new header zip is a lot more work than just replacing the window itself.
Because of this, when I got to work on replacing the window, my first task was seeing if the zipper worked.
Installing The New Window
This was easy. First, I unzipped the broken plastic window. Once the zipper got to the end of its run, I took the key to my apartment, shoved it into the metal stop at the end of the zipper, and then twisted. This popped the stop out, allowing the zipper to run its full length, which allowed me to detach the window from the zipper. Then, I positioned the new zipper and gave it a try. It was a perfect fit!
Perfect, now that I knew that the window was going to zip in, I moved it out of the way and got to work removing the old window.
To start that process, you first want to release the back of the convertible top. To do this, open the car and look at the “package shelf” in the rear. You’ll see a set of briefcase-like latches. Release all of these and then push up on the rear convertible top frame to raise the rear of the top.
Now is a great time to check under the carpet to see how rusty the metal is underneath. I’ve noticed that several British MGFs are quite rusty in this area. Mine isn’t that bad!
Once you have the rear of the top raised, you’ll find roughly 10 or so rivets holding the window in. These are made out of really soft metal, and a 3.5mm drill bit will make easy work of them. Be sure to get the entire rivet out because you will need to use these holes again in a moment. One thing I will note is that there are two rivets hidden behind the sides of the convertible top fabric that you will also need to remove.
This YouTube video is a huge help:
Once you finish zapping out the rivets, the remnants of the old window and the fabric surrounding it will easily pull right out of the car.
Now, it’s time to install the new window. If you bought your window from BAS, the baggie of fasteners should include more rivets than you actually need to complete the task. Installation is technically the reverse of removal, but how hard it’s going to be will greatly depend on your riveter. The guys who have made YouTube videos on this subject say that the whole project will take you around 40 minutes. But these guys had fancy air riveters. It took me three hours. Why? It’s because I bought a cheap hand riveter from Amazon.
This riveter did exactly as it said on the tin and installed each rivet with ease, but the tool is supposed to automatically eject the excess mandrel, and that part never worked. It took me a very long time to figure out that I could clear the jam by repeatedly squeezing the handle while forcing in a new rivet, which eventually forces out the mandrel from the rivet I last installed.
I suppose this could have also been a skill issue. This was my first time using a riveter of any kind, so maybe my technique sucked, too. Using a hand riveter is easy. You install a head that matches the size of the rivet that you’re going to install. Then, shove the mandrel into the riveter. Shove the rivet through the material that you want to secure, and then squeeze the handle a few times until the riveter makes a loud pop. Rinse and repeat for all rivets. In practice, the steps, at least with my cheap Amazon riveter, involve clearing a jammed mandrel.
Anyway, installation was easy once I cleared the jam. The convertible window from BAS came with the holes pre-drilled. So I just needed to align each hole to the convertible top frame and an associated rivet, punch in a rivet, and repeat a bunch of times. The hardest part is making sure the window doesn’t drift out of alignment while you’re setting up the next rivet. A second person can make this easier, but it’s also pretty easy to do yourself.
My one piece of advice is to test-fit the window first, making sure that each rivet hole actually lines up. If you mess up the alignment, you might not notice until you get to the last couple of rivets, and then you’ll have to start over.
Otherwise, the project is simpler than it sounds. Once you button up all of the rivets, zip back up the window, close the roof, and admire your work. I will note that, most likely, the foam seal between your roof and the body of the car is probably roached, so you’ll want to replace that. But for now, it’s a job well done.
Well Worth The Work
It was a night and day difference for my car. Not only can I now see what’s behind me, but the interior now feels much more light and airy, and all I did was change out a window.
I’ve noticed that MGF owners generally have two methods for opening and closing the roof when the window is in good shape. Many people just unzip the window. However, fooling around with the zipper takes a couple of minutes, so some people buy a pool noodle and put it in the window when they fold the top down. This prevents the window from creasing when it’s open. For now, I’m opening the zipper.
This project didn’t cost me that much money. The convertible window was $319.95, including shipping and import duties, while the riveter was $24.81. Aside from the annoying jams, which other reviewers on Amazon have also reported, the riveter did work. Anyway, as I said before, it’s possible to have this done for even cheaper. A boat canvas shop might be able to fix this, and, depending on where you live, you might be able to send the original window off to someone on Facebook who will replace the plastic. In my case, I just wanted the easiest way to fix it, and this worked!
After I reattach the door trim and pump up the suspension, I’ll be done working on this car. I can’t believe I’m saying that. I’m so used to having cars that always have at least one problem, but this MGF is apparently so nice that I don’t have that problem. Well, that is for now, at least. Either way, this just makes me so much more excited to spend the last of the warm days left in Illinois having some drop-top fun.
The key to getting a riveter that actually releases the mandrels is to buy the ones shaped like a bolt cutter rather than the ones that look like a big channel wrench.
I’ve tried three channel wrench type riveters and all three jammed, even after much fussing with the nosepieces, inner jaws, jam nuts and nosepiece carrier. (I don’t know the actual part names other than the inner jaws.) These ranged from $25 to $55, as the whole time, I thought the results I was getting might be from me trying to cheap out. So I kept buying more expensive units trying to end the problem.
After borrowing a friend’s and finding how much better it worked, I bought a $9 bolt cutter shaped riveter and it’s worked perfectly every time.
Eventually I’ll buy an pneumatic or cordless electric rivet gun, but for now, the bolt-cutter style rules.
Love convertibles, although I don’t own one at the moment (slowly trying to convince the wife). Owned three, a early 80’s LeBaron, a late 80’s Mustang, and a 9-3, all bought used at around five years old. The LeBaron’s top literally split apart at every seam within two years (charity donation), the Mustang never had a problem till I gave it to my daughter who promptly trashed the whole car, and the 9-3 had no problem with the fabric or window, but developed pneumatic problems raising and lowering the top at about five years so much the top seldom came down.
I really admire the effort Mercedes puts into her projects, I could not for the life of me do these things.
I have slightly higher quality version of that riveter and it works quite well. Mandrels can get caught in any riveter, but usually don’t jam in such a way that the next rivet doesn’t push the last mandrel out. Inexpensive battery powered riveters also work surprisingly well. I sometimes use stainless steel rivets and they take a LOT of muscle to pop, which is why I bought a powered one.
I could clear the jam by repeatedly squeezing the handle while forcing in a new rivet, which eventually forces out the mandrel from the rivet I last installed.
As others have said, basically welcome to pop-rivets. I have an ancient one made by the “United Shoe Machinery Corporation”, and a cheap Harbor Freight one, same results..
That little car looks lovely and was such a good deal. Every time I read an article about it, I’m just so happy for you.
You might’ve “saved” some money by having a shop replace the plastic, but in the long run, doing this way is well worth a few extra bucks. Time and labor are worth money, too.
That glass window from England, though…that’s actually not a bad price for what you’d get. If you were planning on hanging on to the vehicle for a long while, I’d think it’d be worth it.
That little car kicks ass and will confuse more than a few drivers… “What the hell is that?!”
Mercedes, that is a good looking car. Congrats and now that you can use a rivet gun, buy an old snowmobile for this winter!
Love it when a project comes together (relatively) pain free!
I recently replaced the entire convertible top canvas on my e30 because the back window was in a similar condition as yours after releasing tension on the top so i could pull the interior apart to deep clean. a pity, since the top canvas looked to be in great condition until i folded it too far and the clean, good condition looking canvas split between the top frame stretchers in multiple spots
I bought a deep green canvas top from from ebay, all the recommended tools and lubricants and adhesives, and studied every diy i could find, including one from ECS tuning
it took about a week of working on it for two hours or so every night, and locking the top in place to stretch it tight for a week before dropping the top for the first time, but it certainly makes a dramatic difference
There are some spots where the tension isnt right and there’s some ripples in the top, but i’ve never replaced a top before, and this one has sealed against all of the torrential rain we’ve gotten in raleigh the last two months so i’m quite content with it
If you have a plastic window that’s just cloudy, there is a plastic spray polish called Plexus that does a fantastic job of restoring old plastic. It works on convertible windows, helmet visors, goggles, and even CDs.
As an owner of an NA Miata who’s had this happen, I am quite salty that yours was this easy to swap out. My only solution was replacing the entire top.
For anyone looking for a non-jamming (also potentially non-Bezos) rivet gun, the Stanley riveter that they sell at many hardware stores for like $15 has been reliable for the last nearly decade and has never jammed. We also used Arrow ones at work, which look to be around the same price as that Amazon one was, and I’ve not jammed one of those either.
Kudos to Mercedes! Plastic windows are the bane of convertibles! My first car was a 1974 MGB and one of our first projects was replacing the top. My dad did it, but it was always hard to do up all the snaps. After that, I had tops installed professionally. He did almost all the repairs on that car, including a clutch replacement, but we never did another top. (I did have a Snug Top hard top for it.) One year I just did without a top (I’m in Southern California and I could borrow a car on rainy days.). I think one top did have a zipper but I remember it being a hassle to unzip and I did not want to jam or break the zipper. Drove that car ten years.
Then I had a 1988 BMW 325i convertible for the next seventeen years. I went through a few tops, maybe three? I remember one spring after a rainy El Niño year, the first time I dropped the top, the canvas tore across every seam where there was a bow. It was like something out of a cartoon. I got good at driving with poor rear visibility because I was too cheap to replace the top when the window inevitably grew opaque. I forgot but after I had the car for many years, I might have found a shop that would just replace the window without replacing the top.
Now I have a 1989 Mercedes 560 SL as a weekend car. I have the hard and soft tops. The top is definitely not new but it hasn’t suffered too much from being folded. It has three pieces, so maybe it’s easier on the top? Car has only 45k miles so it could be the original top. For a while I have had the canvas top up as it’s a big job to remove or replace the hard top. The soft top needs adjusting with the passenger door window. I don’t fiddle with the top much. It’s down for a long time or up for a long time. It’s definitely a fair weather & fancy neighborhood kind of car. It also stays garaged, which helps.
My son has a 2006 SAAB 9-3 convertible with the power top and glass window. It’s so easy, and the area in the trunk where the top folds… that area has a flexible cover, so you don’t lose the trunk space when the top is up. I bet it’s the original top as it leaks a little over the door window.
I am envious of your little MG. I saw one a couple of years ago at a local car show. Definitely find a British only car meet up. Go visit David when the Queen’s English car show is in Van Nuys, California.
My husband and I both had convertibles for our first and second cars, so it was really important for our son to also have a convertible. It’s like a chick imprinting on its mama bird. We both love SAAB, and seeing those crash test videos made it a relatively safe choice for a convertible. It even has little pop up back seat rollbars just in case. That car also has the coldest blowing AC of any car we’ve ever had (including other GM products.)
In my experience, no cheap hand riveter releases the mandrel like it’s claimed and I always have to clear it before using the next rivet.
I don’t use riveters often enough to spend money on them, so I don’t know if quality / known brands release the mandrel like you’d expect.
That is a very satisfying result for the effort and cost involved.
Our ’77 MGB has a fixed vinyl rear window and I’ve noticed that the rear corner windows will crinkle if left folded down for more than a few hours. So we put the top down when we’re out-and-about with it, but I put it back up as soon as we get it home and back into the garage.
I was at the British Car Field Day in Sussex, WI (Milwaukee area) this summer and the newest MG there was from the ’80s. A 1995 MG would really turn some heads there.
https://britishcarfieldday.org/2023-bcfd-pictures/
(while the link shows 2023, the photos are from 2025 with some 2024 photos below)
I’m a known SWG partisan when it comes to autopian accounts of repair daring-do, but looks like he’s got competition!
My Porsche is old enough to have a vinyl rear window, and I’m achingly slow about putting the top down to protect it. I do it in stages to ensure no creasing, nice gentle rolling, etc. I look ridiculous getting in and out of the car with it pointing dorkily straight up, but it’s worth it – it’s still original.
Nice work. What a difference!
Cheers to a very satisfying repair, the car looks great!