Old Taper Gas Valve Leak? Black iron pipe repair

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Hi all - this old taper gas valve had a tiny leak when we bought the house and was "fixed" before moving in. I was doing some unrelated work down here and decided to spray some gas leak liquid on it and has it showed very very small microfoam being produced out the side with the red arrow (see picture) where the threaded nut fastens to the threaded stud. Located in unfinished portion of the basement, feeding the gas furnace to the right side and the kitchen to the left side (where the valve is). Honestly I never plan on using it, I always just use the whole house shut-off at the meter.

1) Is attempting to tighten this (packing?) nut safe - ie: is there any chance I'm going to make it worse?
2) Is it safe to put some silicone/RTV (or JB weld?) around this leaking threaded area to seal it temporarily? (see pictures, red arrow)
3) What is the recommended permanent fix here? Cut pipe A (see picture) in half, un-thread, install new gas ball valve with black iron pipe union? L-R coupling and nipples? Are unions code for gas lines? (Greater chicago area). I will likely hire this out but ultimately I'd like to know the recommended method here.
4) Since I'm never planning on using it - is repacking it with grease and tightening it hard a permanent solution? I don't ever plan on turning it - I'll use the whole house gas valve.

As I type this post, I went down again and sprayed more liquid - this time, no foam/bubbles at all... It must be a very small leak??? I've never smelled anything down there.

Any advice is greatly welcomed.





Licensed plumbing contractor
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San Francisco Bay Area
tightening within reason is ok.
micro leak is ok
unions are allowed in permanently accessible locations in most jurisdictions and can leak.
we use right/left nipples and couplings if there is room to put in a modern valve when possible and needed


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Peace valley missouri
When tighting or loosening that nut put a hold back on the handle. I haven't had very good luck with that style of valve. That pic with A on it looks like that is 1" pipe reduce to 3/4" at valve. Could cut the 1" nipple in half, pull valve and the nipple screwed into the tee. 1" x 3/4" bushing, 3/4" coupling, 3/4" union and few 3/4" nipples all black pipe.
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