I used that same Harbor Freight tool to replace the lower ball joints on my 05 Expedition. The joints are pressed in pretty good. I ended up grinding off the top, outer edge of the older joint, then hammered, actually, beat the $#!T out of it to get it out of the lower arm.
When pressing back in, I used an inpact wrench while another person tapped on the center of the C clamp. Kept everything aligned and moving.
PITA from start to finish.
Good luck