Date: Thu, 14 Jun 2012 12:29:07 -0500
Reply-To: JRodgers <jrodgers113@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: JRodgers <jrodgers113@GMAIL.COM>
Subject: Re: warning regarding GoWesty alternator bracket kit
In-Reply-To: <C95FE8BD-E860-4048-880A-62072B14EA5A@shaw.ca>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Just asking in general, since an earlier post commented on stripping the
threads on the new alternator bracket bolt. Stripped threads and
incorrect torque often go together. In my view, to tighten any nut/bolt
combination, the torque value for that combination should be known, then
if the threads fail - or the bolt breaks - you have a starting point to
fix the problem, and not repeat it.
John
On 6/14/2012 9:52 AM, Alistair Bell wrote:
> so John, what bolt exactly are you asking torque specs for?
>
> alistair
>
>
> On 2012-06-14, at 7:41 AM, JRodgers wrote:
>
>> So Bentley does in fact have a specified torque value for the bolt in question. But that is for a factory supplied bolt. When bolts come from other sources they are always suspect until properly identified by the marks on the bolt head and cross referenced to a book of standard torque values for the particular bolt in question. Even then, unless you know the source, you may be getting cheap bolts made in 3rd world countries where alloy composition is of no consequence - only the money from sales. (almost sounds like the USA these days)
>>
>> Back in my aviation heyday every nut, bolt, washer, rivet, what have you had to have source records or it didn't get used. That way if an engine fell off - failed parts could be traced to their source and the problem fixed, whether bad alloy or crappy mechanic work. Would not want to blame a parts manufacturer if a mechanic parked his bubble gum in a bad spot.
>>
>> A number of years ago a big airliner crashed after losing an entire engine and pylon in flight. The engine mount bolts were thoroughly sourced, checked, tested, and the alloy composition tested. The bolts should not have failed, but they did. Why? In the end, it was found that it was the mechanics fault. Instead of following procedure, they were short cutting and using a fork lift to make it easier to make an engine change. This procedure over stressed the bolts and caused them to fail in flight. Bad business. But being able to source those bolts quickly and test them saved everybody a lot of hassle.
>>
>> Regards,
>>
>> John
>>
>> On 6/14/2012 9:02 AM, Alistair Bell wrote:
>>>
>>> Now I recall the name of the book, Bentley!
>>>
>>> and its 25 Nm, not 28
>>>
>>> :)
>>>
>>> alistair
>>>
>>>
>>>
>>> John,
>>>
>>> I seem to recall that there is some sort of book or manual that has information about this, can't quite recall the name of it, something like Buntley, Bendy, Brimley?
>>>
>>> 28Nm/ 18 ft lbs
>>>
>>> :)
>>>
>>> alistair
>>>
>>>
>>>
>>>
>>> On 2012-06-14, at 6:00 AM, JRodgers wrote:
>>>
>>>> Is there a specified or a standard torque value for the bolt?
>>>>
>>>> John Rodgers
>>>>
>>>> On 6/13/2012 11:42 PM, Dennis Haynes wrote:
>>>>> It is very important for that lower alternator bolt to be properly
>>>>> tightened. If you can adjust the belt without loosening it, it is probably
>>>>> too loose. Give up the carriage bolt and use a P.C. 10.9 bolt, nut and
>>>>> washer. Yes washers also come in differing grades. As for the bracket studs,
>>>>> the nuts should match the grade of the stud.
>>>>>
>>>>> Dennis
>>>
>>>
>
>
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