Leaking shutoff valve

[John13]

I just replaced a toilet shut off valve that screws on to what appears to be a 3/8 galvanized pipe. I have applied Teflon tape to the threads and tightned it but still get a slow drip between the threads of the pipe and the nut on the valve. I don't want to break the pipe by overtighning it. The old valve was an angle stop one with a multiple turn. I had a hard time finding the new 1/4 turn 3/8 x 3/8 as many stores just carry standard 1/2 x 3/8. Should I take the new one off,apply thicker plumbers tape or do I need to get an adapter so I can cover more of the pipe threads. The current shut off valve does not cover some of the threads on the galvanized pipe. Thanks.

 

[havasu]

I don't like Teflon tape on threaded parts such as this. I would rather use Rectorseal #5, which is a lubricant for a tighter seal, along with stop leak abilities.

 

[Twowaxhack]

The threads of the nipple could be cracked, especially if it’s old brass.