Before taking the cover apart, the first thing you have to do is mark it. If you don't mark at least the corners, you'll more than likely sew the new cover together wrong. Things can get out of kilter while you're sewing if you're not careful, and those marks will help you keep things straight.
I marked the corners by just drawing a line across the seam with a Magic Marker. There are better ways of marking the old cover, I know, but this is what I had at the time. It's also recommended that you use a straight edge to draw your lines - which I didn't do. What happened was, I had turned the covers inside out, and cut "witness marks" in the seams - basically just cutting a notch in the edges of the layers of vinyl that make up the seam where ever there's a corner. Bob watched me do this for close to 20 minutes, then came over, and told me that it's easier to just mark it from the front with a pen or something. My reply was, "Well, sure - if you want to do it THAT wayâ€¦" I marked both covers with a penâ€¦
This seat back features a large back panel that wraps around to the sides, and the insert is sewn directly to that. The insert also runs over the top of the seat back, then is sewn to the back panel at the top rear of the frame. This back panel will be plain black vinyl.
With all of the corners marked, plus some additional marks here and there just to let Bob know that I took him seriously, I began cutting the seat covers apart.
Picture 1: The seat back cover removed from the frame and foam. The corners are marked, and it's ready to be taken apart. Notice the listing at the bottom of the cover. This is made from a fabric known as Cambric. It's the same stuff applied to the bottom of your sofa as a dust cover. This listing is basically a loop of fabric sewn to the bottom of the cover, with a stiff wire running through it. This is what you hog ring to the seat frame.
Picture 2: This picture shows the top seam of the seat back. The insert wraps over the top of the foam, and the plain panel makes up the back of the cover. Again, I'll be eliminating the welt.
Picture 3: I tucked a rolled up piece of posterboard into the cover so I could get a good picture of how this corner went together. I figure I can't take too many pictures of details like this - I'll need them for future reference. This is the bottom corner of the driver's side of the seat back cover.