Larry,
Page 17, last item with a Hillman part number is a push rod. Also, a clue you gave about the pin coming out, if it had come out far enough for Item 16 to drop out, the pump lever may not be aligned with the push rod as it is a spacer to centralise the lever. As for fitting an electric pump, well you can if you wish but nothing wrong with AC lift pumps if in good order, it is yours or the owners choice.
regards, Richard