I am going through a Deming piston pump that hasn't been used for about 50 years. I've owned it all that time and never had a use for it. Now I have an unused Dankoff DC motor and PV to run it and want to try to get it pumping. I have found the leather cups at an Amish on-line store called Lehman's. The last thing I am concerned about is the packing nut side of the pump that is gasketed. I can't figure out how it is held together. It seems like when you remove the pump from the frame that piece should come loose, but after tapping it, it doesn't come apart. Either it's really stuck, or there is something I don't see holding it together. I can feel that there is a thick gasket (it might be leather too) in there behind the packing nut housing. My plan now is to put it together and see if it leaks.