The "D" shaped shaft hole in the original black lever was 5/32" diameter. Over time the hole had been worn round. I drilled through the lever and shaft and fitted a dowel pin. That worked for awhile, but any dowel pin (or spring pin or cotter pin) had to be fairly thin to fit through the 5/32" shaft, and it periodically sheared.
A new lever was fabricated out of aluminum that is longer than the old lever.
Because "D" shaped drill bits are difficult to find, and because I didn't have a "D" shaped broach, I created the "D" shaped hole as follows: