Date: Wed, 19 Dec 2007 23:31:24 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: nuts in steering linkage and rack
In-Reply-To: <049c01c84292$0f9af0d0$0a00a8c0@OWNERMIKE>
Content-Type: text/plain; charset="iso-8859-1"
Nylon lock nuts are all junk and are only used for low stress, vibration
only applications. When they are used for grade 8 applications, they get
their strength from being unusually tall. The Grade "C" prevailing torque
nut is required to work for 5 cycles. The deformations are usually oval or
three sided and they are usually plated and lubricated for pre load
consistency.
One thing with lock nuts or washers. If the locking action helps at all
the bolted connection has really failed and the only advantage of the
locking action is to prevent the nut or bolt from getting lost. The
connection is still loose and continuous cycle loading will still wear
something out or break the bolt. If the connection is doing its job, then
the locking stuff is not needed.
As for those hardware kits, you are absolutely right.
If you want really good hardware, go find a Lawson distributor. There
perm-plate or Permatorque products are outstanding.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mike
Sent: Wednesday, December 19, 2007 5:54 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: nuts in steering linkage and rack
All locknuts have a prevailing torque. Some are higher than others.
What
exactly are you talking about? You should use a beam or dial-type
inch-pounds torque wrench to measure what the prevailing torque is when
freely spinning the nut down, and then add that figure to the book
requirement's torque specification to be able to fully achieve the final
designed torque of the fastener.
As a fastener is used, the locking tension feature (whether low-temp
nylok, or high-temp crimped all-steel) will become less than the original.
But, it's my personal experience that one or two re-uses is acceptable, as
long as the locking feature still works well. It's easy to tell if it is
still acceptable for re-use.
The nylock ones get cut by the threads after several runs on and off,
and
lose their locking abilities very quickly. Exposure to high temps
(usually
engine or brake use) will melt the nylon and render the locking feature
useless. All-steel locking nuts are either sliced (like
castellations)
and crimped inwards on the end threads to act like a wedge to squeeze the
threads all the way around, or have smaller seperate area that is crimped
on
two sides to squeeze the threads on each side of the bolt. It is possible
to
re-deform the relaxed metal and re-use them indefinitely, but it's more
trouble than it's worth and I can't recommend it.
BTW, those complete engine hardware kits sold to the ACVW crowd,
actually
contain all the wrong types of locking hardware for use on a high-temp
application such as an ACVW. In addition, the washers are not high enough
grade to be correct for this application. Not at all good, can't
recommend
using them. This not new information, just a good time to mention it.
Mike B.
----- Original Message -----
From: "Dennis Haynes" <d23haynes57@HOTMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, December 19, 2007 11:07 AM
Subject: Re: nuts in steering linkage and rack
> Unless specifically designed for the purpose such as a Grade C
prevailing
> Torque locknut, nuts should never be reused in a critcal application.
Most
> of the preload is taken on the first three threads and they will always
> deform when properly torqued. Given the same torque, used nuts will not
> provide the same or consistant tension. High end fastner suppliers can
> demo
> this with a bolt tension gauge. When repalcing, you also need to get the
> proper grade or property class fastners and the bolts, nuts, washers,
need
> to be match or at least suitable. For anything that maters you want at
> least
> P.C. 10.9 including heat treated washers. Grade C locknuts are
lubricated
> and while difficult to run down a bolt, reqiure less final torque to
> achive
> the final clamping load as a standard dry nut.
>
> Dennis
>
>
>>From: Allan Streib <streib@CS.INDIANA.EDU>
>>Reply-To: Allan Streib <streib@CS.INDIANA.EDU>
>>To: vanagon@GERRY.VANAGON.COM
>>Subject: Re: nuts in steering linkage and rack
>>Date: Wed, 19 Dec 2007 10:03:15 -0500
>>
>>The illustration in the Bentley manual specifically indicates the
>>nuts, not the bolts, with the "always replace" admonishment.
>>
>>I looked again and noticed an astersik with a footnote, and it says
>>"self locking nuts". I wonder if these are just nuts pre-treated with
>>thread locker. I looked at the ones I removed and they do not seem to
>>have any "deforming" features that would preclude re-use, in fact they
>>look completely ordinary.
>>
>>Allan
>>
>>Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM> writes:
>>
>> > I don't know about your VW stealership but mine would have a hard
time
>> > finding those bolts in the parts pictures and ordering them. NLA
>>wouldn't
>> > surprise me even. I don't think they are stretch type, but I'm not
>>certain.
>> >
>> > Liability and safety would be the obvious concerns.
>> > 'modern' ?? you're calling a 1980 to 1991 Vanagon 'modern' ??
>
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