You need dedicated tools or you need to exert upward force on the knuckle and downward force onto the lca.

You can exert upward force to the knuckle by propping it up with a Jack.
Once a substantial amount of force is applied, swear at it and threaten to burn it if it doesn't come off. Then you hit it as hard as you can with the biggest hammer you can find. (Bigger = more force)

If all else fails. Cbauto does home visits.