Stretch bolts?

[cwass99@rogers.com (cwass99@rogers.com)]

     I hesitate to resurrect a somewhat dead thread, but I've been gleefully
perusing my new Bentley and I've noticed a couple things.  In several areas of
the book, especially in the sections covering suspension, there are a lot of
mentions about not reusing fasteners.  Interestingly, there is no such mention
anywhere near discussions about removing/replacing the cylinder head that I
found.
     I guess the question becomes, exactly where does VW state the head bolts
are stretch bolts and not to be reused?  Having asked the question, I agree,
for the cost, replacing any major fasteners (head bolts, load bearing fasteners
in suspension, etc) is a very good idea.

Cheers,
Colin

On 23-May-2002 Larry wrote:
> Jonas-
>   I have to agree with you on the lack of definite "proof" one way or the
> other.  Someone, Meze I think, mentioned experimenting with some head bolts
> he has, to determine if the bolt actually elongates during the standard
> tightening method.  I hope he does it and reports back.....
>  You are also correct  when you say new bolts are worth the few extra $$.  I
> would never advocate saving pennies at the risk of multi-dollar failure.  If
> accepting the belief that the bolts in question are only good for one use
> will save someone from a fragged engine/clutch/etc, then I'm all for letting
> them believe it.
> No, I didn't realize I'd taken this off-list.  With your permission, I'll
> return it.  If seeing our (sometimes differing) opinions can help someone in
> some way, well, that's what this list is for.
> It's been good  discussing this with you.  Truly.....
> I have no way of scanning the article, but you may be able to read it
> online!  Try www.assemblymag.com , May 2002
> The Fastening feature.
> Later!
> 
> Larry
> 
>>
>> > Jonas-
>> >
>> > --------What is your source?--------
>>
>> Well I must confess that it is only every reputable VW mechanic I've ever
>> spoken to. But I'm still digging to find the info in official VW
>> publications. Stay tuned (pun intended)
>>
>> > ------I, too, trust the engineers, and use the procedure they have
>> > developed.  From the facts that I know of, that procedure does not
>> > permanetly stretch our bolts-------
>>
>> Do you have any facts beyond the article in "Assembly"? If so then great
> and
>> very interesting, it's just that your original post made it sound like you
>> read the article and based your statement on it's generalized fastener
>> procedures. I'd love to see someone test the VW bolts to see weather or
> not
>> they reach the yield point. That would settle it.
>>
>> >> IMHO it would be unwise to dismiss the clear directions from VW based
> on
>> >> the findings in "ASSEMBLY" magazine
>>
>> >> $30 is not worth it for me.
>> >
>> > ------I have no problem with your position. It's probably not worth it
> to me
>> > either!  All I am saying is that there is very compelling evidence that
> the
>> > aforementioned bolts (head, pressure plate, rod, oh, and crank
> sprocket)are
>> > NOT tightened past their yield point and are perfectly re-useable, if
> you
>> > are so inclined.  Peace!------   Larry  sandiego16V
>>
>> I feel that the question is unsettled, at best. I certainly have _zero_
>> physical evidence, and common belief could be very wrong. You raise a good
>> question in "Are the VW 12point head bolt, rod bolt and PP bolts true
>> stretch bolts, or can they be reused?" and the topic deserves a gool look.
>>
>> But all I'm saying is that I have not seen any compelling evidence yet
> that
>> they are _not_ stretch bolts. Anecdotal evidence of people doing it
> "without
>> problem" is irrelevant, and I think the article in "Assembly" is _much_
> too
>> generalized to be applied to our situation. It's written from a design
>> aspect, right, not for the average end-user? Maybe you could scan the
>> article, I'd be interested in reading it.
>>
>> The biggest problem that I see with this is that most people on the list
> are
>> looking to save money on their automotive repair, and are in it for the
> long
>> haul. Even if the bolt is tightened past the yield point, it may very well
>> "work" once or twice more, but what happens on the 10th time the bolt is
>> used? Catastrophic failures are a pisser. Head bolts are one thing, but a
>> Pressure plate coming loose at redline would be very ugly.
>>
>> But keep up the good work. Eventually we'll get to the bottom of this.
> Even
>> if we have to pool our money together to buy that $15k tool to do the damn
>> measuring ourselves. -wait- we're Scirocco owners, that'll never happen.
>:-)
>>
>> Jonas
>>
>> PS. Did you intend to bring this off list, or was that a mistake. I have
> no
>> problem with either way, but some people on the list may benefit from our
>> conversation. I've left it off list for now, in case that was your intent,
>> but feel free to cc the list on any future replies, if you want.
>>
>>
> 
> 
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-- 
Cheers,
Colin

If you can read this line, you're probably not illiterate.