<VV> Fuel Leak / lug nuts

Hugo Miller Hugo at aruncoaches.co.uk
Fri Sep 28 12:48:44 EDT 2018


And of course some people think that if they do the nuts up tight enough 
they won't come off. They then stretch the stud beyond its elastic limit as 
you lose most of the 'spring' force that keeps it all together. That's if 
they haven't stretched the threads first.
I have never used a torque wrench on wheel nuts on my buses - I do them up 
by feel - they don't need to be too tight if all faces are clean and the 
threads are not stiff. I never check them, and I've never had a problem 
ever. The plus side of using lube on the threads is that you can get them 
apart again.
Another sort of related comment - I notice that coarse (UNC) threads are 
widely used on American vehicles. In the UK we used to use BSF (British 
Standard Fine) and Whitworth (which co-incidentally has the same pitch as 
UNC). Then we went over to UNF threads, with UNC only being used on the 
bottom of studs or in aluminium. Now of course everything is metric, which I 
hate. It is an artificial system imposed by Napoleon on the countries he 
conquered - every measurement is supposed to be a tiny fraction of the 
circumference (or maybe diameter?) of the Earth. (Of course, if it is a 
fraction of the circumference, it cannot also be a fraction of the 
diameter!). Traditional measurements, on the other hand, are based on the 
human body. The decimal system is divisible only by 2 and 5, whereas the 
traditional 'duodecimal' system divides by 2,3,4 and 6.  Plus the fact that 
centimetres are not included in the S.I. metric system, so you get 
measurements given in hundreds of millimetres. If I told you I was 5' 10" 
tall, you would know immediately what that looked like. If I told you I was 
1.778 metres you wouldn't have a clue.
Ok, rant over ;)


-----Original Message----- 
From: Joel McGregor via VirtualVairs
Sent: Friday, September 28, 2018 11:27 AM
To: virtualvairs at corvair.org
Subject: Re:  Fuel Leak

Yes.  The square end is the lug nut for the inner wheel.  The outer wheel 
nut screws on to the inner lug nut.
I'll bet the right rears come loose also but they don't fly off because the 
nuts don't unscrew themselves completely from being loose.
Once the left gets loose the nuts spin off and there goes the wheel.
I forgot to mention that I believe the hub center lug nuts have the torque 
stamped into the nut here.

Joel McGregor



-------- Original message --------
From: Hugo Miller <Hugo at aruncoaches.co.uk>
Date: 9/28/18 5:16 AM (GMT-06:00)
To: Joel McGregor <joel at joelsplace.com>
Subject: Re: <VV> Fuel Leak

Budd wheels are the ones with the square end on the stud, aren't they? That
system doesn't exist in the UK - we always used to have both wheels located
by one set of lug nuts. The nuts were conical, and they had conical collars
on the inside of the inner wheel, plus of course left-hand threads on the
left of the vehicle. That system worked perfectly well, and there was no
such thing as 'wheel-loss syndrome' in those days.
Incidentally, I have a 1980 Kenworth Cabover that has larger diameter studs
& nuts, but the nuts are shallower. It's for sale if anybody's interested.
Detroit V8 2-stroke / 13 spd.
You are probably the first person I have had agree with me about lubricating
the threads. Everybody here seems to think it will make them fall off, but I
have ben doing this for a very long time & I never even need to check the
lug nuts. I also have 'ric-clips' fitted. These are like a figure-of-eight
spring clip that goes over two adjacent nuts, and makes them stiff enough to
turn that they are never going to fall off. The US equivalent is 'Zafety
lugs' or whatever they're called - a neat little plastic clip that does the
same job.
One area where I am going to disagree with you is where you say that the
problem isn't down to thread rotation. The ONLY wheels that ever fall off
since we switched to right-hand threads are the left-hand rears. Right-hand
rear wheels stay put, as do the fronts as they have less work to do.
Salt is a major problem on UK roads, especially if, like me, you have one
steel wheel and one Alcoa wheel on the back! That is why I religiously scurf
all mating surfaces then lubricate them, preferably with something like
cavity wax to keep the corrosion at bay.



-----Original Message-----
From: Joel McGregor via VirtualVairs
Sent: Friday, September 28, 2018 9:31 AM
To: virtualvairs at corvair.org
Subject: Re:  Fuel Leak

Since I recently bought a large truck I've done a lot of reading on this.
Hugo is mostly right except wheel loss is an issue in the US also since
trucks switched to all RH threads.   BUT the thread switch wasn't the
problem.  The system with RH and LH threads on large trucks with dual wheels
is commonly called Budd or lug center.  They have tapered seats that center
the wheel and the hub center system has all RH threads BUT this still isn't
the issue.  The problem was created because the old Budd system clamped each
wheel sepearately and the new system clamps both wheels at the same time.
As Hugo mentioned this creates a whole stack of surfaces clamped together in
the new system.  Hub to drum, drum to inner wheel, inner wheel to outer
wheel and outer wheel to lug nut washer.  (No tapered seats on hub center
systems)  Any paint, dirt, rust or whatever will cause so much change in
thickness when it settles it exceeds the amount of stretch the stud has to
clamp with.  I have read that
  here it is drilled into any truck driver that wheels must be re-torqued
within something like 100 miles after any service.  I saw a wheel change
reciept recently and it had a warning hand written on it to re-torque the
wheel within 100 miles.
Oiling threads is a good thing and will give a more accurate stretch.
Torque has to be adjusted for oiled threads.  Rod bolts are always supposed
to be oiled and they get some crazy stresses without coming loose.
Whatever force that loosens the nuts on one side only matters in making them
fall off after they are already loose.  It isn't enough to make any
difference on a tight nut.
I use anti-seize on my truck but it has the old Budd system.  It's a 1997
model.
BTW he didn't say to only tighten the greased fittings finger tight.

Joel McGregor



-------- Original message --------
From: roboman91324--- via VirtualVairs <virtualvairs at corvair.org>
Date: 9/27/18 10:21 PM (GMT-06:00)
To: Hugo at aruncoaches.co.uk, virtualvairs at corvair.org
Subject: Re: <VV> Fuel Leak

Hugo,

Please excuse my last post.  Mechanical precession is exactly what is going
on with left-side lug nut loosening.  I assumed you were talking about
precession as it pertains to the dynamics of rotating mass.  I. E.
gyroscopic precession.  I have always known it as epicyclic fretting.

By the way, mechanical precession is still a concern but the deeper tapered
lug nuts added just enough friction to compensate.  In addition, the taper
(acorn) itself, not just the added contact area, has been the solution to
the issue in two ways.  First, the taper acts as a wedge which increases the
applied force "N" in the frictional force equation.  Second, the taper
allows for different diameters at different points of contact.  These
interesting tricks of Physics were a game changer.

Again, my apologies,

Doc

PS:  I believe the rest of my posts to be accurate but you never know.
_______________________________________________
This message was sent by the VirtualVairs mailing list, all copyrights are
the property
of the writer, please attribute properly. For help,
mailto:vv-help at corvair.org
This list sponsored by the Corvair Society of America,
http://www.corvair.org/
Post messages to: VirtualVairs at corvair.org
Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs
Archives: http://www.vv.corvair.org/archive.htm
_______________________________________________
_______________________________________________
This message was sent by the VirtualVairs mailing list, all copyrights are
the property
of the writer, please attribute properly. For help,
mailto:vv-help at corvair.org
This list sponsored by the Corvair Society of America,
http://www.corvair.org/
Post messages to: VirtualVairs at corvair.org
Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs
Archives: http://www.vv.corvair.org/archive.htm
_______________________________________________

_______________________________________________
This message was sent by the VirtualVairs mailing list, all copyrights are 
the property
of the writer, please attribute properly. For help, 
mailto:vv-help at corvair.org
This list sponsored by the Corvair Society of America, 
http://www.corvair.org/
Post messages to: VirtualVairs at corvair.org
Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs
Archives: http://www.vv.corvair.org/archive.htm
_______________________________________________ 



More information about the VirtualVairs mailing list