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Snapped Upper control arm bolt


msavides
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I noticed the other day that my pathfinder is wondering all over the road. I also noticed a clunk when backing out of a parking space.

 

This morning I decided to jack it up and take a look. I was shocked to find my wheel at a weird angle, when I jacked it up the wheel went straight again. I grabbed the wheel and pulled and then I saw my upper control arm separate from the frame to reveal a snapped off bolt.

 

 

So I take the wheel off and get to drilling out that bolt. The bolt had not loosened before it had snapped, it was tight when it snapped.

 

I had previously replaced them with longer bolts.

 

After drilling a hole all the way through the bolt I had to go get some bolt extractor to remove it. It came out without much fuss

 

The replacement bolts where 10.8 bolts. Now I am worried that they are not strong enough and need some advice on what grade bolts I should be using there.

 

So for now I have put in 2 new 10.8 bolts and am wondering if it was just a fluke or do I need to replace them with stronger bolts

 

 

Thanks in advance for any advice.

 

Mark

Edited by msavides
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With metric bolt grades, there is 8.8, 10.9, 12.9. Harder is not always better, depending on application, but in this case I have to ask what you had installed; 8.8 or 10.9?

I know you wheel hard, so could you have snapped a bolt that was too hard to yield?

 

B

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my bolts are 10.9 bolts.( don't know where I got 10.8 from) the longer ones were put in, just to get more threads in the frame. I did not put any more shims in. I have not had it re aligned since i put the bolts in years ago. They had been in for about 8 years

 

I did not wheel it very hard around the time when the bolt snapped, I don't think it is possible for the bolt to have snapped without knowing it as it would throw my alignment way off.

 

I am going to have to get it realigned now anyways since I am not sure If I lost any shims when the bolt snapped

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SO.

 

since the 10.9 bolt snapped. should I go with 8.8 so it does not snap but instead bends, Or should I go with 12.9 where it is harder but will still snap at failure.

 

Anyone have any experiences with different hardness of bolts in different situations.

 

I know in this application it is shear load as well so I am not sure where this falls.

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Honestly I would throw another set of 10.9 in there and run it. 10.9 metric is equivalent to grade 8 standard, and many people have run them without issue. Me included. I do know that some bolt suppliers had "counterfit" bolts that were not as strong as they claimed. There was a store here selling them at one time.

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SO.

 

since the 10.9 bolt snapped. should I go with 8.8 so it does not snap but instead bends, Or should I go with 12.9 where it is harder but will still snap at failure.

 

Anyone have any experiences with different hardness of bolts in different situations.

 

I know in this application it is shear load as well so I am not sure where this falls.

This makes me wonder what the stock bolts are...

 

B

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  • 2 months later...

I have never replace my bolts.. but one of mine snapped a long time ago and I took it into a shop (before i started working on it on my own) and they welded a bolt in there somehow. I took it in to get aligned last year and they said they couldn't because there was no way they could get shims in the upper control arm where that bolt was welded. (apparently they just welded the whole thing so there's no adjustment anymore) My alignment is terrible now because of that and I want to fix it and somehow get that welded bolt out of there.

 

Any recommendations??

 

When you put new bolts in what did you do?? Did you drill the old one out of the frame and then thread it with a tap?? Or do you go through the frame and put a nut on one side?

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SO.

 

since the 10.9 bolt snapped. should I go with 8.8 so it does not snap but instead bends, Or should I go with 12.9 where it is harder but will still snap at failure.

 

Anyone have any experiences with different hardness of bolts in different situations.

 

I know in this application it is shear load as well so I am not sure where this falls.

It is my belief that anything higher than 10.9 in tension application will cause the frame nut to strip instead of the bolt. I would rather replace a bolt than put (another) time-sert in my frame...

 

This makes me wonder what the stock bolts are...

 

B

I don't recall if the OE bolt heads had any markings (unmarked, 7(7T), 9(9T), raised lines, etc...) But this chart might shed some light... mind, not all unmarked bolts are low grade.

strengths.gif

Edited by MY1PATH
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BTW never had 10.9 or stock bolt snap on me and I used to jump my pathfinder lol. I think it was a fluke. What torque are you using?
Stock is 80-108 ft-lb.

Edited by MY1PATH
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I have never replace my bolts.. but one of mine snapped a long time ago and I took it into a shop (before i started working on it on my own) and they welded a bolt in there somehow. I took it in to get aligned last year and they said they couldn't because there was no way they could get shims in the upper control arm where that bolt was welded. (apparently they just welded the whole thing so there's no adjustment anymore) My alignment is terrible now because of that and I want to fix it and somehow get that welded bolt out of there.

 

Any recommendations??

 

When you put new bolts in what did you do?? Did you drill the old one out of the frame and then thread it with a tap?? Or do you go through the frame and put a nut on one side?

 

 

I drilled the broken bolt and used a bolt extractor and unthreaded the broken bolt, I replaced it with another 10.9 bolt.

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BTW never had 10.9 or stock bolt snap on me and I used to jump my pathfinder lol. I think it was a fluke. What torque are you using?

Stock is 80-108 ft-lb.

 

 

 

I torqued to 110 ft lbs. but To be honest I am not sure what the last alignment guy torqued it to.

 

I choked it up to a defective bolt. I don't jump my pathfinder so I have no idea why it broke.

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I have never replace my bolts.. but one of mine snapped a long time ago and I took it into a shop (before i started working on it on my own) and they welded a bolt in there somehow. I took it in to get aligned last year and they said they couldn't because there was no way they could get shims in the upper control arm where that bolt was welded. (apparently they just welded the whole thing so there's no adjustment anymore) My alignment is terrible now because of that and I want to fix it and somehow get that welded bolt out of there.

 

Any recommendations??

 

When you put new bolts in what did you do?? Did you drill the old one out of the frame and then thread it with a tap?? Or do you go through the frame and put a nut on one side?

Take a pic and post it. What fark tard shop did you use?

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I torqued to 110 ft lbs. but To be honest I am not sure what the last alignment guy torqued it to.

 

I choked it up to a defective bolt. I don't jump my pathfinder so I have no idea why it broke.

That's too much, I only torque mine to 90 ft lbs. Because I have a fear of stripping the frame holes. Never had an issue even with longer (60mm instead of 50) bolts so I can add enough shims to get the camber out of ricer stance.

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