Need some plumbing help.

[Jerry Simon]

I've got these tiny, pinhead size black specs/residue on my white acrylic bathtub surface after use.  When I wipe them off, they smear like tar.  I believe it's some sort of deteriorating rubber residue from a pipe or a faucet, or perhaps my water heater.  Bled my water heater, and no sign of residue.  Unless/until I get some other good advice, hopefully here, I'm going to replace the tub faucet cartridges where perhaps their deteriorating O-rings are the culprit.

Having trouble, though, knowing how to pull the cartridges; unlike others I've done.  Two handle tub faucet, and once the handle is removed, I've got a notched, threaded tube, and same has a metal base ring that appears to be threaded onto the notched tube.  Pinkish stem sticks up the middle.  Inside the pinkish stem is a phillips head screw.  How do I proceed?  Screw removal and simply pull the cartridge (doesn't seem right. . .)?  Unscrew the notched tube?  Unscrew the tube's base ring (the one the screwdriver in the picture is pointing to)?

Any and all help is welcome, and any other thoughts on what might be the source of tub surface residue.  Happens every time tub is used, but only in past few months.   Water heater is only about two years old, though I read the sacrificial anode might be the culprit?   Water heater is piped with copper, not flex.  Thanks for any help.

Edited April 5 by Jerry Simon
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[hausdok]

Sometimes, the interior surface of copper develops a black oxidation that sloughs off. I used to see that when turning on fixtures that hadn't been used. The black stuff would coat everything. My wife would wipe whatever it was down because it smeared. Seemed only to happen when a place was plumbed with copper.

[Les]

I go along with Mike on the copper.  Soft copper tubing does not oxidize but ridgid does when left stagnant with treated water;  chlorine, salt, potassium permanganate or even activated charcoal filtered.   the configuration of faucet is something i have never seen. 

 

[Jim Katen]

In the deep recesses of my mind, I recall something that Mike Casey wrote about this. Sadly, I don't remember the details, but I think it had to do with chlorine attacking the rubber on valve washers and O-rings. 

I'm also unfamiliar with that valve configuration, but I'd start by unscrewing the Phillips head screw at the base of that plastic stem and see if the valve comes out from there. 

[Jerry Simon]

2 hours ago, Jim Katen said:

In the deep recesses of my mind, I recall something that Mike Casey wrote about this. Sadly, I don't remember the details, but I think it had to do with chlorine attacking the rubber on valve washers and O-rings. 

I'm also unfamiliar with that valve configuration, but I'd start by unscrewing the Phillips head screw at the base of that plastic stem and see if the valve comes out from there. 

Yeah, I'm thinking O-rings also.  After messing with water heater and the faucet valves, a couple bigger chunkers of black stuff came out the hot side.

I did unscrew that plastic stem, and it was an extension of the cartridge's top stem.  Cartridge was being held down by a plastic ring which screwed down the inside of the threaded tube (tube threaded inside & out).  Once I got the ring out, seemed to be a matter of simply pulling the cartridge up and out.  Wouldn't budge though with a needle nose, and not wanting to risk mangling the top of the cartridge's plastic stem any more than I already had, I gave up.  Don't want to risk cartridge damage until I have a new compatible one onsite.

Any thoughts on pulling a stubborn cartridge?  (Plumbers are so darn expensive, but might be time. . .)

 

[Jim Katen]

If you hire the plumber and watch him work, you can write off the cost as "education." 

[Jerry Simon]

A shout-out to Moen.  Talked with their warranty dept., and they're sending me replacement cartridges, a replacement tub spout (as aerator ring may also be deteriorating), and a cartridge removal tool, all FREE of charge (others are selling removal tool alone on-line for $24.00 or so)!

Spent maybe 5 minutes total on the phone with service person.  Made my day.

Edited April 25 by Jerry Simon

[Les]

Great!  I had a similar experience with Delta couple months ago.  Patience, carefully chosen words, and a smiling telephone voice!

[Steven Jones]

It sounds like you're on the right track with the faucet cartridges. To remove them, start by unscrewing the notched, threaded tube (the one with the metal base ring). Once that's off, the cartridge should come out easily. As for the residue, deteriorating O-rings in the faucet are a strong possibility. If replacing the cartridges doesn’t solve the issue, you might want to check the water heater’s sacrificial anode just in case, as it can cause similar problems if it’s wearing out.