In a message dated 3/15/99 9:28:53 AM Eastern Standard Time,
dynamic@transport.com writes:
>
> Dan Masters wrote:
> >BTW, these calipers will give a 10 increase in braking pressure for a
given
> >pedal pressure, and have about 50% more pad area than stock.
>
> I like the 4-pot caliper idea. Now I gotta convince my wife that my
> current calipers are shot!! (he, he!!) But wouldn't the increase in
> pressure AND pad area increase the danger of fade unless something is done
> to the rotors? Seems like you'll have 50% LESS rotor exposed to cooling
> air with a 50% larger pad area exerting 10% more pressure.
Pete,
The PADS have 50% more area, which will create only a small % decrease in the
ROTOR area exposed for cooling. For a given braking force, the heat generated
will be spread over a 50% large pad area, so the temperature rise will be less
than with the srock brakes. I would suspect the reduction in temperature rise
in the pads would more than offset the reduction in exposed rotor area.
> How do you like my idea (as if it's mine and mine alone!) of having grooves
> machined into the rotors to help dissipate/evacuate the dust/gas/heat?
Unfortunately, I'm not knowledgable enough to comment. As much as it is done
on competition cars, it must have merit. I still have smoe more research to do
on this topic.
> Well, I can only say that I wish I had been a little more aware of
> something like this the last time I had my brakes off. Way back when when
> I rebuilt my suspension, I went down to the fastener store and bought all
> new grade 8 bolts to assemble the suspension with, including the caliper
> fastening bolts. They are 7/16" (fine thread) and athough they are a
> standard off-the-shelf bolt, they seem to fit just fine with no slop. I'm
> sure I would've noticed if there WAS some slop in there!! (I HOPE I
> would've noticed, anyway!!)
The difference between the bolts you used and those supplied by TRF (and the
factory, I assume) is in the length of the unthreaded shank. On a standard,
off-the-shelf bolt, with a length of 1 3/4 inches, the unthreaded shank is 3/8
inches. The correct (?) bolt has an unthreaded shank length of 3/4 inches,
with an overall length of 1 3/4 inches. This means that most of the bolt that
is within the caliper itself is unthreaded. How much difference this makes I
don't know. I only know that in most cases where precise location is
important, the factory used special long shank bolts. For example, the rotor
attachment bolts have a longer shank than standard, but of course, getting the
rotor perfectly centered is much more important than precisely locating the
brake rotors ( a standard bolt of the length of the rotor attachment bolts has
no unthreaded shank at all - it's threaded for its entire length. The factory
bolt has a shank about equal to the thickness of the rotor).
There may also be some difference in the metallurgy as well, but I've not seen
any reference to it.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://members.aol.com/danmas/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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