name of this part?

If you are currently removing these parts from the car, then the pitman arm puller would be the tool to remove that arm that comes off your steering box and connects to the centerlink. (all the parts pictured are the parts that connect from that centerlink to your hubs which the wheels brakes are attached to.
They have a tool called a ball joint spreader, or separator.
If you don't care about the parts that are coming off, then remove the cotter pins, take the nuts off and smack the end of the threaded part sharply and it's out.