We'd like to use the original hand pump faucet in our '59 Rainbow canned ham but it's not working right. No matter how much we pump it doesn't build enough pressure to draw the water from the 5 gallon tank. It will work fine for awhile if we manually prime it either by funneling water or blowing into the line, but as soon as we shut it off there's no more pressure again. Any ideas on how to repair the faucet? Thanks!