Steering TRE bolt failure

[emkeiz]

Guess this is more steering related than suspension related, but I was putting new struts on my truck while it happened so I figured I'd post it here. Was working on torqueing each bolt to specs. On the driver's side, the bolt that connects the steering tie rod end to the steering knuckle pulled in half (before reaching the spec). Thought it was odd, has anyone else had something similar happen?

Luckily its fairly easy to replace, so no big deal. Just a bit concerned with how easily it failed

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[ParkerAzJeff]

What were you trying to torque it to?

 

[P. A. Schilke]

Guess this is more steering related than suspension related, but I was putting new struts on my truck while it happened so I figured I'd post it here. Was working on torqueing each bolt to specs. On the driver's side, the bolt that connects the steering tie rod end to the steering knuckle pulled in half (before reaching the spec). Thought it was odd, has anyone else had something similar happen?

Luckily its fairly easy to replace, so no big deal. Just a bit concerned with how easily it failed

Hi Emma,

This is a classic cap and cone tensile failure . Has your torque wrench been checked to calibration. If in spec, I would suspect it was over torques prior to your retorquing. Unusual failure. Now the interesting part. Being a taper fit, once seated a taper joint is usually robust enough that the nut is not even needed. Weird failure...

Here is a back story I told before on the E450 tie rod

https://www.ranger5g.com/forum/threads/carid-bait-n-switch-scam.7838/page-2#post-140334

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[jss81258]

Hard to tell from the photo, but it looks like it started as an existing defect. Note the dark area between 3 and 4 o'clock. It appears that the defect rapidly cracked about half way across, then tore the rest of the way.

I'd guess that the stud either had a manufacturing defect, or was a bit over torqued initially and cracked a little. The dark spot indicates it's been there a while. And, threads are stress risers.

I always find it interesting when studs break off up in the nut. My understanding is this is where the greatest stress is, but it makes better sense to me that the stud should break off flush with the nut.

I don't think I've ever seen one break like that, though. I have seen the other end of the tie rod break, but when the wheel has taken a hard hit, like in a wreck.

 

[emkeiz]

Hi Emma,

This is a classic cap and cone tensile failure . Has your torque wrench been checked to calibration. If in spec, I would suspect it was over torques prior to your retorquing. Unusual failure. Now the interesting part. Being a taper fit, once seated a taper joint is usually robust enough that the nut is not even needed. Weird failure...

Here is a back story I told before on the E450 tie rod

https://www.ranger5g.com/forum/threads/carid-bait-n-switch-scam.7838/page-2#post-140334

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

Hard to tell from the photo, but it looks like it started as an existing defect. Note the dark area between 3 and 4 o'clock. It appears that the defect rapidly cracked about half way across, then tore the rest of the way.

I'd guess that the stud either had a manufacturing defect, or was a bit over torqued initially and cracked a little. The dark spot indicates it's been there a while. And, threads are stress risers.

I always find it interesting when studs break off up in the nut. My understanding is this is where the greatest stress is, but it makes better sense to me that the stud should break off flush with the nut.

I don't think I've ever seen one break like that, though. I have seen the other end of the tie rod break, but when the wheel has taken a hard hit, like in a wreck.

What were you trying to torque it to?

Thanks for the replies! Upon further inspection I noticed that I read the spec for an adjacent bolt, which was way over the spec for that one.... Aagh. So this ones on me.

Still an interesting failure, I have always been fascinated with tensile failure. Hopefully this will remind me to stop working when I'm too tired to read right, lol.

Cheers

 

[P. A. Schilke]

Thanks for the replies! Upon further inspection I noticed that I read the spec for an adjacent bolt, which was way over the spec for that one.... Aagh. So this ones on me.

Still an interesting failure, I have always been fascinated with tensile failure. Hopefully this will remind me to stop working when I'm too tired to read right, lol.

Cheers

Hi Emma,

At least we all know and more importantly you know to prevent another occurrence! Thanks for your honesty! Refreshing!

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[P. A. Schilke]

Hi Emma,

You do not have to align the vehicle again if only replacing the tie rod. Just count the threads up to the jamb nut and then ensure the same threads are exposed with the new tie rod... In your case where I think you have lifted the truck, then an afterwards alignment is necessary...

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[emkeiz]

Hi Emma,

You do not have to align the vehicle again if only replacing the tie rod. Just count the threads up to the jamb nut and then ensure the same threads are exposed with the new tie rod... In your case where I think you have lifted the truck, then an afterwards alignment is necessary...

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

Hey Phil,

I left a paint mark where the original tie rod sat so I could easily get the new one in the original spot. You are right though, I lifted it and have an alignment scheduled.

Thanks again!

Emma

 

[emkeiz]

^ im going to go out on a limb here and say the OP does NOT have a tailgate damper....or at least hasnt had one long enough for muscles to shrink and disappear ?

Hahaha. Your first assumption is correct!

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