I am wondering why, now that power steering pump on my truck has been changed, the pulley will no longer stay on. When my dad originally changed the pump he did not have the proper tool to press it back on, so he hammered it on. Ever since it was hammered it on the pulley will no longer stay on. We have tried another new pump but the pulley is the same. Anyone have any Ideas on how I can keep the pulley on. Will a locking nut or something keep it on?