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Alternator bolts...98 Tbird
First off, I've recently returned to the saddle after a few years off & just bought a 98 Tbird....
....and I want to say BIG thankyou to everyone who's been posting away on all the topics esp the tech ones....what can I say...a massive help !
And before I launch into my ruminations, I have to say what fantastic bikes these are - just fekin' love it !...as they say hearabouts.
Yes, not only have I just joined the Tbird club I'm another proud affiliate of the sheared-Alternator-shaft-bolt-club, lesser-post-VIN-566blah-not-clutch-side-section....
So....after reading all your posts....I offer de following 'umble torts (I'm from Ireland btw)....
Sheared bolt stuck in Alternator shaft has so far resisted removal by 'easy out' stud/screw remover tool....
so....I plan to take said Alternator to a machine shop & have the shaft drilled & tapped for a size up - M8, as suggested...
....tho' I have in mind to use an 8.8 strength bolt not the 10.9 of the original M6. My thinking here is that I suspect the bolt shears mainly due to the relatively large sideways (90deg to axis) movement allowed by the combination of big space between the end of the shaft threads & a bellvedere washer which also allows it a bit of movement.
This all happening in a shock load kind of way whilst the more 'brittle' 10.9 is torqued pretty close to it's max spec.
8.8 has about 20% less tensile strengh than 10.9 but the M8 has about 75% more area, using the following table of torque specs, in FOOT POUNDS....
Bolt size Grade 8.8 Grade 10.9 Grade 12.9
6mm 7 10 12
8mm 17 24 29
.....I'm planning to torque up the M8 to about 13 ft lbs & allow a bit of sideways 'give' where the bolt is not fully 'sprung' (stretched) lengthways
It follows from what I've said that the even more brittle 12.9 in M6 size would not be much improvement or even worse than than the original, as a possible upgrade....
Any advice on this idea gratefully recieved ! (& apologies if ye are all bored to death by this issue..!)
Best,
Mike
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