I installed a frost-proof spigot recently but nothing came out when I turned it on. This short instructable shows the internal workings of the spigot and how to fix the problem.
I thought the problem was that I had over-heated the valve when I soldered it to the water-supply pipes. However, the problem was that someone had over-tightened the valve.
There was nothing I could find about fixing the valve, and I didn't want to dis-assemble the one connected to the water mains, so I had to buy another one for dissection. The dissection is shown below. Note the rubber valve seat on the right side of the image.
Step 1: Removal of Valve Seat
When I shut off the water and took apart the valve, the valve seat didn't come out. So I tried to screw a dowel into it. That worked, but it didn't hold. Then, by chance, I tried a 1/4-20 tap, which worked perfectly. The string was secured by a washer. The string broke. So I used a bit of twine, which was much stronger. The valve seat came out with a few hard jerks. It was not damaged and identical to the one I got from the new valve. So, I re-used it.