Watts outdoor hose bib leaking

[Dutchman]

I recently replaced the obvious washers in this hose bib without stopping the leak! I finally took out this long internal shaft and found an o-ring at the inner end which disintegrated as I pulled it out. On the bib is embossed Watts 101E. I live 35 miles from the nearest hardware store and would like to know the name of the shaft and washer if possible. I could take the whole assembly into town but I have to shut off the main water valve to the house and the water between the meter and the house would leak out....about 600 feet of pipe. The bib shown is identical to the leaking one but much easier to photograph. Any advice would be appreciated.