Just got a new ignition key cylinder and it will not seat all the way. I even exchanged for another one thinking that there might have been a defect in the casting. The old one, that was old and not working correctly, goes in and out freely when in the "run" position, after depressing the pin. With the new cylinder in the exact same position, it only goes in one way because of the groves and the retaining pin, it will slide about 9/10ths of the way and stop, just enough that it will not lock into place. I have changed several over the years and this one stumps me.