I have a model 17 Woodford, frost free, that is leaking slowly when I turn it off. I was going to try to replace a washer at the end of the stem, but when I took off the handle and took out the packing material, the stem pulled out all by itself-no washers, valves . . . I can't get to the inside of the faucet because it is about 10" inside a wall with no access. Any ideas? Thanks.