Replacing main water supply valve

All,

After 15 years of using the house main water supply valve to turn off
water to the house it no longer completely shuts off the water. My
sense is that the seal inside is not fully functional and the outside
water pressure is enough to maintain a flow even though the valve is
off.

So, could anyone suggest the best plan from here. It looks like the
valve is soldered in. It's located just outside the house.

Do I have the city shut off the house water, hacksaw out the old valve
and solder in a new one? There is one nut between the body of the
valve, around the shaft. Is there any chance I could simply open that
up and pull out the guts of the valve and replace just that?

Quite frequently simply cranking down on the nut below the knob will tighten
things up so the valve works again. You can only play this magic once or
twice; so if it works, install a new full bore ball valve after the old
valve. I did that while my old valve was still working, cause they don't
last.

(tighten means clockwise when looking down on it; I don't want to think
about what will happen if you screw it off)

Thanks for any advice.

There is a good chance you can repair the valve seat or seal, it may only
need a rubber washer (if you have not mashed the valve seat trying to turn
it off with a bad washer). Can't say for sure not knowing what valve you do
have.

You will still need to shut off the water at the curb. You can do this
yourself if you have the tool or the city will probably do it for you for
free as long as that is all you ask for.

If it comes to replacement, use a 1/4 turn ball valve since it will always
be all the way open or closed and are most reliable for this application. A
gate valve would work too but is not as reliable.

Adding or replacing the pressure regulator at this time would be only
marginally more work and money if the old one seems worn out (visable
cracked rubber seals like on mine or cannot adjust because shaft is stuck
etc.)

Call the city. They will fix their own valve. I suspect you are
talking about a valve near the water meter. Precede from there.

Oren
"My doctor says I have a malformed public-duty gland
and a natural deficiency in moral fiber, and that I am therefore
excused from saving Universes."