[Bill Scott]

That's what I did.
You'll need to use an X-acto knife to cut open the male/female mating sections.
edit, Here is my original piece

 

[Bill Scott]

I used a piece of 1/16" thick gasket material and made one.
Glenn

Hi Bill, Thanks for posting that pic, I was in the same situation wondering what took up the clearance in that join. Has the gasket got a 90 degree fold both sides or only one. Its difficult to tell from the photo. If you could take another pic slightly rotated that would be great. Also do you know how thick the gasket is. cheers Ian

It does a have fold on both sides, The materials looks and feels like gasket material, which is what I made my replacement from. I don't have a micrometer, but an old caliper showing it is 3/64 inch thick

.