I've had a 1959 311B & a 1956 310 for about the last 20 years, they both have that rod. The 310 spent most of its known life doing loader work on a dairy farm, notably scooping manure in the barn an adjacent areas. They both have done a lot of loader work since I have had them also putting a home site in a heavily wood 6 acres so the clutches got a workout. I have had to replace worn down clutch friction disc on both, also replaced pressure plate & release bearing while they were split so they clutch operating linkage has been worked. No signs of the rod fracture you have.
I have the linkage well adjusted as per that diagram I posted. I suggest you do the same if you haven't already done so. Breakage like that would appear to be from a twist as the clutch pedal is pushed down, something to eyeball.