About a week or so ago, I noticed our water pump was cycling 'way too fast - IME this ALWAYS means the pressure tank has lost its air pad - it also means you either FIX it or start saving for a new PUMP :thumbdown: - About 12 years ago I'd replaced the pressure tank and re-plumbed everything with valves ANYWHERE I thought I might want one, and they've come in handy more than once since -
Anyway, I valved off the tank inlet, which leaves the pump/pressure switch isolated from the rest. This keeps the pump from cycling like a crazy guy in spandex :laughing: - then closed the valve to the house and drained the water ('nuther valve) out of the tank -
Checked the air pressure (exact same tubeless tire stem as car tires) - had SQUAT. Brief self-congratulations, interrupted by REALITY - after it took several minutes, I got the air pressure back up to 30 (pressure switch is on @ 40, off @ 60, air needs to be LESS or NOTHING works right) -
Heard a small hiss, spit in the valve stem, sure 'nuff - replaced the core - no hiss. turned water valves back on, pump comes up to pressure, HISS IS BACK

- turns out the SECOND leak was 'cause the rubber on the valve stem had separated from the brass threaded part - squeezing it made it (sorta) stop -
Couple wraps with electrical tape, small lawn-mower type spring hose clamp, no more hiss -
Til the next morning when it was doing its "spandex" thang again
Oh, and I woulda replaced the stem the FIRST time, but "ya can't GET there from here" - without un-plumbing the whole tank, emptying it, removing the (sealed up) water bladder so you can get to the INSIDE surface of the tank TOP to insert the NEW stem....
Google NOT being my enemy, I typed in "how to replace tubeless tire stem WITHOUT dismounting tire" - ignored all but a couple of the "64,337,291 results in .00057 seconds"
And ordered THIS
Amazon.com: AME 5125 Quick Valve Change Tool: Automotive
One reviewer said it sucked, wasn't worth a nickel, couldn't, yada yada - but everybody HERE knows "that guy" and won't even CONSIDER loaning him tools, he'll just BREAK 'em and SUE ya

- The rest were a bit more "real world" - yeah, kinda hard but doable, etc...
It's 'sposed to rain again here about Friday, so I wuz REALLY hoping for delivery SOONER - it showed up TODAY.
If you read the info on that link, you see the kit consists of an "Egyptian embalming hook" on steroids, a threaded tube you screw onto the new valve stem, a fairly comfortable handle for the OTHER end of that tube, a TAPERED tube and a couple valve stems - most comments (and the directions) recommended copious quantities of lube, such as vaseline, dish soap, etc - I opted for the dish soap, offered up a prayer to the pump god and went for it -
"That guy" wasn't entirely wrong; it's a good thing the embalming hook is sturdy, 'cause the old stem was fairly happy right where he wuz - then, even with those copious quantities of Dawn I wasn't sure who was gonna WIN - I weigh 190, and I was REAL CLOSE to putting all my weight on that "fairly comfortable handle" before the new stem finally gave up and popped in...
Aired the tank back up to 30, water valves back on, pump came up to pressure and shut off, TOTAL SILENCE from the "hissy fit department" - heat lamp's back on, all covers back on, my feet are thawed out (it's been 25-30 nights here, up to 40's days)
Think I'll call it a win.... Steve