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The nuts at the knuckle on my outer tie rod ends are castle nuts, which are locked by cotter pins fed through holes in the studs. The nuts also have a torque spec (27.0±2.5 N∙m, in this case).

If I tighten them down to the midpoint of that spec, the holes and the crenellations may or may not align such that I can get the pin through. It's possible to rotate the stud, since its base is a ball joint, but that requires removing the nut completely so that the stud can be popped out of the knuckle again. That's likely to require repeated attempts and be an utter pain.

Is the correct procedure here to deliberately use the range in the torque spec to allow the hole to line up? That is, should I torque the nut down, then -- staying within ±n -- turn the nut in or out to access the nearest slot to the hole?

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+1 for "crenellations" – mac May 1 '13 at 15:00
up vote 6 down vote accepted

I would not back the nut off to align the nut with the cotter pinhole. Doing so can result in the taper between the knuckle and the tierod becoming loose. The cotter pin would keep the nut from backing off but it would not prevent the tapered shaft of the tierod from spinning in the tapered hole of the knuckle. As @MikeSaull has suggested lube the threads. I would torque it to spec, then if necessary tighten enough to align the castle nut and cotterpin hole.

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Interesting perspective. I'd always assumed backing-off was the right way to do it, but what you're saying makes sense. – R.. Apr 30 '13 at 22:34
You may be thinking of adjusting tapered wheel bearings, if that is the case backing it off is the correct technique. – mikes Apr 30 '13 at 22:43
That's an excellent point about not allowing the stud to be loose in the knuckle. I think this is my answer. I've found, however, that with the hole pointed in the direction I'd like it to be (for ease of future removal), I'm having to go nearly twice the recommended torque to get it to line up. It looks like I will need to combine rotating the stud with a more slight over-torque. – Josh Caswell May 1 '13 at 17:59

I would use some anti-seize on the threads then tighten it to torque spec. If it doesn't line up then I would tighten it until it does.

This is just what I would do. If it is a weak bolt or a really bad place for the threads to strip then I would just loosen it until it lines up. Once the cotter pin is in it shouldn't go anywhere anyways.

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I was hoping for some general advice about this arrangement, should I encounter it somewhere else, so your mention of weak bolts or stripping is appreciated. – Josh Caswell May 1 '13 at 18:00

I just stumbled across this entry in my factory manual, which says that overtightening is the correct procedure.

The safe margin is given by rotation rather than torque, however -- up to 60˚ past the point where the specified torque is reached.

enter image description here

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Always tighten to align with cotter pin hole on tapered fittings and most anything else that DOESN'T INVOLVE THE LOAD ON A BEARING. I've written and edited dozens of factory tech manuals and technician training programs for auto manufacturers. Doesn't make me an expert but I write like one. ;<)

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