DEPRIEST, 'no prob. with my master ("ignition" switch) - it was replaced several months ago when it began to "give trouble". I'm replacing door handles in next couple of days because of loss of chrome on exterioir; I'll have the tumbler assemlies out during the replacement; 'just want to clean & lube them properly. Also want to keep the master switch properly lubed. I have been lucky enough so far to have had master switches replaced on 3 MB's before they got to the drill & hack saw stage. Therefore, it's improtant to keep them properly lubed. Meanwhile, I'm using spray silicone; anything better? Maybe, graphite? Thanks for replies.