Shower faucet stiil drips, despite new washers, stems, etc:

January 12, 2013 9:55 AM

We have a shower where both the faucets drip. We have replaced internal washers, and replaced stems. Replacing either one helps, but not perfectly (usually there's still a slow drip after fixing). The drip gets worse over a period of weeks until it's nearly a trickle, at which point we take the faucets apart and do it all over again. It's gotten a little bit boring.

We've bought new stems a couple of times. They are the closest we can find (Kohler 6N-2 for any experts out there), but they are not EXACTLY the same size as the original (sub millimeter differences in a couple of places). I believe this is in fact the same model as the original, and the differences are not supposed to be important--but maybe they are.

The new stems come with O rings. The O ring always has to be removed to get the new stem to fit into the housing. If it is left on, either we can't thread it at all, or it threads, but then the stem has too much friction to turn. This seems wrong. Still, removing the O ring works far better than leaving it on.

If you're not a plumbing expert, you might still have new ideas on where I can get help with this. Here's where we might go next:

1) Call a plumber. If it would actually fix the problem permanently, I'm happy to call in an professional. However, I'm not convinced a random plumber will do any better than put in a new stem, fiddle with it until it stops dripping for the day, and four weeks later we're back where we are now.
[Or, don't call a plumber, but call a general contractor or a ??? instead.]

2) Take examples of stems and washers to a specialty plumbing store and hope we can find someone who can tell us what the underlying problem is and how to fix it.

3) Something else.

Thanks for advices.

posted by mattu to home & garden (13 answers total)

Have you tried repairing the faucet seat?
posted by squeak at 10:12 AM on January 12

Have you replaced the seat(s)?
posted by dilettante at 10:14 AM on January 12

Taking those O rings off is almost certainly the issue. Finding an exactly fit would be the solution.
posted by Kid Charlemagne at 10:31 AM on January 12

I bet the faucets are internally damaged and replacing them entirely would cure the problem - and would probably be the only cure, which replacing internal parts separately won't. We had the same problem, caused by particles of our rusting iron pipes scoring the faucets internally.
posted by anadem at 10:43 AM on January 12

Seconding dilettante. There may be damage to the seats that contact the parts you've been replacing. They may be replaceable or may not, depending on the make & model. This is where a good plumbing supply store becomes invaluable. I'm lucky to have a great one nearby, and for the extra dollar or two per part over the big box hardware stores, they've saved me many hours of frustration with their great advice when tricky situations have arisen.
posted by gimli at 10:55 AM on January 12

I didn't know about the faucet seat, good idea. I don't have a replaceable seat like the one shown in dilettante's link. I am not sure whether the plastic bit at the end of the stem is therefore considered the seat, or just the edge of the pipe where the stem inserts. I don't think we're missing a part, since the stems barely fit as is.

There's some barely detectable roughness at the edge of the pipe, maybe this could be polished out. There's also a jagged hole in the pipes (both hot and cold sides!), a little ways away from the interface surface, both appear to have been patched with a weld on the outside of the pipe.

I've got pics if anyone is curious.

I think my next stop is a friendly plumbing supply store. If that doesn't work I suppose I'll have a plumber redo the whole thing from the wall out, if he can do it without destroying the entire shower enclosure.

Thanks everyone.
posted by mattu at 12:19 PM on January 12

I'm not sure what they are called but I know they have these grinder tools for smoothing out faucet valve seats at Home Depot in the plumbing aisle.
posted by any major dude at 1:16 PM on January 12

I have found that the washers available in the home centers to be somewhat lacking in material quality. Try an actual plumbing supply company. If you still have the original stem and washer, bring that along.

If I understand my faucet mechanics correctly, the flat washer is what seals the water when it is off. The o-ring seals the stem from leaking when the faucet is on. Prior to o-rings, the nut was packed with waxy string like stuff and then tightened down.

What sounds like is happening is that the washer is too thin. They get compressed during their initial usage period. Each time you close it, it gets smushed a little more until finally it can't hold the seal any more. If you use a thicker washer, or even double up on them, you should find that it starts to behave itself.
posted by gjc at 2:14 PM on January 12

There's also a jagged hole in the pipes (both hot and cold sides!), a little ways away from the interface surface,

That sounds like a rough, as-cast surface. It's rough because of the casting method, left that way because it doesn't matter.

gjc, this isn't an old-style valve with a washer and packing nut. Google the part number the OP included up above. Given that it's not such a valve, I'm not clear what washers the OP might've replaced.

Pics would definitely help.
posted by jon1270 at 5:14 PM on January 12

Yeah . . . that jagged hole I thought was strange is how the water gets to the shower head. Heh. Here's a pic of the pipe. There's no particular faucet seat.

Faucet Pipe

Here's a pic of the stem showing the contact surface to the pipe above. Inside the white plastic circle is the piston that moves up and down to shut off the water. On the end of that piston is a small black washer which we can often replace and get a temporary drip reduction.

Stem Contact Surface

Here's a side view of the stem. The O ring that I mention above is not shown, but it goes on the narrow part of the stem that connects to the faucet handle.

Stem Side View
posted by mattu at 7:23 AM on January 13

Okay, if I'm seeing this correctly then the white (nylon? PTFE?) surface is supposed to mate tightly against the ring-shaped machined surface visible in the bottom of the opening in the valve body, right? That part doesn't move in the course of faucet operation. When the faucet is on and operating correctly, water goes into the hole in the base of the stem / cartridge, and out the holes around the sides of the cartridge, i.e. when you turn the faucet handle it rotates parts *inside* the cartridge, not the whole cartridge, right? If so, there are two ways for this thing to start leaking through the tub spigot / shower head (as opposed to leaking around the handle, which I don't think yours is doing). It can either leak through the cartrdige, in which case the stem's internal seals are failing, or it's leaking around the cartridge because the seal between the plastic bit on the bottom and the machined metal seat is somehow flawed or loosened. Of the two, I think the latter is more likely. I would make sure the machined seats in the bottoms of the valve body openings are clean and free of burrs, major scratches, hard water deposits, corrosion, etc. And then I would turn my attention to making sure the cartridge is being firmly seated against that seat and is not somehow loosening during use.

One thing that might be a contributing factor: in the cartridge side view, it looks like you've been using some teflon tape in a place it doesn't belong. The seal there is made by the large o-ring, not the threads themselves. The teflon tape may be getting in the way of tightening the fitting properly, or its slipperiness may be encouraging it to loosen during use.

Also, you said this stem isn't a perfect match for the original. If the shape of the plastic bit on the bottom is different from the original, so that it doesn't mate cleanly with the machined seat, I think you're bound to have ongoing problems.
posted by jon1270 at 8:23 AM on January 13

Sometimes it does leak around the handle, which is fixed by applying the teflon tape you saw. Maybe we just need to tighten down more instead so the o-ring seal is tighter. Your idea of slipping over time is interesting.

For the rest, very nice analysis. I'll see about smoothing out that little roughness I mentioned.

Thanks for all your help. This was my first Ask MeFi, this place is great.
posted by mattu at 9:09 PM on January 13

Leaking around the handle may be due to failure of the larger O-ring, or the lack of the smaller one. To get it to work without removing the small O-ring, try lubing the O-ring / smaller part of the stem with faucet grease (AKA petroleum jelly) before slipping that threaded cap down over it.
posted by jon1270 at 3:12 AM on January 14