What you need:
*1 1/2 yards of heavy fabric, like duck or canvas.
*3 yards-ish edge binding. You can use bias tape, twill tape, foldover elastic, or whatever. I used foldover elastic because it's what I had laying around.
*Strapping and buckles (you can reuse the old ones from the stroller) OR plastic snaps.
*A screwdriver
*Patience and a seam ripper.
*About six inches of 3/8 inch elastic.
*Good polyester thread, like Gutermann or Mettler. Don't cheap out on this one.
1. Unscrew all the little screws and brackets. Set them aside for later.
2. Rip out all the seams and strapping, making careful note of where they are. Mark them with a marker if you need to. My stroller was so old that the creases were faded and ground in, and I didn't need to mark the seams.
3. Use the old fabric piece as a template for the new one. I would advise that you cut it a little too big, so you don't have to do it twice (like I may or may not have done...)
4. (optional. If you're not adding pockets, skip to the next step) cut out pockets. They can be any size that is smaller than the back of the stroller piece. I made two- one huge one and one pleated sippy (or travel mug) sized one. The pleated one I cut about 12" x 8."
5. (also optional. If you're not making new straps, skip to step ten), cut out straps in the same general shape as the one you removed. I would have used the old straps, but I couldn't wash the smell out. Plus, I seem to have trouble with pinching chubby little baby thighs in the buckles, so I went the snap route instead. Cut two of the center piece and four of the straps.
6. Sew the straps together, right sides together, leaving a hole for turning. Trim seam allowance, turn, and topstitch.
8. Add a snap stud to the top corners of the foldover as shown. Add the snap sockets on the bottom so that the top forms a flap that snaps down over the double row of snaps you added earlier.
9. Put snaps on the side straps as shown. I used sockets except for the crossover snaps, since the ones for the belly strap are studs.
10. Sew edging all the way around the edge of the large stroller piece.
11. Find your markings on the old stroller where the straps were and pin the new straps on to the new stroller piece in the same place. Sew the straps on the same way they were on the old stroller. Make sure you backstitch when you do this. Remember- these straps are all that's between a squirmy toddler and a display of crystal barware in a department store! They need to be on there tightly!
14. Mark all the little screw holes from the old stroller on to the new one. Poke holes with the awl through the new stroller in the marked spots, and insert the screws with brackets. Screw the new stroller on to the frame just like the old one.
15. Ta da! You're done! Throw away the nasty old stroller parts and take a walk with your spiffy new stroller!