Some Silca pumps can stop working because the rubber seal on the end of the rod (think a small plunger) can dry out and shrink/shrivel if the pump was taken apart for some reason. Then no amount of grease can make it "grow" back to the correct proportion to fill the metal barrel and be able to pump. This happened to my nice Silca pump a few years back, and I've been using a cheap Nashbar model since then.
My question: does anyone know whether you can buy these sorts of parts (the rubber "plunger" head) from Silca?