rounded off bleed valve

22 Jan 2006
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United Kingdom
The bleed valve on one of my radiators has become rounded off and now I can't turn it with the radiator key to bleed. I've tried pliers but can't get enough leverage. Any ideas? Will I have to replace the whole radiator?
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if the rad dont have a brass/chrome fitting in it. just a welded in nipple. its not good. i have in the past drilled them out tapped a thread & used a pan head screw with a washer but is tricky & dont always work. If ya gona have to swap rad its not a risk to try with the rad isolated . u need an engieering merchants to bye a drill bit a thread tap & matching screw.
Thanks for the advice Bab, yes its just a nipple, no chrome/brass surround. Just wanted the check that there was no easy solution that I had overlooked, thought there might have been some purpose built tool.
Whilst at the engineering suppliers you could ask about stud extractors.
i If it's in the spare room and you have a sealed system see it as a benefitial extra expansion vessel.
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stud extractor! Great idea, that might just do the job, there are still a couple of flat sides on the nipple so it a 'smaller key' would probably work.
I got around this by tapping a small socket connection into the valve. Did the job.
First get a decent brass key and grind the end pointed so it gets bettter contact

Then try pin-nosed Mole grips, or pliers held together tight with mole grips.

I now use an adjustable spanner which has pointy jaws. It IS a small one, 50mm long overall!

You can also try sawing (or dremel-drill cutting with a disc) a slot across the top and use a screwdriver

One of the above has always worked for me

I've never thought of using a hex socket but just tried a 6mm 12 point one and it fits pretty well. 5.5mm won't fit on a new square.
I had one like that last week, slackened off the rad connections & laid the rad down on the floor. soon bled it through the connections, mind you I was refilling the system so the rad was near as dammit full of air.
Just try several (different makes and types) raditor keys - one of them will grip just enough to get it out.

Once you've got it loose, you could take the whole screw out and get a replacement - possibly from an old rad at the dump !! Could also cut a slot in the grub screw as a temporary measure. i think there's only 2 or 3 sizes of threads used.

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