I had the same problem with a broken wire on an Ampico air motor as
Bruce Mercer describes in the 090807 MMD.

I could not find a wire replacement wire anywhere.  I finally
fabricated one from a piece of wire coat hanger.  It was not threaded,
but inserted with friction.  Once I had it the right length, I set the
wire in with epoxy.

It has worked fine for the last sixteen years.

Bruce Clark