I was going to replace the old, OEM bolts with new Grade 8 splitwashers,
nuts and bolts, but noticed something I hadn't considered before.? The
OEM bolts have a long--about 3/4- inch--smooth shank, and only a
half-inch or so of thread.? But, if you go a hardware store to buy Grade
8 in the same, or slightly longer, length you won't find bolts this
short with that much smooth shank.? I noticed when removing the bolts
that they seemed to be a pretty tight fit in both the rotor and hub
holes; I now think that this is purposeful as having tightly fitted,
smooth bolt shanks probably help prevent any sheering motion between the
rotor and hub.? Having a fully-threaded bolt would not prevent sheering,
and the threads might cause fretting on the rotor and hub holes.? This
would be similar to, but different in practice, to the 'dowel' bolts
used in mating bellhousings to the rear engine plate.? Now, I think I
either need to reuse the OEM bolts or buy longer, Grade 8 bolts with
more shank and cut them to size.
No point, just an observation.
Bob
On 8/27/2017 11:01 AM, Bob Spidell wrote:
> I'll be installing new rotors and pads on my BJ8's front disks, and I
> have the kind of question only a really anal-retentive person would
> ask: Do the bolts that affix the hub to the rotor go in bolt head
> outside, or inside; i.e. with the bolt head, or nut, against the hub
> flange?? It seems like the bolt head should be outside, but when I
> bought the car the nuts were on the outside.
>
> Bob
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