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Removing union nut / stem for replacement

toddo Member Posts: 3
I recently cracked the union nut on a value on one of my cast iron radiators.

I wondering what the best approach is here to fix it....

I've seen/read on this and other forums that removing the 'stem' is not always a smooth process... any tips? other suggestions? (heat it with propane torch and hit it with PB blaster/WD-40 first???)

I have a new value that came with the 3/4" FIP (or is it MIP?) union nut and 'stem' ( i think it's called a stem...)

The new stem looks too short compared to the one that's on there.

So, my thought was to:

a.) clean, and spray with PB blaster / WD-40 first, then let it sit for a while

b.) heat it with a propane torch for a little (putting some wood scraps under the radiator legs just in case.. to prevent my flooring from getting jacked up)

c.) try to remove the stem - would i buy and use this-> (Radiator spud wrench) <a href="http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeZip=19148&store=&zip=19148&state_1=&distance_1=50&langId=-1&productId=202246292&city=&recordId=4101&storeCity=Philadelphia&latitude=39.926913&longitude=-75.144789&storeState=PA&catalogId=10053&rough=Value&storeId=10051#.UQlRwx19Knk">http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeZip=19148&store=&zip=19148&state_1=&distance_1=50&langId=-1&productId=202246292&city=&recordId=4101&storeCity=Philadelphia&latitude=39.926913&longitude=-75.144789&storeState=PA&catalogId=10053&rough=Value&storeId=10051#.UQlRwx19Knk</a>

d.) take off the old union nut (that i cracked while trying to tighten up a leak)

e.) replace the old union nut with the new one that I got with the 3/4" valve

f.) reassemble with teflon tape, carefully

g.) drain system (it's capped off right now), attach new valve to new union nut (reattach radiator)

Any suggestions otherwise? Tips on removing stem... tools to use?

[ my other thought was to forgo the radiator spud wrench and just crank on the outside of the stem with a pipe wrench.. but i thought i might break more stuff if i went that route..]


  • Slimpickins
    Slimpickins Member Posts: 334
    any luck?

    Just curious if you had any luck. I was going to reply but have been super busy. Let us know.
  • toddo
    toddo Member Posts: 3
    haven't tried yet

    I haven't tried yet, I was waiting for some confident boosters :).

    Also, wasn't sure if my plan was sound....

    I take it that is the right 'radiator spud wrench' i linked to?
  • Boiler wrestler
    Boiler wrestler Member Posts: 43
    Removing spud

    In my experience removing very old spuds, the spud wrench will shear off the internal ears of the old spud and nothing more. It is handy to have to keep your wrench from crushing it after you cut the nut off and put the wrench on the largest part of the spud. You will not be able reuse whats left of the old spud as it may shear off and then you get to learn to peal a nipple. Oh it's good fun.
  • Slimpickins
    Slimpickins Member Posts: 334

    I learned a trick i got here on The Wall on how to get the tailpiece out of the rad after cutting the nut off. Stick a socket that barely fits on the inside of the tailpiece to keep it from collapsing and use your pipe wrench. As far as the new tailpiece being shorter than the old one. If you have play up and down on the riser pipe, check out a Watts 65 angle radiator valve. It has the union on the bottom that goes on the riser and you can use the right size nipple to tie horizontally to the rad. Good luck!. http://www.watts.com/pages/_products_details.asp?pid=687
  • toddo
    toddo Member Posts: 3
    it worked!

    So I was able to get the old spud/tailpiece off, pipe doped the new one, and screwed it back on.

    I didn't reconnect the radiator yet, so I don't know if I have enough play to make up the ~1/4" I'm short by (in comparison to the old spud length).... but we'll find out tomorrow or whenever i attempt to reconnect the rad.

    Here is how I did it (very similar to how i guessed in the original post)

    a.) drained as much water out as i could (lifted one side, while other side of radiator had a cup underneath it).. then laid rad on its side.

    b.) cleaned, and spray with PB blaster. scrapped with flathead screwdriver... tapped with hammer lightly (on the spud)..then let it sit for a while , then repeated process again

    c.) heated it with a propane torch for ~1 min (on the bushing, not the spud)

    d.) Stuck the radiator spud wrench in the spud. Threw a 18" pipe wrench on the spud wrench. slowly cranked it off... didn't take much effort....

    e.) replaced the old union nut and spud with the new one that I got with the 3/4" valve

    f.) reassembled with pipe dope, so that the spud was sticking out about as far out as the old one (old one was 3/8" longer, and it was sticking out ~1 1/8"... new one was 3/8" shorted, and i screwed it in until it was sticking about about 7/8" -> 1")
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