How to Fix a Silcock Spigot

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.