Peter, when I tried to bend mine forward it kinda sprung the whole cotter pin. When I was browsing through the drawer of cotter pins at the hardware store they had them in brass, aluminum, stainless, and steel. I think this one is steel, since it looked like the right size but this size was only available that way.
If you bend the loop downward, and the legs open up, you can hold the loop from the side w/ a pliers and then bend that upward leg back down again.
My cotter pin was aluminium, so it bent easier. If I was doing it again I'd use stainless, even if it is harder to bend. If yours is steel that's gonna rust.