[DeTomaso] Brake master plumbing
Julian Kift
julian_kift at hotmail.com
Wed Jul 20 10:19:20 EDT 2022
Correct, however the step bore (or more correctly quick take up) master cylinder provides a means to get a large volume of fluid to the calipers upon initial braking to take up the gap between rotor and pad. This was a GM truck design to implement low drag pads to meet fuel economy thresholds, the pads sitting further away from the rotor. The larger bore is a small section on the master cylinder to effect that initial take up, it is not a dual bore with independent proportioniong function for front and rear circuits.
Julian
________________________________
From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of Will Kooiman <will.kooiman at gmail.com>
Sent: Wednesday, July 20, 2022 4:20 AM
To: Asa Jay Laughton <asajay at asajay.com>; detomaso at server.detomasolist.com <detomaso at server.detomasolist.com>
Subject: Re: [DeTomaso] Brake master plumbing
I would think you're correct - larger rear outlet 1-3/8" goes to the front, smaller front outlet 7/8" goes to the rear.
The front 6-piston has more surface area on the pads, so it needs a bigger bore on the master.
But if it's all together, how does it drive? Is the proportioning about right? Is there an external proportioning valve that might be fixing the mismatch?
On 7/20/22, 1:42 AM, "DeTomaso on behalf of Asa Jay Laughton via DeTomaso" <detomaso-bounces at server.detomasolist.com on behalf of detomaso at server.detomasolist.com> wrote:
Hi all,
This brake master cylinder is installed in a Pantera with Wilwood
six-piston brakes front and rear:
The master has a stepped bore. The larger at the rear measures 1-3/8"
and the front bore is smaller (probably 7/8" or an inch; I forgot to
measure). The question is, which port on this master is supposed to go
to the front brakes?
In my experience, most brake master cylinders of this type have the
larger reservoir going to the front brakes, and the smaller to the
rear. In my experience most masters of this type have the front brakes
plumbed to the rear outlet (meaning the outlet closest to the pedal
with the larger reservoir).
Since this is a non-stock installation, and I know some variations can
mean the front brakes plumb to the front, I am curious which port on
this master should go to which end of the car. I question this because
I did not find this plumbed the way I expected, and maybe that is fine.
This particular system may have been originally installed by Bobby
Byars, who is unfortunately no longer available for consultation.
I thank you in advance for your thoughts on this.
Thank you,
Asa Jay
--
Asa Jay Laughton - W7TSC, MSgt, USAFR, Retired
Spokane County ARES-RACES-ACS EC/RO
******************************
[1]https://w7tsc.org
[2]https://www.teampanteraracing.com
References
1. https://w7tsc.org/
2. https://www.teampanteraracing.com/
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-------------- next part --------------
Correct, however the step bore (or more correctly quick take up) master
cylinder provides a means to get a large volume of fluid to the
calipers upon initial braking to take up the gap between rotor and pad.
This was a GM truck design to implement low drag pads to meet fuel
economy thresholds, the pads sitting further away from the rotor. The
larger bore is a small section on the master cylinder to effect that
initial take up, it is not a dual bore with independent proportioniong
function for front and rear circuits.
Julian
__________________________________________________________________
From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of
Will Kooiman <will.kooiman at gmail.com>
Sent: Wednesday, July 20, 2022 4:20 AM
To: Asa Jay Laughton <asajay at asajay.com>;
detomaso at server.detomasolist.com <detomaso at server.detomasolist.com>
Subject: Re: [DeTomaso] Brake master plumbing
I would think you're correct - larger rear outlet 1-3/8" goes to the
front, smaller front outlet 7/8" goes to the rear.
The front 6-piston has more surface area on the pads, so it needs a
bigger bore on the master.
But if it's all together, how does it drive? Is the proportioning
about right? Is there an external proportioning valve that might be
fixing the mismatch?
On 7/20/22, 1:42 AM, "DeTomaso on behalf of Asa Jay Laughton via
DeTomaso" <detomaso-bounces at server.detomasolist.com on behalf of
detomaso at server.detomasolist.com> wrote:
Hi all,
This brake master cylinder is installed in a Pantera with
Wilwood
six-piston brakes front and rear:
The master has a stepped bore. The larger at the rear measures
1-3/8"
and the front bore is smaller (probably 7/8" or an inch; I
forgot to
measure). The question is, which port on this master is
supposed to go
to the front brakes?
In my experience, most brake master cylinders of this type have
the
larger reservoir going to the front brakes, and the smaller to
the
rear. In my experience most masters of this type have the front
brakes
plumbed to the rear outlet (meaning the outlet closest to the
pedal
with the larger reservoir).
Since this is a non-stock installation, and I know some
variations can
mean the front brakes plumb to the front, I am curious which
port on
this master should go to which end of the car. I question this
because
I did not find this plumbed the way I expected, and maybe that
is fine.
This particular system may have been originally installed by
Bobby
Byars, who is unfortunately no longer available for
consultation.
I thank you in advance for your thoughts on this.
Thank you,
Asa Jay
--
Asa Jay Laughton - W7TSC, MSgt, USAFR, Retired
Spokane County ARES-RACES-ACS EC/RO
******************************
[1]https://w7tsc.org
[2]https://www.teampanteraracing.com
References
1. [1]https://w7tsc.org/
2. [2]https://www.teampanteraracing.com/
_______________________________________________
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Detomaso Email List is not managed by POCA
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use the links above.
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message posted here to all past, current, or future members of the
list. They also grant the list owner permission to maintain an archive
or approve the archiving of list messages.
References
1. https://w7tsc.org/
2. https://www.teampanteraracing.com/
3. http://server.detomasolist.com/mailman/listinfo/detomaso
4. http://server.detomasolist.com/mailman/listinfo/detomaso
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