So you're prepared, look up the peening method of loosening cylinder glands. Make sure there's no set screw in the cylinder end holding the gland. Be prepared to weld up a wrench to hold a grip on that gland end to turn it. a ratchet strap or small chain through the ears on the base will hold the wrench in place.
If you have to resort to taking the pin out, use a hydraulic jack and press frame so you're pressing the pin against the opposite ear with the opposite ear supported. Or if there's room, sawzal the pin on both sides of the cylinder, then each side will knock out much easier, and get a new pin.