do you mean the alloy dust cap so you can inflate the tyre ,if so , you need to gently tap the cap and then try to un screw in the normal way and if it dont undo give it another little few taps ,and then if it still dont undo you can use a small blow lamp a gently warm and tap the cap again untill the cap is removed if the valve is then damaged you will need to have a new valve fitted but this time dont use a alloy dust cap .
mark, April 2008
