Originally Posted by speedjester
Try using a large pipe wrench.. (With a piece of rubber for padding so not to mar the cylinder) to hold the cylinder while you go at it with the impact gun..
Not sure I'd use a pipe wrench on a polished Hyd cylinder but anyway if its that difficult to get loose after you've done three, something may be seriously wrong. It's not difficult to remove the ram. Disconnect the two hydraulic lines with bucket to drain the tubing. Remove a max 8 maybe 3/4 inch bolts and take the entire assembly to a machine shop. Chances are the bolt is thread damaged from the load and you won't get it out w/o major damage.
A shop can get it out, chase the thread and reassemble for you. Just my thinking, if you strip it, you'll probably go to shop anyway or buy new.