J&E wrote:
> Taken from 1-10-00 TR Digest List
> >Hi Karl,
> I'm copying this to the list as it may be unclear for others as well.
>
> If the center bore was mis-matched, and so were the wheel stud holes, it
> would be
> humanly impossible to properly center the drum upon reinstalling the
> wheel. As you
> say, even slight error would result in pedal pulsation, if not brake
> overheating from
> continually dragging for part of each rotation.
>
> Actually, the center bore that fits over the axle nut is the same for
> both drums, and
> there is no problem with drums locating on center for either
> combination. The
> difference is in the shank of the wheel stud. While both cars take the
> same 7/16 - 20
> lug/stud, the shank on the solid axle cars is stepped to about 9/16 at
> the hub and the
> holes in the drum for the studs are correspondingly larger. With that
> in mind, if you
> were to install a TR-4 drum onto a TR-6, the drum would locate properly
> on the hub's
> center, but you'd have axial shift about the extra clearance in the stud
> holes. In
> this situation, the only positive location for the drum would be the
> retaining
> screws. True, friction between the drum, hub, and wheel would and
> should probably
> keep it from shifting. But if it doesn't, the drum may slip, especially
> in a panic
> stop the forces involved are quite high. If the drum does slip, all the
> panic-braking
> force would be transmitted throught the locating screws and the they
> might shear under
> such stresses. This could result in potential damage to the drum or
> hub.
>
> Of course, you could run the combo without the screws, and just allow
> the drum to
> shift on the clearance around the stud holes, but I sure wouldn't want
> to take any
> chances like that with my brakes. Regards, -Brian Schlorff <
> -----------------------
> Hi List!
> Question: Why can't some type of "pipe or tubing" be installed as a
> "sleeve" to take up the space between the wheel stud & drum hole for the
> wheel stud. Thus being a "bushing" of some type? Also, if this was to be
> done would Stainless Steal be an accpetable material? If not, then what
> material would be accpetable? Wouldn't I be a good idea to coat the
> inside & outside of this material with an anti-seize grease coating for
> easy removial of the drum? -Cosmo Kramer
Yes, sleeves could be made up if you really had to run a TR-4 drum on a TR-6,
but just
be very clear that it is marked in some way so if someone else takes the drum
off,
they know to look for the spacers and not to overlook them on reinstallation.
The
only time this would be an issue is if you were to put TR-3/4 drums on a TR-6.
Again,
I strongly urge you not to take ANY chances with brakes and just get the right
drums.
TR-6 drums are very easy to find. The only time I could see a real need for
this
procedure would be if you were to get a set of Alfin's that were once on an
early car
and you are now trying to fit them to a late car. If you're doing that, just
have
them drilled for the correct size stud at a 45 degree offset - then you'd
effectively
have dual pattern drums. Alternatively, you should be able to find a machine
shop to
weld the holes up and redrill them to the correct size. If you get the 240Z
drums,
they'll be the smaller size to begin with and you can just machine them to fit
your
particular application.
Regards,
Brian Schlorff '61 TR-4 '64 TR-4 '72 TR-6 '79 Spit
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