I have four hoses at my house and they all failed over the winter and started flooding the house. I'm going to fix them one at a time.
I've unscrewed the first one and pulled out this:
I expected this piece to have a hole in it, but it seems solid. I don't have the slightest clue by what principle it opens and closes the flow of water.
I then cut a hole in the ceiling and found this:
The brick is about 2 feet away so I'm not really able to reach it. I would appreciate any advice on the steps I should take to fix this problem.
Edit: to answer the questions asked in the comments:
The hose was not attached. I live in Philadelphia and I believe it got below freezing, There is no insulation in that crawl space. There is no rupture in the stem. I'm not even sure where the water was coming from but I'll investigate by carefully turning the water on.
UPDATE: Video of the leak.
UPDATE 2: Managed to disconnect the pex and pull out the assembly. The following is a picture of the rupture. To me, it looks like they used type M copper, doesn't it? I thought that M was against code.