Re: trailing arm bolts

[SHartDP@xxxxxxx]

Having been into off-road/desert racing for a while, and having some experience in that sort of buildup (before my unlce rubbed off on me and I caught the alfa bug), has taught me to be overkill in any and all ways possible on my cars.  I would definately spend the extra pennies and buy grade 8 or metric equivalent bolts.  Grade 5 bolts are softer and will bend easily.  Grade 8 bolts are harder, and will break, but only after a MUCH greater load has been put on them.  A load that I highly doubt an alfa will ever see.  In the trailing arms of the race trucks we use grade 8 bolts as a minimum.  If we can afford um aircraft bolts are used.  BUT, the trailing arms on an off road truck take much more abuse then an alfa.  I have never seen a grade 8 bolt corrode, as they come cadmium/zink plated.  Some grade 5 bolts are not, and I would assume they would corrode easier.  I would like to see if there is info or proof out there showing grade 8's corrode more as I use them a lot.

Just remeber - those trailing arms are what is holding you up in the rear.  Loose one of those and the situation could get ugly very quickly.  Is it worth the risk to save a couple bucks?

Steve Hartman
71 GTV - Euro - for sale
72 GTV - Resto project
Custom turbular frame race truck - 30% done
Nasty Rice rocket = daily driver
In a message dated 4/15/2003 12:01:05 PM Eastern Standard Time, owner-alfa-digest@domain.elided writes:

> Alfa Digest,
> 
> My chassis end trailing arm bolts are marked 9.8 and
> the axle end are 8.8.  SAE handbook says 9.8 are 9%
> stronger than SAE grade 5 and 8.8 are equivalent to
> SAE
> grade 5.
> 
> So going to SAE grade 8 is too much and at least
> something else to consider, you must have the arm
> bushing bear on the shank of the bolt only which means
> that finding a standard gr. 8 will be hard, Carroll
> Smith pointedly says NO gr. 8 bolts on race cars, and
> I think gr. 8 maybe more suseptable to corrosion
> cracking (it is under the car afterall) but maybe a
> materials engr can help us here.
> 
> Finally, metric bolts are available in all grades and
> hardnesses at any good fastner/industrial hardware
> store.  Stay away from Fastenall and any common
> hardware store. The Fastenall people here in Columbus
> are somewhat clueless about metric and commom hardware
> stores will not have the diameters needed.
> 
> Doug Brown
> Alfa racecar #36
> And a couple others
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