Replacing the FD RX7 Keyhole Flap

Over the past 30 years the little plastic flap that covers your door keyholes likely has disintegrated into nothing. This leaves the keyhole open to water and other nasties; it also just looks unappealing. Additionally, if your FD also has the keyhole illumination working, then the light isn’t properly diffused.

If you search around on the internet, you may find kits to replace the stock spring and flap, but at the time of writing this post, all of the vendors are out of stock.

So I decided to take matters into my own hands by fabricating my own flap. The only problem? I didn’t have one to reference, so I had no clue what the dimensions should be. Sure, I could take my door key cylinder out and start measuring, but I was way too lazy for that. Instead I spent a bunch of time trying to find if someone online had published the measurements. To my amazement, someone in-fact did publish the exact measurements I needed. Those measurements are replicated below:

Armed with this information, I quickly modeled something in Fusion 360 and sent it off to my Prusa MK3S to print. I chose a clear PETG both because I want the light to be diffused/seen and for PETG’s strength properties.

After taking my door handle and key cylinder out, I plopped it right in and it worked great.

For those looking to do the same, you can grab the file I modeled here.

Luckily I still had the spring in the cylinder, albeit not as strong as it once was. I haven’t been able to figure out where to source a new spring as of now. I will update this post when I do (if anyone reading this knows a good replacement, feel free to send me a message).