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> =EF=BB=BF
> Fellow racers and breakers of parts,
> =20
> This past weekend we had wonderful racing at Eagles Canyon Raceway. Owner=
ship turned over a couple years ago and they have finished a multi-million d=
ollar renovation of the track, it is truly amazing now. ECR has always been=
high on my list because of its potential with the natural terrain, but the l=
ack of good construction methods had held it back since it opened. That has=
all been corrected now and it is truly amazing=E2=80=A6well enough on that f=
or now.
> =20
> My problem
> For the past two years I have not been able to finish a race weekend w/o c=
ompletely destroying my rear brakes. Usually related to heat build up that m=
anifests as a blown wheel cylinder or brake shoe linings that start cracking=
and chuncking off the shoe causing further rapid wear. This last weekend, I=
had a total rapid failure of the rear brakes when the right rear cylinder l=
et go under hard braking from 100+ mph, I may have blown another seal in the=
drivers compartment when that happened, but will spare those details. Luck=
ily, my dual masters allowed me to get the car slowed reasonably with just t=
he front brakes. For any of you that have had this happen before, you under=
stand that with a balance bar setup, you don=E2=80=99t end up with full brak=
es when one end fails. The balance bar rotates significantly to the side th=
at has zero resistance. In my case I=E2=80=99d estimate that I had about 20=
% of my front brakes available to slow the car, like I said, interesting exp=
erience that I=E2=80=99d rather not repeat again.
> =20
> My setup
> Twin Wilwood 0.7 master cylinders with a custom balance bar. Stock front T=
R6 calipers and stock 9=E2=80=9D TR drums with 0.75 wheel cylinders (I=E2=80=
=99ve tried everything from 5/8 up to 7/8=E2=80=9D). I also run a hydraulic=
proportioning valve to be able to fine tune the rear hydraulic pressure. I=
was running with the aluminum rear drums until I destroyed the linings last=
year in one of the incidents when the rear shoe linings cracked and broke c=
ompletely off allowing the shoe to cut groves into the drum linings. My rout=
ine setup is to put the car on jack stands to adjust the brakes. I start by=
running the rear drum shoe adjusters in until I perceive slight drag, then b=
ack off two clicks. Then I adjust the rear mechanical bias with the balance=
bar until I have the front and rear brakes engaging (dragging) at approxima=
tely the same point of pedal travel. I then fine tune the adjustment to dia=
l back the rear bias until I can threshold brake at speed and lock the front=
s slightly before I lock the rears. This allows me to trail brake with conf=
idence that I=E2=80=99m not going to swap ends because of too much rear brak=
e.
> =20
> I have used stock, portifield, and TSI drum linings all with the same resu=
lts.
> =20
> I=E2=80=99m looking for a couple things from the group (no disc conversion=
ideas please):
> What is wrong with my rear brake setup and adjustment approach?
> What is your setup and adjustment approach?=20
> Do you like the amount of rear brake you get with your approach or is it a=
compromise to keep the brakes from failing?
> Lastly, I hate our wheel cylinders, its is a terrible design and I think w=
e have real junk on the market today. I have a theory that the sliding whee=
l cylinder assemble is part of the root cause of my failures, along with hea=
t. The piston and seal are dealing with some severe side loading once the c=
ylinder starts sliding around to do its job and I don=E2=80=99t think it is u=
p to the task, especially what we get these days. Has anyone modified their=
backing plates and shoes to use a modern day twin piston wheel cylinder tha=
t is bolted to the backing plate? Or has anyone ditched the TR drums all to=
gether for another 9=E2=80=9D or 10=E2=80=9D drum backing plate and guts fro=
m another source. I=E2=80=99m open to all drum brake ideas at this point. I=
=E2=80=99m really tired of not racing because of rear brake failures.=20
> =20
> Sorry for the long post and thanks in advance for your ideas.=20
Greg=20=
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<p class=3D"MsoNormal">Fellow racers and breakers of parts,<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">This past weekend we had wonderful racing at Eagles C=
anyon Raceway. Ownership turned over a couple years ago and they have f=
inished a multi-million dollar renovation of the track, it is truly amazing n=
ow. ECR has always been high on my
list because of its potential with the natural terrain, but the lack of goo=
d construction methods had held it back since it opened. That has all b=
een corrected now and it is truly amazing=E2=80=A6well enough on that for no=
w.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><b>My problem<o:p></o:p></b></p>
<p class=3D"MsoNormal">For the past two years I have not been able to finish=
a race weekend w/o completely destroying my rear brakes. Usually rela=
ted to heat build up that manifests as a blown wheel cylinder or brake shoe l=
inings that start cracking and chuncking
off the shoe causing further rapid wear. This last weekend, I had a t=
otal rapid failure of the rear brakes when the right rear cylinder let go un=
der hard braking from 100+ mph, I may have blown another seal in the drivers=
compartment when that happened, but
will spare those details. Luckily, my dual masters allowed me to get t=
he car slowed reasonably with just the front brakes. For any of you th=
at have had this happen before, you understand that with a balance bar setup=
, you don=E2=80=99t end up with full brakes when
one end fails. The balance bar rotates significantly to the side that=
has zero resistance. In my case I=E2=80=99d estimate that I had about=
20% of my front brakes available to slow the car, like I said, interesting e=
xperience that I=E2=80=99d rather not repeat again.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal"><b>My setup<o:p></o:p></b></p>
<p class=3D"MsoNormal">Twin Wilwood 0.7 master cylinders with a custom balan=
ce bar. Stock front TR6 calipers and stock 9=E2=80=9D TR drums with 0.=
75 wheel cylinders (I=E2=80=99ve tried everything from 5/8 up to 7/8=E2=80=9D=
). I also run a hydraulic proportioning valve to be able to
fine tune the rear hydraulic pressure. I was running with the aluminu=
m rear drums until I destroyed the linings last year in one of the incidents=
when the rear shoe linings cracked and broke completely off allowing the sh=
oe to cut groves into the drum linings.
My routine setup is to put the car on jack stands to adjust the brakes. &nb=
sp;I start by running the rear drum shoe adjusters in until I perceive sligh=
t drag, then back off two clicks. Then I adjust the rear mechanical bi=
as with the balance bar until I have the
front and rear brakes engaging (dragging) at approximately the same point o=
f pedal travel. I then fine tune the adjustment to dial back the rear b=
ias until I can threshold brake at speed and lock the fronts slightly before=
I lock the rears. This allows me
to trail brake with confidence that I=E2=80=99m not going to swap ends beca=
use of too much rear brake.
<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">I have used stock, portifield, and TSI drum linings a=
ll with the same results.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">I=E2=80=99m looking for a couple things from the grou=
p (no disc conversion ideas please):<o:p></o:p></p>
<ol style=3D"margin-top:0in" start=3D"1" type=3D"1">
<li class=3D"MsoListParagraph" style=3D"margin-left:2.25pt;mso-list:l0 level=
1 lfo1">What is wrong with my rear brake setup and adjustment approach?<o:p>=
</o:p></li><li class=3D"MsoListParagraph" style=3D"margin-left:2.25pt;mso-li=
st:l0 level1 lfo1">What is your setup and adjustment approach?
<o:p></o:p></li><li class=3D"MsoListParagraph" style=3D"margin-left:2.25pt;m=
so-list:l0 level1 lfo1">Do you like the amount of rear brake you get with yo=
ur approach or is it a compromise to keep the brakes from failing?<o:p></o:p=
></li><li class=3D"MsoListParagraph" style=3D"margin-left:2.25pt;mso-list:l0=
level1 lfo1">Lastly, I hate our wheel cylinders, its is a terrible design a=
nd I think we have real junk on the market today. I have a theory that=
the sliding wheel cylinder assemble is part
of the root cause of my failures, along with heat. The piston and sea=
l are dealing with some severe side loading once the cylinder starts sliding=
around to do its job and I don=E2=80=99t think it is up to the task, especi=
ally what we get these days. Has anyone modified
their backing plates and shoes to use a modern day twin piston wheel cylind=
er that is bolted to the backing plate? Or has anyone ditched the TR d=
rums all together for another 9=E2=80=9D or 10=E2=80=9D drum backing plate a=
nd guts from another source. I=E2=80=99m open to all drum
brake ideas at this point. I=E2=80=99m really tired of not racing bec=
ause of rear brake failures.
<o:p></o:p></li></ol>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Sorry for the long post and thanks in advance for you=
r ideas. </p></div>
</div></blockquote><br><div>Greg </div></body></html>=
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_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
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