Its easy to make new ones once the leaf spring pack is apart. Measure the ones left and cut the new flat stock the same length. Use a heavy rivet to hold the new strap on ( I found some at my local ACE hardware store ), then assemble the pack and bend the ends over. I use a piece of sheet metal, (.062" thick) as a spacer so the straps don't lay right on the top spring. I think the last ones I made were from 3/4" x 1/8" flat steel stock from the local hardware store.
I did have to use some heat to get nice sharp bends, but all in all its real easy to do.

Joe