Your fears are well-founded because Ford has way more suspension part failures than any other manufacturer, but that is not so common on Rangers. 165 foot pounds seems way too high for such a small bolt. Is that what was specified on the instruction sheet that came with the ball joint? That's about right for an axle nut on a front-wheel-drive car that's twice the diameter.
There's always the concern a ball joint can separate, but for the upper ones, you first have to consider that it is not the "load-carrying" ball joint. It merely holds the spindle upright and the wheel in alignment. All the truck's weight is carried by the lower ball joint. Second, as far as the work you did, the nut would have to come loose on the pinch bolt, (not likely at 165 foot pounds), it would have to walk all the way off the bolt, (not likely once a little rust and dirt get on it), then the bolt would have to slide out, and that's not likely to happen because the ball joint's stud will be pressing on it, THEN you'd have to hit enough bumps to make the upper control arm pull away from the spindle. By the time all that happens you would have noticed the clunking. The stud has a notch for the pinch bolt to go through so it can't come out until the bolt is removed. That's different than the tapered studs used on other applications.
My biggest concern is that pinch bolt snapping from over-tightening, but if that's what was called for, so be it.
Tuesday, November 13th, 2012 AT 10:42 PM