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Greg that is strange, rear brakes usually just hang-out back there & do th=
eir thing, once all is established, and fine-tuned with the balance bar.Ass=
uming that the sliders are free, springs good, leading/trailing shoes corre=
ct, I don't see a problem, it's all pretty basic.
With a .70 master on the rear you would actually have less pressure to the =
rears, less braking/heat.The shoes do swell a little when hot, 2-3 clicks o=
ff initially should do it though.Looking at the big picture, what started t=
he problem, ie changes to the system?Also have you tried it w/o the prop va=
lve, or did the problem exist prior?Do you have any gross bias adjustment i=
n the balance bar?
Glen Efinger
=20
=20
-----Original Message-----
From: Greg Blake via Fot <fot@autox.team.net>
To: Fot <fot@autox.team.net>
Sent: Fri, May 7, 2021 4:00 pm
Subject: [Fot] Rear brake help needed
=EF=BB=BF <!--#yiv4690012249 _filtered {} _filtered {}#yiv4690012249 #yiv46=
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red {}#yiv4690012249 ol {margin-bottom:0in;}#yiv4690012249 ul {margin-botto=
m:0in;}-->Fellow racers and breakers of parts, =C2=A0 This past weekend we=
had wonderful racing at Eagles Canyon Raceway.=C2=A0 Ownership turned over=
a couple years ago and they have finished a multi-million dollar renovatio=
n of the track, it is truly amazing now.=C2=A0 ECR has always been high on =
my list because of its potential with the natural terrain, but the lack of =
good construction methods had held it back since it opened.=C2=A0 That has =
all been corrected now and it is truly amazing=E2=80=A6well enough on that =
for now. =C2=A0 My problem For the past two years I have not been able to =
finish a race weekend w/o completely destroying my rear brakes.=C2=A0 Usual=
ly related to heat build up that manifests as a blown wheel cylinder or bra=
ke shoe linings that start cracking and chuncking off the shoe causing furt=
her rapid wear.=C2=A0 This last weekend, I had a total rapid failure of the=
rear brakes when the right rear cylinder let go under hard braking from 10=
0+ mph, I may have blown another seal in the drivers compartment when that =
happened, but will spare those details.=C2=A0 Luckily, my dual masters allo=
wed me to get the car slowed reasonably with just the front brakes.=C2=A0 F=
or any of you that 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 f=
ails.=C2=A0 The balance bar rotates significantly to the side that has zero=
resistance.=C2=A0 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 experie=
nce that I=E2=80=99d rather not repeat again. =C2=A0 My setup Twin Wilwood=
0.7 master cylinders with a custom balance bar.=C2=A0 Stock front TR6 cali=
pers 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).=C2=A0 I also run a hydraulic=
proportioning valve to be able to fine tune the rear hydraulic pressure.=
=C2=A0 I was running with the aluminum rear drums until I destroyed the lin=
ings last year in one of the incidents when the rear shoe linings cracked a=
nd broke completely off allowing the shoe to cut groves into the drum linin=
gs. My routine setup is to put the car on jack stands to adjust the brakes.=
=C2=A0I start by running the rear drum shoe adjusters in until I perceive =
slight drag, then back off two clicks.=C2=A0 Then I adjust the rear mechani=
cal bias with the balance bar until I have the front and rear brakes engagi=
ng (dragging) at approximately the same point of pedal travel.=C2=A0 I then=
fine tune the adjustment to dial back the rear bias until I can threshold =
brake at speed and lock the fronts slightly before I lock the rears.=C2=A0 =
This allows me to trail brake with confidence that I=E2=80=99m not going to=
swap ends because of too much rear brake. =C2=A0 I have used stock, porti=
field, and TSI drum linings all with the same results. =C2=A0 I=E2=80=99m =
looking for a couple things from the group (no disc conversion ideas please=
): =20
- What is wrong with my rear brake setup and adjustment approach?
- What is your setup and adjustment approach?=C2=A0
- 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 thi=
nk we have real junk on the market today.=C2=A0 I have a theory that the sl=
iding wheel cylinder assemble is part of the root cause of my failures, alo=
ng with heat.=C2=A0 The piston and seal are dealing with some severe side l=
oading once the cylinder starts sliding around to do its job and I don=E2=
=80=99t think it is up to the task, especially what we get these days.=C2=
=A0 Has anyone modified their backing plates and shoes to use a modern day =
twin piston wheel cylinder that is bolted to the backing plate?=C2=A0 Or ha=
s anyone ditched the TR drums all together for another 9=E2=80=9D or 10=E2=
=80=9D drum backing plate and guts from another source.=C2=A0 I=E2=80=99m o=
pen to all drum brake ideas at this point.=C2=A0 I=E2=80=99m really tired o=
f not racing because of rear brake failures.=C2=A0
=C2=A0 Sorry for the long post and thanks in advance for your ideas.=C2=
=A0
Greg=C2=A0_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
m
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<div style=3D"color:black;font: 10pt Arial, Helvetica, sans-serif;">
<div> <font size=3D"2">Greg that is strange, rear brakes usually just hang-=
out back there & do their thing, once all is established, and fine-tune=
d with the balance bar.</font></div>
<div><font size=3D"2">Assuming that the sliders are free, springs good, lea=
ding/trailing shoes correct, I don't see a problem, it's all pretty basic.<=
br>
</font></div>
<div><font size=3D"2">With a .70 master on the rear you would actually have=
less pressure to the rears, less braking/heat.</font></div>
<div><font size=3D"2">The shoes do swell a little when hot, 2-3 clicks off =
initially should do it though.</font></div>
<div><font size=3D"2">Looking at the big picture, what started the problem,=
ie changes to the system?</font></div>
<div><font size=3D"2">Also have you tried it w/o the prop valve, or did the=
problem exist prior?</font></div>
<div><font size=3D"2">Do you have any gross bias adjustment in the balance =
bar?<br>
</font></div>
<div><font size=3D"2">Glen Efinger</font><br>
</div>
<div> <br>
</div>
<div> <br>
</div>
<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black"><font=
size=3D"2">-----Original Message-----<br>
From: Greg Blake via Fot <fot@autox.team.net><br>
To: Fot <fot@autox.team.net><br>
Sent: Fri, May 7, 2021 4:00 pm<br>
Subject: [Fot] Rear brake help needed<br>
<br>
<div id=3D"yiv4690012249">
<div><br>
<blockquote type=3D"cite">
<div dir=3D"ltr">=EF=BB=BF
=20
=20
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<div class=3D"yiv4690012249MsoNormal">Fellow racers and breakers of parts,<=
/div>
=20
<div class=3D"yiv4690012249MsoNormal"> </div>
=20
<div class=3D"yiv4690012249MsoNormal">This past weekend we had wonderful ra=
cing at Eagles Canyon Raceway. Ownership turned over a couple years a=
go and they have finished a multi-million dollar renovation of the track, i=
t is truly amazing now. ECR has always been high on my
list because of its potential with the natural terrain, but the lack of go=
od construction methods had held it back since it opened. That has al=
l been corrected now and it is truly amazing=E2=80=A6well enough on that fo=
r now.</div>
=20
<div class=3D"yiv4690012249MsoNormal"> </div>
=20
<div class=3D"yiv4690012249MsoNormal"><b>My problem</b></div>
=20
<div class=3D"yiv4690012249MsoNormal">For the past two years I have not bee=
n able to finish a race weekend w/o completely destroying my rear brakes.&n=
bsp; Usually related to heat build up that manifests as a blown wheel cylin=
der 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 let go =
under hard braking from 100+ mph, I may have blown another seal in the driv=
ers compartment when that happened, but
will spare those details. Luckily, my dual masters allowed me to get=
the car slowed reasonably with just the front brakes. For any of you=
that have had this happen before, you understand that with a balance bar s=
etup, you don=E2=80=99t end up with full brakes when
one end fails. The balance bar rotates significantly to the side tha=
t has zero resistance. In my case I=E2=80=99d estimate that I had abo=
ut 20% of my front brakes available to slow the car, like I said, interesti=
ng experience that I=E2=80=99d rather not repeat again.</div>
=20
<div class=3D"yiv4690012249MsoNormal"> </div>
=20
<div class=3D"yiv4690012249MsoNormal"><b>My setup</b></div>
=20
<div class=3D"yiv4690012249MsoNormal">Twin Wilwood 0.7 master cylinders wit=
h a custom balance 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 b=
e able to
fine tune the rear hydraulic pressure. I was running with the alumin=
um rear drums until I destroyed the linings last year in one of the inciden=
ts when the rear shoe linings cracked and broke completely off allowing the=
shoe to cut groves into the drum linings.
My routine setup is to put the car on jack stands to adjust the brakes. &n=
bsp;I start by running the rear drum shoe adjusters in until I perceive sli=
ght drag, then back 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 approximately the same point =
of pedal travel. I then fine tune the adjustment to dial back the rea=
r bias until I can threshold brake at speed and lock the fronts slightly be=
fore I lock the rears. This allows me
to trail brake with confidence that I=E2=80=99m not going to swap ends bec=
ause of too much rear brake.
</div>
=20
<div class=3D"yiv4690012249MsoNormal"> </div>
=20
<div class=3D"yiv4690012249MsoNormal">I have used stock, portifield, and TS=
I drum linings all with the same results.</div>
=20
<div class=3D"yiv4690012249MsoNormal"> </div>
=20
<div class=3D"yiv4690012249MsoNormal">I=E2=80=99m looking for a couple thin=
gs from the group (no disc conversion ideas please):</div>
=20
<ol style=3D"margin-top:0in;" type=3D"1" start=3D"1">
<li class=3D"yiv4690012249MsoListParagraph" style=3D"margin-left:2.25pt;">W=
hat is wrong with my rear brake setup and adjustment approach?</li><li clas=
s=3D"yiv4690012249MsoListParagraph" style=3D"margin-left:2.25pt;">What is y=
our setup and adjustment approach?
</li><li class=3D"yiv4690012249MsoListParagraph" style=3D"margin-left:2.25p=
t;">Do you like the amount of rear brake you get with your approach or is i=
t a compromise to keep the brakes from failing?</li><li class=3D"yiv4690012=
249MsoListParagraph" style=3D"margin-left:2.25pt;">Lastly, I hate our wheel=
cylinders, its is a terrible design and I think we have real junk on the m=
arket 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 se=
al are dealing with some severe side loading once the cylinder starts slidi=
ng around to do its job and I don=E2=80=99t think it is up to the task, esp=
ecially what we get these days. Has anyone modified
their backing plates and shoes to use a modern day twin piston wheel cylin=
der that is bolted to the backing plate? Or has anyone ditched the TR=
drums all together for another 9=E2=80=9D or 10=E2=80=9D drum backing plat=
e and 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 be=
cause of rear brake failures.
</li></ol>=20
<div class=3D"yiv4690012249MsoNormal"> </div>
=20
<div class=3D"yiv4690012249MsoNormal">Sorry for the long post and thanks in=
advance for your ideas. </div>
</div>
</div>
</blockquote><br>
<div>Greg </div>
</div>
</div>
_______________________________________________<br>
<a ymailto=3D"mailto:fot@autox.team.net"; href=3D"mailto:fot@autox.team.net"=
>fot@autox.team.net</a><br>
<br>
<a href=3D"http://www.fot-racing.com/"; target=3D"_blank">http://www.fot-rac=
ing.com</a><br>
<br>
//www.team.net/donate.html</a><br>
Archive: <a href=3D"http://autox.team.net/archive"; target=3D"_blank">http:/=
/autox.team.net/archive </a><a href=3D"http://www.team.net/pipermail/fot"; t=
arget=3D"_blank">http://www.team.net/pipermail/fot</a><br>
bog1@aol.com" target=3D"_blank">http://autox.team.net/mailman/options/fot/f=
ubog1@aol.com</a><br>
<br>
<br>
</font></div>
</div>
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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
--===============2252578847752441147==--
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