Belts
About 20 years ago I bought “new” leathers for my 104 and 114 machines and the leather was old I guess. They kept breaking, and I hate the replacing the clips. I went to my air condition/ plumbing supply and bought regular fan belts from them. I have never a problem since.
I called all over town and found one long and thin enough to fit my 29-4 but I had to cut it to get it on the machine. That was not easy to clip together