After 14 years, the hot side of the bathroom sink faucet was leaking
badly around the stem, although it still worked fine otherwise (and did
not drip).

Finally got round to repairing it. It is made by American Standard,
and appears to be 2904-line ("Williamsburg") or the like, which use
Moen-style replaceable valve cartridges (the patent is long expired).
For this faucet, the correct kit is item 028610-0070A "Cartridge Kit".

Installation was quite easy, but the suggested adjustable wrench is a
bit clumsy to use because the hex flats are shallow. What works
perfectly is a 22mm 12-point box-end wrench. Right-hand thread. One
has to readjust the stop on one cartridge to allow the valve handles to
line up correctly.

After finishing, I took the old hot-side cartridge down to the shop for
an autopsy. The cause of death was that the hot water had over the
years washed the grease out of the stem seal (two O-rings side by
side), allowing the O-rings to wear and become loose. It is impossible
to re-grease this seal without destructive disassembly of the
cartridge, so one just replaces the cartridge, which costs $25 from the
local plumbing supply house.

Now, this cartridge has quarter-turn ceramic-disk valve seats, and
these show no signs of wear whatsoever. So all that advertising about
the seats lasting a lifetime are true, albeit misleading - the
cartridge will die far sooner. Not that $25 every ten years is so bad.

American Standard and others are now touting diamond-coated
ceramic-disk valves as being even better, but I wonder if they solved
the hot water washout problem. I guess I'll find out - I just received
the new kitchen faucet, which has the diamond coated ceramic seats.

Joe Gwinn