Valve leak

John_Chapp13

The radiator in my soon to be born kid's room has a small leak by the valve (a paper towel gets moist by the end of the day). I replaced the old valve with a new one, cleaned the bushing with steel wool, and the leak remains @ the spud. I tried just pipe dope on the threads as well as teflon tape + dope most recently, along with properly pitching it, and it hasn't helped. I fear I may need to replace the bushing? It looks a little stripped inside. Any thoughts on what to do? Other note: the pipe in the floor is copper which I am told is strange and it needs to be pulled up a bit to reach the spud, could that downward pressure be causing the leak?

Jamie Hall

Oh dear. That connection is a union, and the seal is intended to be between a machined face on the end of the valve, and a corresponding machined face on the spud coming out of the radiator. The threads have nothing to do with it, except to hold the thing together mechanically.

You will need to take it apart -- undo the big nut completely -- and shift the radiator to the right so you can inspect the two faces. They must be perfectly clean and smooth -- no knicks or scratches. You can try cleaning them with a fine brass brush or very fine emery paper -- but nothing harsher. If there are knicks or scratches, you may have to replace both the spud and the valve, since they are matched. Once you are sure the faces themselves are clean, make sure that the valve and spud are aligned as closely as possible -- both horizontally and vertically and angularly -- and push the spud and the valve together. Then use the nut to keep them that way. Don't be a gorilla, and don't try to seal the threads.

AdmiralYoda

Is it leaking at the radiator/spud connection or between the spud and the valve inside the union?

Like @Jamie Hall said, the faces between the spud and the valve are machined and need to be perfect to seal right.  The threads at the spud/valve union are only there to tighten the faces against each other to provide a seal.

John_Chapp13

It's leaking at the spud-radiator connection, not at the union. This is a brand new valve and spud that is leaking just like the old one. The only thing funny about the connection with the valve is I need to pull the valve and pipe up (it moves) to reach the radiator spud height, so there is some natural downward pressure once it's connected. But the connection is firm and the valve and spud clean.

ethicalpaul

What sealant are you using on the spud? I'm a little shocked it's leaking there--there are lots of threads and you can really torque that brass spud into there (in my house anyway!).

I just use teflon tape for mine, like 6-7 turns

John_Chapp13

@ethicalpaul there is a few turns of teflon tape as well as Megalock thread sealant. Previously I tried just the sealant.

John_Chapp13

The spud is torqued in there as far as it can go before I snap it. I am wondering if those bushing threads are too corroded?

JUGHNE

The rad threads look a little tough.
After brushing the female threads of the bushing, you could get an iron nipple of that size, and run it in and out to clean up the threads. You can pipe wrench on the iron pipe more than you would get with the spud wrench on the brass.

ethicalpaul

The next question might be, what pressure is your system running?

pecmsg

Try getting a tap and cleaning up the threads.
I like never seize on the union rather then pipe dope or Teflon.

mattmia2

Are you using a spud wrench for the spud? You could get some ball wicking and wind a strand of that in the threads.

PCapNJ

I had this happen to one of my radiators when I got a little too confident with my sawzall doing the nipple collapse method for replacing the spud. What worked for me was the lampwick, and pipe dope. Video below explains it a bit better.

Fast forward to 7:15

https://www.youtube.com/watch?v=pFDw4kfaPu4

John_Chapp13

@ethicalpaul looks like 1.4 PSI

John_Chapp13

To clean or tap the bushing threads, do I just buy a 1" iron nipple (the valve is a 1")? I'll try the wax thread too, that's a good idea.

JUGHNE

The best thing you could do is as Pecmsg said, rent or borrow a 1" pipe thread tap. If you get one just go in and out a few turns at a time to clean the threads, do not go too deep as to start cutting new threads.
The try with the iron pipe may be enough but will not clean the threads up as much as an actual tap.

EBEBRATT-Ed

@John_Chapp13

Clean up the threads as best you can. Use teflon and dope and wax thread is fine.

The fix is to put some dope on the inside threads of the bushing.

When you thread in a nipple or spud if you notice a lot of the dope gets "pushed out" and never gets inside the joint. Many cans of pipe dope in there instructions on the can (Rectorseal True Blue is one) that recommends doping the inside threads on pipe 1 1/4" and up. I know yours is 1"

Many on here will rail against doping the inside threads. I have fixed many leaks with this method

John_Chapp13

Dope on inside threads + Teflon tape + lamp wick looks to have worked. Thanks all!

Joe_Dunham

There's a product called Xpando. Its a powdered dope you mix with water. It expands as it dries. Google it. Not Amazon. Permatex may work also. Hope there's no crack in the cast iron