Torque for Nuts and Bolts

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boatbuilder
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Torque for Nuts and Bolts

Post by boatbuilder »

So I'm putting my suspension and brakes back together, following the torque settings in the Bentley.
Managed to strip the threads off one of the new M10 bolts on the lower ball joint support - I'm guessing it makes a difference that I had copper grease on the bolt.
So what do people do when reassembling? I'm using Nyloc nuts on most new bolts - should I install them dry or with a bit of lube and what torque settings should I use?
I'm tempted to abandon the torque wrench and just tighten stuff by "feel" as you can't really properly feel the tightness as well using the torque wrench due to the big leverage you have...
I'm using one of these fellas....

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Bubble Meister
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Re: Torque for Nuts and Bolts

Post by Bubble Meister »

The suspension, steering and brakes are safety critical. I'd be using a torque wrench every time. Maybe you have mixed up lb.ft with lb.in? Or maybe a poor quality bolt? I don't remember copper grease being specified in Bentley or Haynes.
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itchyfeet
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Re: Torque for Nuts and Bolts

Post by itchyfeet »

adding grease ups the rotation and stress in the bolt before a torque level is reached thats why you should not lube critical bolts such as wheel bolts.
Nylocs may also affect correct torque so shouln't be used on safety critical parts unless manufacturer states, the torque is set to stop them coming loose, you don't need nylocks.
Don't use stainless either where the origional bolt was high tensile, i.e marked 8.8 and above
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Re: Torque for Nuts and Bolts

Post by boatbuilder »

itchyfeet wrote:adding grease ups the rotation and stress in the bolt before a torque level is reached thats why you should not lube critical bolts such as wheel bolts.
Nylocs may also affect correct torque so shouln't be used on safety critical parts unless manufacturer states, the torque is set to stop them coming loose, you don't need nylocks.
Don't use stainless either where the origional bolt was high tensile, i.e marked 8.8 and above

I supposed I could copper grease the shaft of the bolt and clean the grease off the threads with brake cleaner before tightening...
I'm using 8.8 bolts as I can't find 10.9 around here anymore so thats probably not helping as well.
I read somewhere that to get the correct torque, you test the nylock nut to see how much "drag" it causes and then add that to your specified torque value.
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itchyfeet
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Re: Torque for Nuts and Bolts

Post by itchyfeet »

if your origional bolts were 10.9 you MUST replace with 10.9, thats probably more the reason you snapped them.

Come this is important you could kill somebody messing around changing the spec of brakes and suspension without knowing what you are doing.
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Re: Torque for Nuts and Bolts

Post by boatbuilder »

Please accept my sincere apologies. *goes away with tail between legs*
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Re: Torque for Nuts and Bolts

Post by CovKid »

Used to use a torque wrench in the early years but soon discovered that this equated to tight as possible by hand then a clout with the club hammer on the end of the wrench to bite home. Its light pressures like rocker nuts and cylinder heads that need more accuracy lest you strip them but even those I found a technique that matched torque settings. Practice and experience in the end but definately wise to use a torque wrench if you're unfamiliar with the pressures involved.
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Re: Torque for Nuts and Bolts

Post by kevtherev »

For me any tightening into aluminium I would use a click torque wrench.
Anything steel it's just tight and then a grunt.
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Re: Torque for Nuts and Bolts

Post by CovKid »

Thats the one :D
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itchyfeet
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Re: Torque for Nuts and Bolts

Post by itchyfeet »

I bet you can tell your tyre pressures by kicking the tyre too :lol:
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Re: Torque for Nuts and Bolts

Post by CovKid »

No but I can tell how much water is in the washer bottle by rocking the camper. :rofl

Kev can tell you the voltage in the battery by divine thought. :D
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Re: Torque for Nuts and Bolts

Post by ghost123uk »

CovKid wrote:Practice and experience in the end but definately wise to use a torque wrench if you're unfamiliar with the pressures involved.
Agreed, without lots of previous experience as to the "feel" of various torque settings and different metals / applications, the use of a click torque wrench is recommended. Also +1 on the "don't use anything other than the recommended bolt / nut types on brakes and suspension".

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Re: Torque for Nuts and Bolts

Post by CovKid »

You're too quick John. Always struggled with that one. :D
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Re: Torque for Nuts and Bolts

Post by Bubble Meister »

Based on the advice on here I'll bin the torque wrenches at work, instead I'll just hammer the ratchet. Torque settings are completely over rated in the aviation industry!
Introducing Bubble, the B reg '85, 1.9 DF WBX (currently with a DG fitted!)

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Re: Torque for Nuts and Bolts

Post by Titus A Duxass »

Bubble Meister wrote:Based on the advice on here I'll bin the torque wrenches at work, instead I'll just hammer the ratchet. Torque settings are completely over rated in the aviation industry!

Torque pfft. Completely overated! :rofl
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