I have one of those long, freeze-proof hose bibs (outdoor faucet). It
has a small round plastic thing on top of it behind the valve stem. I
assume it is an extra safety precaution in case of water freezing in
the hose. Recently, water has begun to poor out of that plastic area
whenever the faucet is opened. Is this something that can be repaired
or does the entire hose bib need replaced?