Shower arm (?) Leak

[siskin]

Hi there,
As it is almost always the case, for us amateurs, I have a leak in the shower, water in, but it hides from me.
I noticed a leak after about three months after I built the shower and located it where shower arm screws to the in wall brass connector (pic). I attributed the leak to shower arm (10 inch L shape) not being tightened well. Over the next month I tried to use brass pipe extension with coupling for shower arm, good teflon tape, etc. Always leaked, sometimes less, sometimes after a while.
Finally, I sadly proceeded removing the tiles and after that I connected the shower arm, let it run for 15 minutes and NO leak anywhere. I did the plumbing myself, flex pipe. I was surely hoping to see some connection inside of the wall srewed up, but they stayed dry.
Sure, I can re-plumb that part in the wall, but I am not certain.
I have Grohe valve with two outlets (the other one for hand shower is fine), so I eliminate trouble with the valve. Shower is on the second floor, above the garage, and I have an access in the ceiling.
So I thought I will ask, maybe I am missing something, forgetting something, I just dont want to replumb the connector for shower arm.
Pic is the connector in the wall.
Thanks for your thoughts.

 

[phishfood]

Put a 1/2" pipe nipple with a cap on it into the wingell, and turn the pressure on. If there is a problem with the connection in the wall, it should show up.

 

[siskin]

Thank you for an advice. I truly appreciate it. I did as you said, sorry it took so long, other projects got in a way.
Anyhoo, put a brass cap on, the first one from HD had a micro hole on a side (lovely), but now the cap is on, water on and no leak.
I am still kind of afraid to retile, I simply dont trust it.
Thanks again.

 

[phishfood]

Applying static pressure in the manner I described will put a lot more pressure against the in wall fittings than will be applied to them with a flowing shower head.

It is rather common for the thread joints to leak when installing a showerhead. I fixed one just last week.

 

[Matt30]

Use pipe dope in conjunction with the teflon tape to seal the threads

 

[frodo]

my opinion. play doll dress up with the teflon tape, when done, throw it away

get a can of rectoseal # 5

i put my chanel locks handle into the shower head nipple. and use them to tighten up the nipple

 

[Matt30]

You guys and that rectoseal stuff is like Franks Red Hot Sauce. You put that **** on everything!

 

[frodo]

i even use it when i solder copper. if you do not want the solider to stick to a thread,

dope it,

 

[Matt30]

We don't have rectorseal5 here as far as I know. Trusty teflon and pro dope

 

[phishfood]

Blue Teflon and #5 for me. Since I have started using that combination, I am sure I have had a leak on a threaded fitting, but I haven't found out about it yet.

Is that disclaimer going to be enough to keep the jinx off of me?

 

[siskin]

Hi guys,
Thanks for all of your comments and advice.
I capped the pipe for a month and no leak. I installed the arm with good teflon and dope. Tried it, no leaks.
Rest of the family came back from long vacation and leak showed up again after three showers in a row. No clue. Waited one week doing nothing, again three showers in a row and no leak.
If you are thinking a leak around the drain or base, I tried that with no leak.
I tried using only the hand held shower that has a separate connection from the "faucet". I figured that if there is no leak using the hand held, the problem must be in the "main"shower water circuit.
Bu it stayed pressurized for a month without a drop.
I am thinking a faulty faucet leaks when opened... Sorry, I am really puzzled.
Help is much appreciated, before I tear everything down .