I agree with John, new one needed, but some times they do not want to come out of the cylinder, and you can end up damaging the cylinder then you need a new one aswell. I hate changing them for this reason. Sorry to be a permist , just letting you know what could happen, then again it could come out now problem, cost if it come out approx £60/80, if not £100,s good luck
erj, October 2009