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vega25

Breaking Bolts!!!! 03 L

9 posts in this topic

I once again have broken a cylinder head bolt. What am I doing wrong? I have set my torque wrench to 36 lbs and things just don't feel right when tighting them down and then snap. First, I don't trust my torque wrench and second...those bolts are expensive. Any tips/tricks.

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I once again have broken a cylinder head bolt. What am I doing wrong? I have set my torque wrench to 36 lbs and things just don't feel right when tighting them down and then snap. First, I don't trust my torque wrench and second...those bolts are expensive. Any tips/tricks.

first off, if it doesnt feel right, it prolly isnt. if you dont trust your wrench, then just do it by feel, you know about what 36 pounds feels like.

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I think your right...I need to become one with the bolt....let the bolt speak to me:-)

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Double-check the torque setting on your wrench. Make sure it's really at 36 ft-lbs. If it shows measurements in inches, did you convert to feet properly?

Practice with your wrench on a bigger bolt that will handle much greater torque. The front and rear axle nuts, for example, take over 60 ft-lbs of torque. Try the wrench set at 36 on one of those. It should 'click' and release way ahead of the bolt being fully tightened. You should be able to still tighten the bolt more with a regular rachet after your wrench 'release' at 36. If not, your wrench isn't working.

Adjust the setting on your wrench down to a very small value, and practice on other bolts to get a feel for how it works. If you can borrow another torque wrench, you can fasten a bolt and use it to compare against your wrench. Do they both require the same force?

This shouldn't apply to a bolt that needs 36 ft-lbs, but I've also developed the habit of not holding the long torque wrench out at the end of the handle on smaller bolts. It's too easy for the long wrench to apply more torque than intended and snap a bolt off without you being able to detect the 'click'. On smaller bolts, hold the wrench down by the ratchet end.

Good luck!

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This comes up atleast once a year.

Most of the time the person is reading the shop maunal wrong. For instance 36 newton meters is only 26 foot pounds. And 36 pound feet is 49 newton meters.

If this is not the case, then my appologies, but it is pretty hard to break one of these bolts.

It is hard for a torque wrench to be that far out, unless it has been seriously abused. Most of the time they read higher (spring relaxes) than actual.

MGS

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I once again have broken a cylinder head bolt. What am I doing wrong? I have set my torque wrench to 36 lbs and things just don't feel right when tighting them down and then snap. First, I don't trust my torque wrench and second...those bolts are expensive. Any tips/tricks.

Buy a manual.

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Sounds great...the manual shows one how to read the values.. N-m(kg-m, ft-lb). The first one was a cylinder bolt. This one was a cylinder head bolt. After further investigation into the $8.80 bolt. I mistakenly had it set for 36 lbs rather than the change in value from the cylinder to the cylinder head bolts of 26 lbs....so there you have it....pilot error. A series of small mistakes led to the fatel crash. I should have double checked.

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On my XR600, the cylinder bolts are 36, and the head is only 26. Don't know if they are the same, but make sure you are using the right one.

I felt my torque wrench was off. I went out and got one of the bending beam and pointer types for $15. No springs or settings to get out of whack on one of those. I calibrated my clicker using it, and my it was way off on the low side (30%).

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One other thing is that it is very likely (I don't have a XRL or XRL manual) that the head bolt threads/washers/nuts should be oiled with engine oil prior to torquing. 400EX manual specifies this and being the same engine design I imagine the XRL manual says the same. :thumbsup:

Sounds like you discovered your mistake but I thought I'd throw that out there.

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