1972 Duster Build with my Daughter

WTF: I got the NOS foot pump. The center piece I took out is SUPPOSE to be free from the rubber and come out..... How does this damn thing seal and work? Can anyone explain to me how this system works....
I dunno for sure. I have same setup on my '69 GTS and it is pretty "Mickey Mouse". Lots and lots of pumping for a very weak spray. Not good. I think if you really plan on using those washers much I'd get the conversion to an electric pump!