The doorlock on the drivers door of my wife's 1999 Ka 2 has become stiff to open i.e. when the key is turned anti clockwise to actuate the autolocking mechanism to unlock the vehicle there is resistance although the actual mechanism works fine if this is overcome. There is no similar resistance when turning the key clockwise to relock. Before reaching for the WD40 I recall that this may not always be the correct approach. Comments please?