FMC SX60 BREAK AWAY BOLT?

[Snowroute]

Does anyone know what bolt you'd use to attach the PTO driveshaft to the SX60 spline? As I recall, one of the more important characteristics of the bolt was that it not be too hard, as they snapped easily and a softer grade was recommended. I can't seem to find that info in my owner's manual or online.

Thanks for any help.