Hey, I knew Dave was out there lurking. And it looks like we're in
agreement with our blase attitude about alfin drum liner cracks. And Hardy
too! Wow. People are going to start feeling like they're not ready to race
unless their drums are well cracked. How 'bout it Kas, shouldn't it be a
requirement?
-----Original Message-----
From: Dave Talbott
To: Jack W. Drews; fot@autox.team.net
Sent: 6/17/2003 2:22 PM
Subject: Re: brake drums
Jack:
Having raced 240Z's for some years with rear drum brakes, I can say your
problem is not an isolated one, however it has not usually been cause
for
concern in a race. I have taken many drums off with cracks and clear
evidence of heat, but never actually had the ferrous linings come
adrift.
They are especially subject to cracks as they get close to their maximum
size, the dimension for which is typically cast into the aluminum on the
face.
240Z's in the Improved Touring S-class tend to have a bit more grunt
than
the brake system is designed for, so to assist the overworked fronts,
you
try to bias as much to the rears as you can handle from a driving
standpoint. That usually involves high friction linings for the rears
and
attention to bleeding and adjusting out the rears frequently. You end
up
replacing a lot of shoes, and the drums don't last too much longer than
the
shoes, especially if you take them out of service somewhat before they
enlarge to their maximum dimension. It is a maintenance intensive
approach,
but they do work, and the drums are available through various supply
houses
for not a whole lot of dollars. Ventilating the backing plates as well
as
heat-dispersing coatings on the drums seem to make things last a bit
longer.
Maybe others have different experiences with the potential hazard of the
cracks, but I've never seen a Datsun drum cause any real problems. I do
seem to remember Hardy being very attentive to his drums, of course
Hardy
lavishes lot's of attention on most everything .
Dave Talbott
----- Original Message -----
From: "Jack W. Drews" <vinttr4@geneseo.net>
To: <fot@autox.team.net>
Sent: Tuesday, June 17, 2003 1:42 PM
Subject: brake drums
> My TR4 race car has Datsun 280Z rear brake drums.
>
> This morning I removed and inspected them, and found that one of them
had
> three cracks across the iron friction face. Yuk. I have used these
drums
> for five years and they never even needed turning. I inspected them
last
> winter and did not see cracks at that time, but maybe they were there
and
I
> didn't notice them.
>
> At any rate, be forewarned that this kind of failure can occur. The
thought
> of it happening during a race is not pretty.
>
> uncle jack
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