Stuck Bleed Nipple on Rads

[hondo]

Hi folks I’d be grateful for any ideas / help
In my central heating system I have round top double panel radiators, the bleed screws are not fitted at the ends, but are fitted below flush on the inside of the radiator panels, around 40mm in from the ends.

Over the years, a number of these bleed nipples square heads have worn, and therefore will no longer turn, using a radiator key. This wasn’t a problem in the past but it's become one now, the radiators need bleeding.

Has anyone found a way of removing and replacing bleed nipples situated in such a daft place like this?
BTW there are two nipples per radiator, one on each side of the double panels
Picture in link http://img.photobucket.com/albums/v401/ ... Nipple.jpg

Any help much appreciated

Thanks hondo

[tom squires]

hi
usually the best bet is to go down to a local merchant and see what size bleed valves are available
and treat it as trial and error until you get the right size one
if you cant unscrew the nipple then the only other option is to replace the radiator
not great for the wallet but its the only other option