You can remove the pistons with a grease gun and do no damage to the cylinder pistons or spring. Any time I've ever beat on cylinders with a hammer nothing good ever come of it. If this is a old huck system they can be redone for about $3 a piece. Just clean the pistons and hone the cylinder clean. It's best to hone the cylinders in a drill press that you can get down to around 100 rpm most hand drills turn way to fast and leave a bad finish I've had very good luck with going as much as 7 or 8 thou over as long as it is honed to a fine finish. I'll put a properly redone oe cylinder against the whang chang imports any day. The last set of cylinders I did for a 52 chevy set me back about $6 and a nice quiet afternoon in the shop, still working great after 2 years. If you have trouble getting the bleeders lose I've got a fix for that to.
