89 (and prior) convertible sidewall speakers.


Active Member
Mar 13, 2019
Pittsburgh PA
For those with 90-up Foxes, you have it easy! Ford decided to revamp the sidewall designs and un-bury the back speakers from the lower rear sidewall and move them to the upper sidewall.

This write-up is for those with 1989 and prior Foxes, I don’t know how far back this speaker arrangement goes. This also for cars with “Premium Sound” or six speakers. I think the four speaker cars only have the dash mounted speakers and the ones in the door, I am not sure.

Some things to keep in mind as we go along:

- My 89 GT convertible is my first project car. I bought it last year from the original owner with only 69k. But it sat for ten years in a DC parking garage and the original owner didn’t exactly care for it, but he didn’t beat on it either. Lots of TLC needed here. I wasn’t going to do the back speakers, but I had everything off to fix the quarter window motors, so I figured why not? I’m keeping this car stock, but upgrading when I can.

-I am NOT a natural wrench, nor do I work on things for a living. My dad was an airline mechanic and my younger brother got most of his mechanical skills. But I like to DIY when I can and don’t mind “sweat equity” when it’s within my abilities, which this car is expanding on.

-This is not all inclusive, there’s YouTube for stuff I have probably missed. The idea for using the material I bought came from a YouTube presenter CarAudioFabrication. Gotta give credit where it’s due. I’m not sure this material or using it was the best solution, but it worked. I wish I had all the fancy tools he has to work with!

This is your nemesis, the rear sidewall speaker. Ford used a 6.5 or maybe a 5.25 speaker and riveted it into place. The mounting holes fit nothing aftermarket, so adapters are required.


I found some adapters from Metra for Ford/Mazda products that seemed like that they would work. And they did, barely and for about a second after a test fit. It was probably my fault trying to make it fit on the test fit (I wasn't even rough on them) but they broke: This is an unusual application they weren't really designed for, but they're really thin plastic too.


Back to square one and to Google. After searching and coming across a YouTube installer video, he used this: Cellular PVC trim. Basically, it’s plastic house siding and it comes in various styles, lengths,etc. Since I’m doing this during the pandemic and going to the store is an ordeal, I ordered what I thought I needed online from the orange big box store for pickup. Shopping in person you could probably fine-tune your purchase.

The piece/style I ordered was about $25 for 8 ft of material, perfect for multiple attempts if needed! The Metra adapters were $11 on Amazon for reference and they broke!


Following steps from the CarAudioFabrication video, I made a template by tracing the original speaker onto the material:


Rough Template.jpg

I made marks where the factory mounting holes were, since they are the biggest factor here. I marked them in blue to keep track because placement and orientation are a huge factor here:


I then placed the new 5.25” speaker on that material and traced it, marking the mounting spots. You will want to mount the speaker so that the connection is facing up so it clears the body of the car. Pilot holes are a great idea! I used a 5.25 speaker because it’s what was listed for fitting by Crutchfield. 6x8’s are listed, but I don’t think they’ll fit in pre-1990 cars. 6.5 would probably work too, but you’ll still need adapters.

To cut the material, I used a Rotozip tool that I inherited years ago and never used. It is an awesome tool, but I know not everyone has one. A jigsaw would be fine, just make sure whatever you use, the blade can cut PVC. The first blade I used didn’t cut PVC and basically burned it. That is not a smell you want to have around and probably not a good idea to breathe!


From left to right: Proof of concept to semi-finished product. I did LOTS of trimming with a Dremel to get the fit in the car just right. This material is just a bit too thick, if I did it again, I’d use something thinner. I’m not sure if you can plane it down and I didn’t have any way to evenly reduce it down, so I didn't try. The space in the car has some wiggle room because the factory speaker has about 1/4 gasket on it.

Putting it back in the car, I used some short screws that I had. #8 ¾ or 1” worked fine. The good thing with this PVC material is that screws bite and hold with no problem.



Again, the fit wasn’t perfect but it worked. Getting the rear side walls back on was a huge pain in the butt, be sure to make note of how it all goes together. It really took me some muscle and time to squeeze everything together and make it fit. But I don’t think it was due to the installation, because I tried the opposite side without a speaker while it was still apart and it was still a huge challenge. ( One of the mounting tabs broke off which is why there’s only three shiny screws and a black one).

This was definitely way more work than I wanted to get into with this project. I hope it works and I hope it lasts. And hopefully, it helps someone else do this task! I just hope I don’t have to pull the sidewalls off any time soon! I hated getting them back on more than anything. On a final note, I didn’t glue the carpet back to the panel, just in case I need to revisit this in the near future. Cheers!

CarAudioFabrication link: Don’t know the guy at all, but here’s where the idea came from:

View: https://www.youtube.com/watch?v=G9hZ1H9m7Ko&t=202s
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