I used to use (when I was a practicing mechanic) a fairly large cold chisel
that the point had been ground down to a rounded end--forcing it between the
lugs on the cylinders and the head ALWAYS got them separated without removing
the cylinders. You gotta hit em hard and the chisel can't be pointed enough
to hit the cylinder itself but it works.. Beats the alternative. Even if the
clyinder comes a little ways off the block they seem to seal back up ok. I
have also pulled them out far enough to replace the bottom o-ring--just to
the point that the bottom oil ring is about to expose its ugly head...Gotta
be careful but its do-able. Daryl of AA Transaxle