Fluidmaster Toilet Fill Valve

The Kohler fill valve in the Main Bathroom’s Kohler toilet tank began leaking, but (unsurprisingly) the shutoff valve on its water pipe no longer completely shut off, thus converting a simple replacement into A Plumbing Project. Because toilet shutoff valves sit below all other valves / faucets / plumbing, the pipe can spew a generous amount of water straight up while you’re fumbling with the new valve, no matter how well you (think you) drained the pipes.

So I deployed scrap towels around the pipe, buttered the new valve threads with joint compound, applied various wrenches with appropriate muttering, and swapped the valves without damage to the premises:

AFAICT, the chromed pipe and corroded trim plate are original; no possible motivation can convince me to replace that plate. The tattered PTFE tape on the pipe suggests the valve I replaced might have been only a few decades old, albeit with a correspondingly deteriorated washer.

With the water shut off, I replaced the fill valve with a Fluidmaster valve from Box o’ Plumbing Stuff #3; it was new-in-box despite being maybe a decade old. Turned the water back on, fiddled with the float setting to match the Water Line level, and declared victory.

Which lasted until user feedback indicated the new fill valve wasn’t shutting off. After a fruitless day of fiddling about, I replaced the original seal with a repair part taken from Box #3:

The fill valve now works perfectly, for reasons having nothing do with the the appearance of either seal, and victory has once again been declared.

Houses, as Gee observed, are trouble.