<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


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 
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.

Jay Maechtlen
'61 2-dr modified w/fiberglass skin,
transverse 3.8 Buick V6 TH440T4 trans
Now with 3800 series II supercharged!

More information about the VirtualVairs mailing list