That"s about it, unbolt the cylinder, lift it off the piston will be inside. The piston and rod are not connected, rod just rests in the piston socket. Blow the piston out with puff of air at the hyd fitting.
O-rings are not huge, just around 4" as I remember it. Any hydraulic shop can fix you up for less than a saw buck.
I can look up the current Case p/n if you want to go that route. Case still had them available a couple of years ago, no different than what you can buy elsewhere.