<VV> Fuel Leak / lug nuts
Jay Maechtlen
jaysplace at laserpubs.com
Mon Oct 1 00:16:57 EDT 2018
On 9/28/2018 7:42 PM, Joel McGregor via VirtualVairs wrote:
> My truck calls for 450-500 ft lbs of torque. My arms aren't calibrated for that so I carry a torque wrench on my truck. It takes pretty much all my weight on a 5' to get them there. As I'm typing that I realized that is way off. A 5' bar should get them close to 1000 ft-lbs. I guess my digital wrench is way off. I hope I'm not ruining my studs. No problems so far. I set it at 450 with anti-seize.
> Joel McGregor
>
>
> _______________________________________________
A couple of discussions on an engineering forum, fwiw
https://www.eng-tips.com/viewthread.cfm?qid=57211
https://www.eng-tips.com/viewthread.cfm?qid=434861
https://www.eng-tips.com/viewthread.cfm?qid=375511
https://www.eng-tips.com/viewthread.cfm?qid=405447
Personally, the only vehicle I remember having lug trouble with was our
89 Aerostar, where I saw galling on the tapered facess of the lugs and
corresponding seats of the wheels.
I also saw wear on the lug threads and corresponding threads of the lug
nuts.
I replaced the lug nuts, cleaned everything up, and used anti-seize on
threads and seats.
Obviously I worked around the bolt circle a couple of times while
snugging things down with my cross-bar lug wrench.
I had the wheels off and on a few times after that (brakes and such) and
the lugs were holding up o.
A couple of comments on stretch -
Yes, steel is elastic. Yes, when you torque a lug nut, you are
"stretching" the lug.
Normally, that is elastic deformation - when you loosen the lug nut, the
lug returns to its previous shape and length.
Plastic deformation is where something takes a set, and is not the same
dimension as it was before being deformed.
Generally, even if you stress/elongate steel to where it undergoes
plastic deformation, it still holds the tension equal to its strength at
the point it started stretching.
- consider the fact that lots of engines use bolts that are one-use,
torque-to-yield fasteners.
Ah, that's the term - "yield" is when a material has permanently changed
dimension - it has stretched (or possibly crushed) and changed shape.
Anyway, the discussions in previous emails illustrate that wheel
fastening isn't a simple topic.
Re the links to eng-tips - there are lots of other forums there, many
have discussions that technically inclined gearheads may enjoy.
Cheers
Jay
--
Jay Maechtlen
SoCal
'61 2-dr modified w/fiberglass skin,
transverse 3.8 Buick V6 TH440T4 trans
Now with 3800 series II supercharged!
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