hydralic cylinder gland removal

I have the adjustable spanner wrench pin type gland wrench. It is the black heavy duty type that takes the 3/4" square drive. It is heavy duty but I dont seem to be able to get much torque in it do to it wanting to jump out of pin holes? It dont lock at the hinge I dont think. Very cumbersome to use. Any suggestions? As heavy and thick as the tool is it seems like it will take way more torque than I can apply

hydralic cylinder gland removal