I'm resealing a Crosman 140 and I reassembled it yesterday and the pump won't go but maybe 1/2 way to the stock. Also, I can't find the center piece that is in this photo between the #140-56 "Exhaust Valve Ring." This is the first Crosman I've attempted a reseal and I've found I'm at a loss, maybe my 140 never had the part of it rolled off the desk onto the floor somewhere. (The center dark part). Sorry this is confusing, you shou,d be sitting where I am! But that part eludes me.