Well, that is a poor quality part. It's unfortunate because back in the day they were much better. B&K, Mueller and a few others decided to go the cheap route to appeal to the demands of box stores pushing for low prices. The castings are terrible and the low grade materials have created a lot of problems.
When I get a service call for those I no longer repair them, I tear them out and replace the whole unit.
Arrowhead, Legend or Woodford are decent brand names......but even those are getting worse. I wish I had better news for you but even the top names in the industry are getting bad.
I've been putting in Legend T-550's lately and customers like them. Arrowhead has a hose bibb with an internal vacuum breaker that looks nice but I've been hearing about those failing again from some of the plumbers I know who use them.
Not really the best advice but that's mainly because I'm sick of fixing all these brands.
On my house I installed Legend T-550's. You can order them online.