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Re: [Fot] squaring pads

To: Phil Gott <vfracing@aol.com>, Phil Gott via Fot <fot@autox.team.net>, ralph hansen <quikrx@yahoo.com>
Subject: Re: [Fot] squaring pads
From: DAVE HOGYE via Fot <fot@autox.team.net>
Date: Sun, 21 Jul 2019 21:10:50 -0700 (PDT)
Delivered-to: mharc@autox.team.net
Delivered-to: fot@autox.team.net
Importance: Medium
References: <202681213.4313576.1563665916801.ref@mail.yahoo.com> <202681213.4313576.1563665916801@mail.yahoo.com> <879919291.2670545.1563719625995@mail.yahoo.com> <0C531DBA-E99E-44EE-AE40-0782D8E40A13@aol.com>
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The more clearance between the slot in the caliper and the pad backing plat=
e the quicker this becomes a problem.   I've measured .010-.012" total clea=
rance on an NOS street pad and as much as .070" on a set of Carbotech pads.=
  The edges of the Carbotech backing plates looked to have been, (were defi=
nitely), ground off on and belt sander or grinder from the factory, right d=
own to the edge of the friction pad and they were out of square by .035".  =
The side of the pad was making contact with the caliper slot.  This immedia=
tely caused problems with the caliper pistons cocking severely.  The piston=
s even left a witness mark in the bore of the calipers.  Not good.  The Car=
botech pads had .070" wear diagonally across the friction surface in a coup=
le of weekends of racing.  Unfortunately, Carbotech made many excuses and d=
enials when I brought this to their attention. =20

If the pad backing plate is held close in the slot, the piston cannot get c=
ocked as severely under hard braking.  Squaring of pad surface may still be=
 desirable at some point, but pay close attention between of the width of t=
he backing plate and the caliper slot. =20

I have found Hawk pads to be made with as close a clearance as factory pads=
 and the same dimension on every order.  No variations.  The Hawk pads also=
 have the same shape as factory pads, more like a pie cut.  Wider at the ou=
ter edge.  This helps compensates for rotor surface speed and reduces uneve=
n wear.=20

I do like the feel of the Carbotechs, but I cannot rely on their quality co=
ntrol.

As you apply the brakes, the piston extends.  If the pad can move greatly w=
ithin the caliper slot, the piston with take the side load, not the backing=
 plate of the pad as it should.  If the backing plate is not square, the pa=
d will also rotate a little.  Definitely not good.

Beware,

Dave H.


> On July 21, 2019 at 12:27 PM Phil Gott via Fot <fot@autox.team.net> wrote=
:
>=20
>     The pads wear unevenly both radially and a bit circumferentially due =
to different surface speeds and friction forces. As the pads wear unevenly =
they =E2=80=9Ccock=E2=80=9D in the caliper and bind up. The more wear, the =
greater the binding.=20
>     Using some sort of a device (surface grinder, drill press etc with a =
good dust collector and mask for the operator) to make the face of the fric=
tion material parallel to the backing plate solves this issue.
>     Yes, this does change the surface of the pad presented to the rotor. =
I do not change rotors as they are in good shape. Any small to microscopic =
irregularities between the two quickly get dealt with during the first sess=
ion out after squaring the pads. This would be the same as putting new pads=
 on the car with the old rotors. Just treat the first few laps as if you ar=
e bedding in new brakes, which to some extent you are (except for temperatu=
re effects).
>     Different from a street machine where rust and grit take their toll i=
n the rotor surface.
>     Phil Gott
>     114 TR4A
>=20
>     Sent from my iPhone
>=20
>     On Jul 21, 2019, at 10:33 AM, ralph hansen via Fot < fot@autox.team.n=
et mailto:fot@autox.team.net > wrote:
>=20
>=20
>         > >         =20
> >         =20
> >         not to rain on the parade but, are you turning the rotors each =
time to make sure they are square also? if not, you now have unmatched surf=
aces - in the old days with good metal rotors I could see a slight advantag=
e, these days with the good pads we get, and soft rotors they wear together=
, you might actually get a very slight increase in surface contact due to t=
he angles and dangles - and, as you machine the rotors you lose mass, the a=
ll important heat sink that makes brakes work....
> >=20
> >         =20
> >         On Saturday, July 20, 2019, 07:19:46 PM CDT, Mathieu W. Huovine=
n via Fot < fot@autox.team.net mailto:fot@autox.team.net > wrote:
> >=20
> >=20
> >=20
> >         =20
> >=20
> >         Squaring up the pads? Please tell me more, I'm still learning. =
Thanks!
> >=20
> >         -Marhieu
> >=20
> >         =20
> >         _______________________________________________
> >         fot@autox.team.net mailto:fot@autox.team.net
> >=20
> >         http://www.fot-racing.com
> >=20
> >         Donate: http://www.team.net/donate.html
> >         Archive: http://autox.team.net/archive http://autox.team.net/ar=
chive http://www.team.net/pipermail/fot
> >         Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/q=
uikrx@yahoo.com
> >=20
> >=20
> >=20
> >     >=20
>         > >         _______________________________________________
> >         fot@autox.team.net mailto:fot@autox.team.net
> >=20
> >         http://www.fot-racing.com
> >=20
> >         Donate: http://www.team.net/donate.html
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rmail/fot
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fracing@aol.com
> >=20
> >=20
> >=20
> >     >=20


=20

> _______________________________________________
>     fot@autox.team.net
>=20
>     http://www.fot-racing.com
>=20
>     Donate: http://www.team.net/donate.html
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fot
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>=20
>=20
>=20


=20

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<!DOCTYPE html>
<html><head>
    <meta charset=3D"UTF-8">
</head><body><p style=3D"font-size: 12pt; font-family: helvetica, arial, sa=
ns-serif; color: rgb(51, 51, 51);">The more clearance between the slot in t=
he caliper and the pad backing plate the quicker this becomes a problem.&#1=
60; &#160;I&#39;ve measured .010-.012&#34; total clearance on an NOS street=
 pad and as much as .070&#34; on a set of Carbotech pads.&#160; The edges o=
f the Carbotech backing plates looked to have been, (were definitely), grou=
nd off on and belt sander or grinder from the factory, right down to the ed=
ge of the friction pad and they were out of square by .035&#34;.&#160; The =
side of the pad was making contact with the caliper slot.&#160; This immedi=
ately caused problems with the caliper pistons cocking severely.&#160; The =
pistons even left a witness mark in the bore of the calipers.&#160; Not goo=
d.&#160; The Carbotech pads had .070&#34; wear diagonally across the fricti=
on surface in a couple of weekends of racing.&#160; Unfortunately, Carbotec=
h made many excuses and denials when I brought this to their attention.&#16=
0;&#160;</p><p style=3D"font-size: 12pt; font-family: helvetica, arial, san=
s-serif; color: rgb(51, 51, 51);">If the pad backing plate is held close in=
 the slot, the piston cannot get cocked as severely under hard braking.&#16=
0; Squaring of pad surface may still be desirable at some point, but pay cl=
ose attention between of the width of the backing plate and the caliper slo=
t.&#160;&#160;</p><p style=3D"font-size: 12pt; font-family: helvetica, aria=
l, sans-serif; color: rgb(51, 51, 51);">I have found Hawk pads to be made w=
ith as close a clearance as factory pads and the same dimension on every or=
der.&#160; No variations.&#160; The Hawk pads also have the same shape as f=
actory pads, more like a pie cut.&#160; Wider at the outer edge.&#160; This=
 helps compensates for rotor surface speed and reduces uneven wear.&#160;</=
p><p style=3D"font-size: 12pt; font-family: helvetica, arial, sans-serif; c=
olor: rgb(51, 51, 51);">I do like the feel of the Carbotechs, but I cannot =
rely on their quality control.</p><p style=3D"font-size: 12pt; font-family:=
 helvetica, arial, sans-serif; color: rgb(51, 51, 51);">As you apply the br=
akes, the piston extends.&#160; If the pad can move greatly within the cali=
per slot, the piston with take the side load, not the backing plate of the =
pad as it should.&#160; If the backing plate is not square, the pad will al=
so rotate a little.&#160; Definitely not good.</p><p style=3D"font-size: 12=
pt; font-family: helvetica, arial, sans-serif; color: rgb(51, 51, 51);">Bew=
are,</p><p style=3D"font-size: 12pt; font-family: helvetica, arial, sans-se=
rif; color: rgb(51, 51, 51);">Dave H.</p><p style=3D"font-size: 12pt; font-=
family: helvetica, arial, sans-serif; color: rgb(51, 51, 51);"><br></p><blo=
ckquote type=3D"cite">On July 21, 2019 at 12:27 PM Phil Gott via Fot &#60;f=
ot@autox.team.net&#62; wrote: <br> <br>The pads wear unevenly both radially=
 and a bit circumferentially due to different surface speeds and friction f=
orces. As the pads wear unevenly they &#8220;cock&#8221; in the caliper and=
 bind up. The more wear, the greater the binding.&#160;<div>Using some sort=
 of a device (surface grinder, drill press etc with a good dust collector a=
nd mask for the operator) to make the face of the friction material paralle=
l to the backing plate solves this issue.</div><div>Yes, this does change t=
he surface of the pad presented to the rotor. I do not change rotors as the=
y are in good shape. Any small to microscopic irregularities between the tw=
o quickly get dealt with during the first session out after squaring the pa=
ds. This would be the same as putting new pads on the car with the old roto=
rs. Just treat the first few laps as if you are bedding in new brakes, whic=
h to some extent you are (except for temperature effects).</div><div>Differ=
ent from a street machine where rust and grit take their toll in the rotor =
surface.</div><div>Phil Gott</div><div>114 TR4A <br> <br><div id=3D"ox-aa14=
149620-AppleMailSignature" dir=3D"ltr">Sent from my iPhone</div><div dir=3D=
"ltr"><br>On Jul 21, 2019, at 10:33 AM, ralph hansen via Fot &#60; <a href=
=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a>&#62; wrote: <br> <br>=
</div><blockquote type=3D"cite"><div dir=3D"ltr"><div class=3D"ox-aa1414962=
0-ydp941a9bf5yahoo-style-wrap" style=3D"font-family: Helvetica Neue,Helveti=
ca,Arial,sans-serif; font-size: 13px;">&#160;<br></div><div class=3D"ox-aa1=
4149620-ydp941a9bf5yahoo-style-wrap" style=3D"font-family: Helvetica Neue,H=
elvetica,Arial,sans-serif; font-size: 13px;">&#160;<br></div><div class=3D"=
ox-aa14149620-ydp941a9bf5yahoo-style-wrap" style=3D"font-family: Helvetica =
Neue,Helvetica,Arial,sans-serif; font-size: 13px;" dir=3D"ltr">not to rain =
on the parade but, are you turning the rotors each time to make sure they a=
re square also? if not, you now have unmatched surfaces - in the old days w=
ith good metal rotors I could see a slight advantage, these days with the g=
ood pads we get, and soft rotors they wear together, you might actually get=
 a very slight increase in surface contact due to the angles and dangles - =
and, as you machine the rotors you lose mass, the all important heat sink t=
hat makes brakes work....</div><div class=3D"ox-aa14149620-ydp941a9bf5yahoo=
-style-wrap" style=3D"font-family: Helvetica Neue,Helvetica,Arial,sans-seri=
f; font-size: 13px;"><br></div><div class=3D"ox-aa14149620-ydp941a9bf5yahoo=
-style-wrap" style=3D"font-family: Helvetica Neue,Helvetica,Arial,sans-seri=
f; font-size: 13px;">&#160;<br></div><div class=3D"ox-aa14149620-ydpfe57025=
dyahoo_quoted" id=3D"ox-aa14149620-ydpfe57025dyahoo_quoted_4630465933"><div=
 style=3D"font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font=
-size: 13px; color: #26282a;"><div>On Saturday, July 20, 2019, 07:19:46 PM =
CDT, Mathieu W. Huovinen via Fot &#60; <a href=3D"mailto:fot@autox.team.net=
">fot@autox.team.net</a>&#62; wrote:</div><div><br></div><div><br></div><di=
v><p>&#160;<br></p><p>Squaring up the pads? Please tell me more, I&#39;m st=
ill learning. Thanks!</p><p>-Marhieu</p><div class=3D"ox-aa14149620-ydpfe57=
025dyiv9411600540device_aol_et_org_dt_dd_quote">&#160;<br></div>___________=
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