One of my last posts on my topic in big bolts shows my seat bein finished up.
It had mostly good springs and the frame was good, but the pan on the bottom was trashed. Interestingly enough I recently cleaned out a uphosltry shop that was closing it's doors so I had al the new springs I needed, plus donors from another seat. Some of the structureal rods that the springs mount to were rusted through, you can bend fresh rod to fit or use parts from another seat. once it was all together I cleaned all the metal and added a liberal coating of rust converter then a coat of black rust-stop paint. I dont know if the older seats had pans, but for mine I found a local HVAC shop that cut me off some steel for the pan and was nice enough to bend it for me too. I trimmed it to fit the frame, assembled the springs and bolted on the rails.
The original padding consisted of a layer of burlap over the springs, hog-ringed in place,
I used denim I had on hand Then a layer of about 2" thick matting (looks like horse hair), I used 2" thick foam rubber myself, & should cover the whole top and roll over the front of the spring a bit. The next layer was 1/2" batting, not totaly needed, but helps fill the rolls if you get a tuck-n-roll cover. If you get a plain cover it's optional.
If you want to make a cover, some good textured black marine grade naugahyde works fine, but it's worth the $ to get it done or get a kit if you're not handy with a sewing machine. Getting the cover on square can take a couple tries, the spring clips that newer seats used made that easy (part number UP220 on Americanclassic.com), if yours uses hog rings you may want to get a few small spring clamps to get it sorted out before you perforate it. I had to take the edges off and adjust a few times, but overall for a quick custom job I think it's pretty good.
My finished product.