holding the pump upright in your left hand with lever ponting towards the right insert srewdriver underneath the lever and make sure it is holding the internal piece of the lever up or it's normal stationary position. find a way to brace it in position. (in the crook of your elbow or have your apprentice hold it whatever does the job)then pres metal center of diaphram down while pushing it slightly away from lever side it should pop loose and spring will push it out. the metal center of the diaphram assembly has a flat rod on the underside. This rod is slotted near the bottom, the interior end of the lever has a slight hook on it. By holding the lever with the screwdriver and then pushing down and slightly outward you allow the slotted end of the diaphram rod to drop below the hook in lever and slip off the end allowing easy removal. Sory I can't post pictures right now, this computer doesn't recognize my camera and the one that does keeps restarting, have to dig out old computer and hook it up.
I did finally realize both valves in my pump are likely the same just reversed for in flow and exit. still haven't figured out how to remove them.
