captain
Contributor
Drain it out and pull the valve off.
Those 1/2" holes are a little harder to look in, but take a flashlight and peek inside the best you can. Move the light around along with your eyesight line and look around the bottom of the tank and see if there are any rust spots or pitting.
I'm not the right one to ask about pitting since I just murdered a perfectly good tank and am still suffering great remorse for my inexcusable actions, I should be locked up for what I did.
But anyway, with the death of one tank comes the rebirth of another great tank. I just got a 1960 72 1/2" valve, it needed a shot blast ($24.75) and a hydro ($18).
It also needed an updated burst disc ($12.99) and now I have another great 72 in my fleet.
If your valve has one of the old style burst discs (they're flat with a hole in the center and slots for a flat screwdriver) you'll need to remove it and replace it with a hexagonal nut type with three holes on the sides of the hex nut.
Most shops won't fill tanks with the old style burst discs. Be really carefull trying to get out the old one, the flat screw driver part strips out really easy and if that happens you'll need to surgically remove the old burst disc nut without damaging the threads. It's pretty hard but I've done it. It requires a drill or a dremel tool, a steady hand, some pick tools, and a lot of patients.
Good luck and congratulations!
The 1/2" valves require a good vise and the proper wrench and procedure to remove and install without mangling the valve.
If it is an original burst disc from 1960 it would be the hex with a lead plug in the center. Once the valve is out of the tank a little heat on thr plug from a propane torch should loosen it if it is frozen without resorting to surgery.