I bought the HF one after using the Autozone free rental one and looked like from the same factory. It looks a bit more rugged than your clamp, but I still saw the body deflecting so much I thought it might crack. Next time, I'll use Rollguy's trick of tightening to build tension, then hammering the end of the screw to encourage the ball joint to slide in, repeat. It also helps to heat the spindle w/ a propane torch to expand the hole. Don't know about your question of the spool seating on the joint, but looks like it still presses on the end so it won't splay out. I used a polyurethane boot (Energy Suspension) instead of the thinner one that came w/ the ball joint. I forgot what brand bj, but probably put in my post (see funola's "redneck removal" thread). It did measure slight larger OD than the original one, which didn't make pressing easier.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans