The rethresher was a weak spot on the masseys.  In my part of the world windrowing wheat and picking it up off the ground was common.  Never failed to get a small rock in the rethresher and tear everything up plus dirt just wearing it out.  It was common to see patches welded onto them.  The old man joked JD must have hired a Massey engineer when we saw the active tailings return upon introduction of the S series.  One of the reasons we stuck with S670s and not the 680s.