Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Thought I remove the pump and show some photos of it, it's a pretty simple design.

The pump is made of a upper, lower hollow shafts and a center.  The lower has a small check ball inside (the ball must move freely) and the upper has the pump shaft.  The upper shaft will not come out when you remove the slip nut/knob and there is a o-ring that goes into the cap of the slip nut to keep water from shooting out the top when you are pumping. I could tell someone tried to remove the lower shaft because there are deep plier marks on it.  I also tried to remove it and it would not budge - those shafts are really screwed in!

The center bit that the upper/lower screw into is also for screwing into the tank.  Inside between the middle and tank is a check ball and spring.  The spring must be strong enough to keep pressure on the check ball but not to strong it keep it from allowing water through.  

I have a Stainless Steel Spring set with 15 various sizes.  I used one that was 5mm wide and cut it to length.  Then I used my pliers to pinch over the end so the check ball would not pass through the spring and into the tank!