I have a garden hose faucet on the outside of my home in the front yard that is loose in the surrounding brick. It can be wiggled freely and has a good 1/4" clearance between the pipe and the brick that it goes through into the house. What can I use to seal it? Is there a specific type of caulk? Would I need to use a small amount of concrete?
I would personally use Loctite PL Polyurethane Concrete Crack & Masonry Sealant, which will adhere well but still provide a degree of flexibility as your pipe moves within the brick. It's grey, but you can also mix in a little concrete dust or dirt to give it that "I'm not shiny caulk, honest!" look.
The PL product should be available at your local home improvement stores. (Homer's or Lowe's or Ace or whomever.)