Water pipe union

[Foggy]

I have a brass faced union that I cannot get to seal. Tightened to the point that I fear something will break. [Standing on one pipe wrench with a pipe on the handle of the other wrench]. Should I try some pipe dope on the brass faces?

[Bob10]

I don't mean to be a smart butt but did you check if something got caught up in between?  piece of hard water build up or something between the loose nut and piece under it

[MikeBob]

I would give it a try, nothing to loose.

[blackhat]

Brass faced? Solid brass, galvanized steel or black? Solid brass would be the best choice. As Bobski mentioned, make sure the sealing faces are clean and not scored or pitted. They can be cleaned with fine grit cloth or scotchbrite. A bit of dope on the nut threads will make it easier to tighten and later remove.

[Foggy]

Galvanized steel with brass faces. Faces are clean. Pipe dope on the threads and the non-threaded half where the nut comes against it.

[Wild Turkey]

Is it a new union?  Are the threads clean all the way?

I'd take it apart and see if the "nut" would go all the way to make sure there's nothing in the threads to stop it short of full tight.

[blackhat]

The pipe needs to be aligned, a few degrees of deflection can cause leaks, as can a mismatched union ( you shouldn't swap parts ).  A thin rubber gasket can be fitted but if this is part of the electrical ground, put a jumper around the union.

[therick34]

The pipe dope could very well be your problem. A little errant dope on the mating surfaces could keep it from sealing. The same issue occurs with flare fittings on soft copper when folks feel compelled to apply pipe dope where it isn't needed.

Rick

[MikeBob]

The pipe dope could very well be your problem. A little errant dope on the mating surfaces could keep it from sealing. The same issue occurs with flare fittings on soft copper when folks feel compelled to apply pipe dope where it isn't needed.

Rick

I dont that was in the original post, it was a suggestion for a better seal.
Heck my plumbers put it on the rubber ring between the toilet tank and toilet bowl, on all sides.
,

[A Squared]

...and make sure you put some teflon tape on the threads.