Regulator lubrication

I have always had problems with the regulator passing when it is closed.  Just opened up the steam chest and the inside is very dry and rusty, with scoring on the regulator puck face.  I know that the later Fodens had a stainless insert but I was wondering if ther is any way of getting lubrication into the steam schest.  The lubricators are working well with plenty oil going into the valve gear.  Would fitting a displacement lubricator to the valve chest cover be a solution?  Anybody else had similar problems and solutions??
Cheers
Tom