Upper A Arm Pivot Shaft End Bolt Slip

[buckman]

Hello, working on FFR MK4 today and installing the upper control arms. When tightening the nuts on the ends of the pivot shaft there was a loud crack and the bolt coming out of the end of the pivot shaft slipped. I tried the other side and the same result. I can't seem to be able to tighten those nuts appropriately without the bolt slipping. So I am stuck, seems like the bolt coming out of the shaft has slipped on the inside of the bracket and therefor failed.

Thanks for any help.

Best,
Jeff

[facultyofmusic]

I have an idea about what you're talking about, but a few pictures would be super helpful. It sounds like an incorrectly sized nut?

[buckman]

I have an idea about what you're talking about, but a few pictures would be super helpful. It sounds like an incorrectly sized nut?

Thank you for your help. The nut is unusually hard to tighten but it is the nut that came with the a arm already started and the same on both ends and both a arms. The a arms come loosely assembled.

Trying to figure out how to attach a photo. 161432161433161432161433

[edwardb]

Those are distorted thread lock nuts and normal for them to be hard to turn when the threaded portion of the cross shaft starts to exit the other side. Especially the first time they're used. Are you positive the inner threads are turning? A little anti-seize on the threads doesn't hurt. The UCA's are from Specialty Products Company (SPC). The cross shaft is one piece with threaded ends. Anything's possible. But hard to imagine something broke. Haven't heard of that before during assembly.

[buckman]

Those are distorted thread lock nuts and normal for them to be hard to turn when the threaded portion of the cross shaft starts to exit the other side. Especially the first time they're used. Are you positive the inner threads are turning? A little anti-seize on the threads doesn't hurt. The UCA's are from Specialty Products Company (SPC). The cross shaft is one piece with threaded ends. Anything's possible. But hard to imagine something broke. Haven't heard of that before during assembly.

Thank you. I am pretty sure something is seriously wrong inside because it is making an awful crack and slipping when tightening. I haven’t been able to get any of the nuts tight on that pivot shaft. If it is a solid member then it has sheared off on the inside which would be very strange, didn’t think I had that strength, not sure what to do.

It makes me think I’m doing something wrong that both sides failed in the same way.

[egchewy79]

sounds like something has sheared off to me. I've had the same thing happen with a timing cover bolt and also head bolt. you're trying to tighten to proper torque, then "SNAP" and you lose all tension. I can't recall having any trouble with the upper control arms.

[buckman]

sounds like something has sheared off to me. I've had the same thing happen with a timing cover bolt and also head bolt. you're trying to tighten to proper torque, then "SNAP" and you lose all tension. I can't recall having any trouble with the upper control arms.

Ok, I found if I just move it slightly instead of longer pulls that I can get it tightened. So I now have all four where they should be. I’m a little worried about that part failing later when driving, I guess I’ll have to see about that.

Thank you again for your help.

[edwardb]

Thank you. I am pretty sure something is seriously wrong inside because it is making an awful crack and slipping when tightening. I haven’t been able to get any of the nuts tight on that pivot shaft. If it is a solid member then it has sheared off on the inside which would be very strange, didn’t think I had that strength, not sure what to do.

It makes me think I’m doing something wrong that both sides failed in the same way.

Your pictures appear to be the same SPC parts that I've used several times. They're supposedly chromoly which, unless defective (obviously...), shouldn't break with normal hand tools. They play a major role in the carrying the front suspension. If they did break, I would expect would be external, not internal, since they are one piece. So should be loose if you remove one or both of the pivot bolts. Nuts, when seizing up, can make awful creaking sounds. Although that's more common with SS parts than these. (Ask me how I know.) I still question whether something actually broke. But don't know what else to say.

https://hosting.photobucket.com/images/ab234/edwardb123/New_Bitmap_image.bmp?width=960&height=720&fit=bounds (https://app.photobucket.com/u/edwardb123/a/186cc666-68d0-4881-b53c-af005ffe3552/p/cb19aef5-3922-4c5f-bf46-743d435ec6db)

[johnnybgoode]

As Edward has indicated the cross shafts are supposed to be solid steel so hard to think they would fail on tightening but you never know. Given where you are in your build and the importance of those components I would disassemble the cross shafts and inspect them. At the same time, you could add some anti-seize to hopefully make them easier to turn/reassemble. Those nuts should just be lightly touching the Delrin bushings and the UCA should move up and down with slight to medium drag after it's been fully greased. If the arms are binding or not moving freely you need to disassemble and correct whatever the problem is. Also when you make camber/caster adjustments with the 4" hex adjusters make sure the pinch bolts are loose as this can cause the assembly to bind up if they are left tight when the alignment adjustments are made. Good luck. Scott