Valve thread/steel tank

[jimyoungdd]

Got back 20 yr old steel 98 from hydro. While away I rebuilt the valves that go the
set of doubles.
Issue is one valve makes 4, 5 turns (about 1/4 to 1/3rd) the way in and starts to
get difficult to turn. (no issue taking them off)
I've ck the valve threads and they look ok. I used a thread stretcher for a few minutes
and it did not seem to help.
I can say without reservation the issue is not with the tank.

Can I simply try and put some more pressure on the valve and see if it goes on?
Meaning the brass valve should conform to the tank opening. I know I should not
take a hammer to it.
I have 2 days to fix this issue.
Tks,
Jim

 

[captain]

I assume you are trying to screw it in by hand. Sometimes it takes a wrench to overcome the drag. If a 10" cresent wrench and mild force won't get it pass the drag point you have a larger problem with the threads.

 

[The Chairman]

Try three tiny dabs of Christolube on the threads... 120 degrees apart. Either you have a deformed tank thread or valve thread... try to put the other valve in this tank and vice versa. That should help you to isolate the real issue.

 

[jimyoungdd]

I'll try the c-lub. It is the valve.

 

[jimyoungdd]

Hi Captain.
Hoping to get this ans. I'll add some c-lub and try your suggestion.
Got nothing to lose. If it does not hold gas maybe I can get it the valve retreaded.