American Standard bathroom faucet ceramic cartridge issue

In one of our bathrooms we have two American Standard "Willamsburg" faucets (2904222.002). These have ceramic cartridges. Since purchase in 2000 several cartridges have leaked and needed replacement, with the hot failing about twice as often as the cold. (Iffy statistics - small sample size.) Anyway, recently one of these cartridges rapidly went from a drip to a fast drip then to a stream. Replacement cartridges are in the mail from A.S. but in the meantime I removed the bad cartridge and stuck in one of the previous failed ones - better a slow drip than a steady stream. (Shut off under the sink doesn't work and I don't want to touch it since it and the pipe it is attached to are 70 years old.) These cartridges have a soft rubber ring around the bottom. On removing the failed one it left chunks of that rubber stuck to the brass in the "valve seat". (Not sure if that term applies for cartridges.) Scraped off most of it with a toothpick but a rubber film was still visible. What is a safe way to remove this stuck on rubber without damaging the flat brass area?

The ceramic valves in the previous failed cartridges never looked like they had any problem, no obvious nicks or cracks. Conversely, on looking at these cartridges now, they all seem to have the rubber ring on the bottom chewed up to varying extents. If that bottom ring leaks does water go around the bottom and up above the valve to leak out the faucet? Since water in our area is notorious for eating copper pipes I suppose it is also possible that it slowly chews up that sort of rubber. Makes me wonder if there might not be some thin type of washer which could be placed under one of these failed cartridges to seal it to the seat for longer than the built in washer. It would have to be quite thin though, since the threads for mounting the cartridge are only a couple of millimeters high. I tried a black rubber washer about 3mm thick (from an assortment of washers kit) and the cartridge threads could not screw in far enough to seal. Turning on the cold side sprayed water out the threads (the hot was of course off at the time.)

The rubber ring on the bottom is likely getting damaged during installation.

Always clean out any sediment, minerals, rust, or crud from any valve body before installing new guts into it.

A thin wadded up rag soaked in vinegar or CLR will clean up most of it.

Then flush with clean water, don’t leave any lint or crumbs in there.

Then coat the rubber parts that will be resting against the valve body with a thin layer of plumbers’ valve grease, which you can find anywhere.

So the rubber is able to more easily scoot around as it is being tightened up against the metal valve body.

This is a silicone grease.

DO NOT USE VASELINE, it destroys some types of plastic and rubber.

Also, any tiny crud you leave in there will get into the extremely tight clearances of the ceramic cartridge, and then will start chewing it up with every twist of the handle.

Minerals and junk from the shutoff valve will also end up there and cause damage.

Before you remove a leaking cartridge next time, remove the faucet aerator and open the valve all the way, while you cycle open and closed whatever shutoff valves you will be operating during the change out, including at the meter if you will be fooling with that also.

This will flush out a lot of the grit that otherwise would end up in your nice new cartridge.

Putting plumbers’s valve grease on rubber parts should also provide at least a little protection from excess chlorine in your water supply, which can eat up soft plastic and rubber.

You could rub off the bits of stuck on rubber with a popsicle stick, or similar thin scrap of wood.

A.S. customer support got back to me and they also said to clean up the area with vinegar before installing the new one. Will do that. They did not suggest plumber's grease but it probably won't hurt so will try that too.

As far as a I can tell every one of the cartridges failed because the rubber on the bottom broke down, allowing water to seep around the valve part of the cartridge, and then out to the faucet. If they had a real washer on the bottom or an O ring around the barrel most likely none of these would have failed. The seal that they do have is incredibly narrow, it is basically a ~1 mm square cross section O ring protruding from the bottom which pinches between the cartridge and the faucet "seat". Not sure what type of rubber it is but it is white (or nearly so) and very soft.

I have replaced the o-rings with hi temperatures o-rings from a kit and a little silicon valve grease. Yes

Yes what?

New cartridges came and were installed. These have black rubber instead of white on the bottom, and the rubber seems slightly wider than before, but it is still the same part number. Lightly greased one and installed on the hot side after thoroughly cleaning the seat area with a bit of cloth soaked in vinegar. It was still dripping, but much less. So replaced the cold side too and the drip went away. Dual cartridge failure, a lot on one side, a little on the other. Interestingly the aerator was now almost completely jammed. Apparently a slow drip of very hard water had packed it up with calcium deposits internally, even though there was no evidence of it on the surface. A two hour soak in vinegar fixed it. We will see how long the new cartridges last.