Date: Sat, 17 Dec 2005 03:03:22 -0800
Reply-To: Robert Fisher <refisher@MCHSI.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Fisher <refisher@MCHSI.COM>
Subject: Re: removing frozen lug nuts / bolts ?
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
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You don't tug on Superman's cape, you don't spit into the wind... : )
Cya,
R
----- Original Message -----
From: "Marc Sayer" <marcsayer@COMCAST.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, December 16, 2005 9:22 PM
Subject: Re: removing frozen lug nuts / bolts ?
> Sorry, he's dead right. Torque values are generally given c&d (clean and
> dry) unless otherwise stated. That's an engineering standard. Any time
> you alter the coefficient of friction between components in a fastener
> system that relies on torque to set clamping load, you are changing the
> clamping load and fastener stretch levels. Anything that will increase
> the friction between the fastener components, such as rust for example,
> will lead to a decrease in clamping load and fastener stretch for a
> given torque value. Conversely, any lubricant that reduces friction in
> the system will lead to excessive clamping loads and fastener stretch
> for a given torque value. All fasteners rely on their elasticity to
> clamp the load reliably. If you stretch a fastener beyond its elastic
> limits, the fastener is ruined. Using a torque value works because the
> amount of stretch for that fastener is known for those conditions (i.e.
> friction levels) at that torque value. The only way to know just how
> much to alter the torque value when the friction value is changed (such
> as when a lugnut/bolt assembly is coated with anti-seize) is to use a
> stretch gauge on a handful of test subjects. Once you determine what
> torque value gives the proper stretch value, you are all set, as long as
> you use the exact same spec fasteners for the final assembly.
>
> For a torque value to do what it is designed to do (in terms of
> fasteners), it must be achieved under the correct circumstances. Clean
> and dry (unless otherwise specified), undamaged or distorted threads,
> with the original finish and material specs, and arrived at dynamically
> (with the torque wrench in motion). This is the only way to ensure the
> relationship between the torque value and the stretch value will remain
> unaltered. And achieving the proper stretch value is the only way to
> achieve the proper clamping load.
>
> Now lots of folks have "gotten away" with all sorts of things in regards
> to fasteners, but that doesn't mean it's right or safe. Folks have been
> reusing rod bolts and head bolts for years when many were designed to be
> single use. Most folks reuse "locknuts" even though most are designed to
> be single use and many also require the use of new bolts each time as
> well. And they seem to get away with it, sort of. Ever wonder why most
> folks can not get the same mileage out of their rebuild that the factory
> got from the original motor? This is often one of the reasons. Though it
> is seldom clear as to why a fastener "gave out" or that a fastener was
> responsible for a specific failure. For example, If a headbolt is
> stretched beyond its elastic limit, you may not see the connection
> between the "bad head gasket" and the fastener, but it's there. The bolt
> may look fine, it may even torque properly, but under load, at operating
> temps, it is not clamping the way the other headbolts are, and it is
> causing the head and block to warp. Here's another one, brakes failing
> sooner than expected? It could be the hub is being distorted because the
> lugnuts are being over tightened by being torqued "wet" (lubricated)
> when the spec is for dry.
>
>
> Mark Tuovinen wrote:
>
>>I respect your knowledge, particulary as it applies to vanagons. Your
>>input when list members put forth their questions always makes sense and
>>reflects an understanding that can only come from years of experience.
>>However I do disagree with your opinion on the use of Anti-Seize on lug
>>nuts or bolts. I know plenty of technicians locally that have used it
>>without a problem for decades, I have on occasion applied it myself. Do
>>you have any data to back up your assertion that the torque needs to be
>>reduced when using it?
>>
>>Here most people remove their rims twice a year for the removal and
>>installation of snow tires and I have NEVER seen anyone replace their
>>lugnuts as a consumable item. I do sell more lug nuts and wheel studs in
>>the Spring and Fall, but not a huge amount, just enough to cover the ones
>>stripped, broken, cross threaded, or lost by the underpaid and over worked
>>technicians employed at the local tire vendors. At the rate that you
>>mention most people in my area would be purchasing new nuts every two
>>years and I should be selling a lot more of them then I currently do.
>>
>>Again, I am not trying to offend or start a flame war, just relaying my
>>experiences on this topic, and seeking to learn more from anothers
>>perspective.
>>
>>Mark in AK
>>Assistant Parts Manager
>>Continental Honda
>>Continental Acura
>>
>>P S I love the trailer hitch, just wish that summer wasn't another 5 1/2
>>months away so I could use it
>>
>>
>> ----- Original Message -----
>>From: Dennis Haynes <dhaynes@OPTONLINE.NET>
>>Date: Friday, December 16, 2005 3:54 pm
>>Subject: Re: removing frozen lug nuts / bolts ?
>>To: vanagon@GERRY.VANAGON.COM
>>
>>
>>
>>>Anti- Seize on lug nuts or bolts? Now there's a recipe for disaster.
>>>When using lubricants of this type, the torque needs to be reduced by
>>>some 40 to 50% to keep the stud or bolt from being over stretched. Lug
>>>nuts are consumables and should be replaced after 3-5 times of
>>>use. The
>>>German stuff seems very forgiving. The Japanese and American stuff is
>>>not.
>>>
>>>Dennis
>>>
>>>
>
> --
> Marc Sayer
> Journalist, Photographer, Dog Trainer (APDT member #062956)
> Board member - Western States Great Dane Rescue Association
> Director of Operations & Training - Deaf Dane Rescue Inc.
> Springfield, OR USA
>
> My Homepage - http://gracieland.org
>
> Deaf Dane Rescue Homepage - http://gracieland.org/DaneRescue/
>
>
>
> --
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