the only thing I have had work is to take a open end combination wrench--think i used 12mm. and use it as a fulcrum lever on the ears of the cylinder against the head. i tried for days to get my sleeves free til someone from this list recommended this method. took me about 10 minutes to get both heads off. worked slicker than snot. obviously--careful not to mar the head. combination wrenchs has quite a nice progressive  lobe to em--almost exactly what they were designed for it seems

mike