Rusted galvanized nipple threads HALF broken off in diverter

[Mr. Lahey]

My 1950's era ranch had a leaky diverter valve - about half the water would come from the tub spout vs. the shower head when the diverter was engaged. Intending to replace it, I attempted to unthread the diverter first by hand, and then with a pipe wrench, with a piece of leather to avoid marring the diverter.

The threads on the inside-end of the galvanized nipple (3/4" NPT, about 3.5" long) sheared off, due to severe corrosion. Now I'm left with a partial set of clean brass threads on the top of the inside fitting, and another clump of rusted steel locked into threads on the bottom.

I've already tried picking and jabbing to see what comes loose - not much. I don't think that a nipple extractor would work, because it would bite into the exposed brass female threads first.

Any ideas before I tear open the wall from the other side? I'm hoping to keep the pink tile - getting rarer these days!

Also, the inside brass fitting appears to have two passageways. It looks like a regular threaded elbow, but there are clearly two holes inside. Is anyone familiar with this tub/shower valve? I don't see any manufacturers marks on anything. My guess is that the hot and cold water come from the top, and get pushed back through the bottom passage, to the shower head.

 

[Marlinman]

That is a twin elbow and your guess is correct. As bad as the corrosion is I would start with a 3/4" pipe tap.

 

[Sponsor]

 

[Mr. Lahey]

Thanks Marlinman. I'll see what I can do with a tap. Another challenge is that the fitting is about 3" deep in the wall - I'll have to make sure that any tap is long enough, and doesn't fall down into the wall when it inevitably slips for some reason.

The twin elbow photo looks exactly right. I can't figure out what advantage it would offer over a simpler cross-shaped setup using standard single fittings. A major disadvantage is that it can't be removed without removing the shower riser, which means I'll have to bust up the wall up to the shower riser at least...

 

[hj]

Its "advantage" is that it does NOT cause the tub water to come out of the shower head, until the diverter button is lifted. Have you tried inserting a 3/4" nipple into the twin ell? THere do not seem to be enough, if any, remains of the nipple to keep it from screwing in.

 

[Mr. Lahey]

Hi hj, thanks for your thoughts.

I've now read up on the twin-ell and understand how it works. If I replace, I may choose to add a third handle for a manual-control shower diverter. I don't like that the twin-ell creates a restriction to the flow.

I was able to screw a new 3/4" galvanized nipple into the brass fitting about 1-1/2 turns before it got hung up on the corroded bits. I did this by hand. I haven't tried to force it with a wrench, but that might happen today.

I've also ordered a 3/4" tap to see if I can cut out the rusty junk. I'm not very optimistic about this - the twin-ell internals will stop the full engagement of the tap cutters. Also, I'll have to weld a longer stem onto the tap, because the fitting is about 3" deep into the wall. Fun stuff!

 

[Reach4]

I've now read up on the twin-ell and understand how it works. If I replace, I may choose to add a third handle for a manual-control shower diverter. I don't like that the twin-ell creates a restriction to the flow.

It does not add significant restriction to the flow. Its magic is that any restriction that occurs before this fitting does not matter. So any discussion of restriction are probably trying to make that point.

I was able to screw a new 3/4" galvanized nipple into the brass fitting about 1-1/2 turns before it got hung up on the corroded bits. I did this by hand. I haven't tried to force it with a wrench, but that might happen today.

Use galvanized for sizing, but use brass for your actual assembly.

I've also ordered a 3/4" tap to see if I can cut out the rusty junk. I'm not very optimistic about this - the twin-ell internals will stop the full engagement of the tap cutters. Also, I'll have to weld a longer stem onto the tap, because the fitting is about 3" deep into the wall. Fun stuff!

There are different types of tap. A bottoming tap could be useful if the tap you got does not go deep enough. However the one you got might be quite enough.

Also, if you use more PTFE tape when you assemble, the nipple will not go in quite as far.

While doing this, you might want to consider replacing your spout. The mid-priced and upper priced Deltas mostly dribble a lot less than most diverter spouts.
Delta Faucet RP17454 Tub Spout Pull-Down Diverter, Chrome (which I have) (RP17453 is same but plastic, so won't corrode if that is a problem with your water) RP5836 similar but adapter RP33794 has set screw. https://terrylove.com/forums/index....d-cant-figure-out-how-to-turn-on-shower.7595/ discusses a quirk. There are others that have a pull-knob that cost more.

I don't know if there are Delta diverter spouts that dribble like the common ones.

 

[Mr. Lahey]

Thanks Reach4,

I will be replacing my spout for sure, the old one is still stuck to the old galvanized nipple, and it was extremely leaky in any case.

I was using this old discussion for learning about twin-ells: https://terrylove.com/forums/index.php?threads/what-does-a-twin-ell-do-that-a-tee-cannot.35287/

I'm using a galvanized nipple to see about clearing up the threads. I'll install a brass one for the final installation, assuming I don't have to tear out the whole thing. I figured it would handle the abuse of the rusty threads better until I got things cleaned up. Also, an 8" galvanized nipple is a lot cheaper to use as a tool than a brass one.

 

[Reach4]

I see your point on restriction.

 

[Mr. Lahey]

Hello all. I wanted to update with the successful outcome of this project.

I bought an Irwin 3/4" tap and made an extension for it using an 8-inch 3/4" galvanized steel nipple. The hole in the tile fits closely around the 3/4" nipple, so there isn't any room to grab the tap with a normal tool. I used a 4" grinder and cutoff wheel to grind slots down the nipple so that the square corners of the tap could fit inside the nipple. Then I added a 3/8" hole at the other end so that I could add torque with a screwdriver. It worked great! I tapped out the rusted threads and removed any loose material.


Then I installed a new 4" brass nipple with an internal cam-action pipe wrench, using PTFE tape and a little pipe dope. I got probably 5 turns on the nipple. I installed a cheap spout (plastic Danco from Home Depot) for testing purposes. I was able to cut an access hole in my basement ceiling so that I could see up to the in-wall nipple/fitting to inspect for leaks. No leaks so far!

Any recommendations for a brass or other better-quality 3/4" spout? My new brass nipple protrudes about 5/8" from the finished tile wall.

Thanks for your help, forum members. Hopefully my photos will be helpful to someone else in the future.