I don't know how, but when I installed a new mastercylinder in my car I was bleeding it and it was fine. Then the next day when I went to do the final bit of bleeding on it, it felt notchy like it was binding or something. And then my pedal went to the floor. I looked at the clutch rod from the master cylinder and it was bent about 70 degrees. How the He!! did I do that?

yup, had that happen to mine too, still not sure how it happened.

A friend has done it before.

Anyone else figure out why this happened. I am at a loss

all I can think of is that if there is any binding of the piston in the bore, that pushrod should easily bend with leg pressure and the leverage of a clutch pedal; quite a bit of ratio advantage that the leg has. Never had that problem myself