1969 Chevy C10 Stepside upper ball joint

[REDROCKER652002]

OK Guys, I feel like a fool because this should not be a difficult thing. My son, 18 yo, took his truck to get the front end aligned. Dude at the shop said the upper ball joints were bad and needed replacement. So, he decided he wanted to do it himself. Not a bad thing by any stretch. He goes, gets a pickle fork, gets the ball joints from a parts house local. He gets the old one off, no real issue. When he puts the new ball joint in, the castle nut will not screw down far enough to get the cotter key in the hole. He gets a box wrench and puts as much pressure as he can and the nut won't go any farther. So, my question is two fold. Number 1, the rubber boot, does it separate and go under the control arm? And my second question, do I need a impact wrench and socket to somewhat press the knuckle back onto the shaft of the ball joint? My thinking is that the darn thing needed to be pounded off, so maybe it needs a bit more torque to get back on than my son can provide himself.

And, I have searched this and I have not seen the answer, but maybe i am just a bit lame. LOL.

Anyway, I am going to try and let him figure it out, but if I can get some input I would appreciate it.

Thanks

RR