If the top of a Z-Bend can break, then the bottom of a Z-bend can break! This would mean that a simple 90 degree bend can probably break as easily! This is not a good scenario!! We are talking about a "Work Hardening" of the material in the location of the bend. Some push rod wire, seems to be harder then it needs to be and the action of bending further hardens it. The less bending which is done, the better. This wire is also capable of being annealed (softened). You can tell the difference between harder and softer push rod material as the hard, is much more difficult to bend. The annealing process is a simple matter of heating the material and bringing the metal up to a "Straw" color (this is just previous to the metal turning blue) and dipping (quenching) the material in some type of oil. Given that there appears to be harder and softer pushrod material from different suppliers, find one that has softer material and stick with them. This makes me wonder if manufacturers are unaware of this potential problem! (This information comes form 25 years in the manufacturing trades and 22 years as a tool and die maker).

When quenching I suggest not breathing the fumes! Hi Piper!