Brad i didnt move the pump at all I picked up some t handed allen wrenches with a ball end(5mm) from sears and it allowed me to remove the upper rear bolt ,after i took a pick to get all the crud out of the hole, but you could mark the pump and housing like you said ...mine was marked from the factory with 2 lines (I have owned the truck since new and only i work on it exept a/c) make sure you have the allen wrench down in its hole so you dont strip it out.and the only thing i think might be scary is removing the spring from the top hat ...DONT DROP IT! I took mine out after pulling the spring end off it so i could work on the pump top end of the spring
Robert

 

DON'T DROP IT!! I think you put a hex on me!!! So that short spring is unhooked from both ends, the top hat and the other side from that arm and that is the only thing replaced?

Brad

 

Yes ... one end of the top hat sticks through a hole and the spring to it other is on a little arm in the top part of the pump once you unhook it the top is free to look at and dont worry about how the spring goes on just hook it back (nowrong way)up

NO hex... only an allen wrench
Robert