Replacing a vacuum break

[Gamma]

I have what I assume is a broken vacuum break on the hose bib outside of my garage. When I connect and pressurize my hose, I get a big spray through the black ring used to drain the pipe down. I've never seen this type of pipe draining device before either, so its doubly difficult.

It's about 3-4" from my exterior wall, so it's quite tough to get at. Any recommendations of how to get this off? Is it possible to drill out the set screw and just remove it with a pair of pliers? Also, any recommendations on a new device to install once I get this off?

Here is a picture of the hose bib: http://imgur.com/YFZG2Q5

 

[Matt30]

The vacuum breaker should just thread off

 

[johnjh2o]

If you look at the front center were it is screwed onto the hose bib you will what is a broken set screw. That set screw was designed to break off when tightened so the vacuum breaker couldn't be removed. The only way to remove it is to drill the set screw out.

 

[Matt30]

I did not know that. Thanks John!