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Stripped Rad Nut

I had my radiators powdercoated over the summer. While they look great, on one unit the gorilla that reinstalled them seems to have stripped the brass nut that connects the radiator to the valve. This is an 85-year-old single pipe system. Previous attempts to remove a spud from a rad was an exercise in futility (and frustration and skinned knuckles). Is there a replacement solution for this? I'm thinking of something like a two-part nut held together with hex bolts. Duct tape? I'm out of ideas and tired of waking up with water on the floor.



  • TomM
    TomM Posts: 233
    union nut?

    if the threads on the nut are stripped, you have to replace the whole spud thingy.  If the nut is cool, and the male threads on the valve are stripped, maybe you can get away with just replacing that side of the valve.


    anyway, my favorite method to remove the spud thingy is thus:

    -put on safety glasses

    -clamp the union nut with vice grips

    -cut off union nut with cutoff wheel or use sawzall

    -now that the union nut is off, put the sawzall blade into the spud thingy pipe, and cut it vertically, while being careful not to damage the threads inside the radiator.

    -flip over sawzall and make a cut in the vertical up direction with same method as above.  again, try not to cut the threads inside the radiator.

    -use a cape chisel and engineers hammer to bang out the 'cut in half' spud thingy pipe.

    -retap the radiator female threads with proper size tap

    -use lots of pipe dope, preferably hvac blue high temp, and install new spud thingy pipe union and valve.

    -clean up

    -sit back and enjoy new radiator valve.  Contemplate what the real name is for the 'spud thingy pipe'.  I would suggest using all the same brand in all your radiators so you can use extra parts later.
    beautiful Conshohocken PA
  • 'spud thingy pipe'

    Great description of procedure.

    BTW- That part is known as a "union tail-piece" ;-). 
  • JimmyR
    JimmyR Member Posts: 5

    I'll give it a shot. A little nervous about having to re-thread the radiator.

    One of the many joys of owning an old house.
  • Mike Kusiak_2
    Mike Kusiak_2 Member Posts: 604
    Radiator threads

    If you are careful you may not need to rethread the radiator, just clean the existing threads. The trick is not to cut completely through the tailpiece pipe, but just enough to barely expose the peaks of the female radiator threads. Once the tailpiece is so weakened it will break into halves when hit by the hammer and chisel.

    If you are able to cut the union nut off without damaging the tailpiece, you may be able to get a pipe wrench on the end of the tailpiece and unscrew it. If it is stuck and collapses or breaks with the wrench you will have to resort to cutting and splitting as described above.
  • TomM
    TomM Posts: 233

    union tail piece!  another one of life's mysteries solved.  thanks.

    mike- thanks, i forgot about the possibility of getting it off with a pipe wrench after cutting off the union nut.
    beautiful Conshohocken PA
  • Mike Is right-on,,,,

    sometimes you can use a hexagon-shaped(tight fitting) cold chisel, this will help engaging the internal TP gibs and help prevent distortion.
  • JimmyR
    JimmyR Member Posts: 5
    Upon closer inspection

    It looks like the union tail piece nut is not stripped (tip of the hat for the name of that part) but the valve has been bent. I bought a new valve assembly and stuck the shiny new UTP into the old valve and the old part is clearly out of round.

    Mounting the shiny new valve on the old UTP seems to go smoothly.

    Can I mix 'n match the new valve with the old UTP or do I need to replace both to assure a tight fit?

    Also, will applying pipe dope to the tail piece help over the long run or only hide any potential leaks for a short while?

This discussion has been closed.