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Re: [oletrucks] master cylinders

To: oletrucks@autox.team.net
Subject: Re: [oletrucks] master cylinders
From: jelerath@us.ibm.com
Date: Mon, 8 May 2000 15:04:24 -0600

I have a disk/drum master cylinder in a F*&d in which the front reservoir
is smaller than the rear, but the front reservoir is connected to the rear
(drum) brakes.

In Chevy products (Camaro proportioning valves) the "proportioning valve"
also has a restrictor built in internally.  I think that will dominate in
the flow restrictions over the line diameter.  My logic says if the line
diameter were critical, we'd have to make sure that each brake line, to the
left and right side, is exactly the same length....they aren't.


Jon Elerath
'53 3100 (Camaro, Bel Air, Chevelle, Chrysler, etc, etc)
Cupertino CA


"ROGER GLEASON" <rogerg@maverick.facil.uconn.edu>@autox.team.net on
05/08/2000 05:29:42 AM

Please respond to "ROGER GLEASON" <rogerg@maverick.facil.uconn.edu>

Sent by:  owner-oletrucks@autox.team.net

To:   oletrucks@autox.team.net
Subject:  Re: [oletrucks] master cylinders

I'm not an expert but i still disagree ... The front plunger chamber
in the master cylinder on a disc/drum system is smaller than the
rear, the front lines are also smaller... This will restrict the flow
to the front wheel cylinders... When the rear brakes fill up faster
than the front they are going to lock up causing you to spin
out... It will take a long time to fill up the front cylinders
because these cylinders are usually larger than the rears... When you
push on the brake pedal the rear chamber will fill the rear cylinders
first and thus stop the master cylinder plunger from going any
further thus causing the proportioning valve to move but it can only
move so far and has its own limiting capacity. If you guys that have
made this exchange can get your front wheels to lockup before the
back ones do then I stand corrected but if it was me I would exchange
a drum/drum master cylinder to replace the old single line type, and
I would stay away from those designed to work with disc/drum ones.

> From:          "joe" <chevy1@jps.net>
> To:            "ROGER GLEASON" <rogerg@maverick.facil.uconn.edu>
> Cc:            <oletrucks@autox.team.net>
> Subject:       Re: [oletrucks] master cylinders
> Date:          Mon, 8 May 2000 07:14:47 -0700
> Reply-to:      "joe" <chevy1@jps.net>

> You can still use the disc/drum master cylinder on a drum/drum system but
> that's where the proportioning valves and the added residual pressure
> comes into play.  The added residual pressure valves takes over for the
> added pressure needed for the drums 10 lb (disc uses a 2 lb valve).
> The proportioning valve then fine tunes the braking system for the weight
> characteristics of the truck to make sure all brakes apply evenly.
> You could just buy a drum/drum master cylinder but your still going to
> the proportioning valve.
> Joe Garcia
> 1950 Chevrolet 3100
> 1950 Willys Jeepster
> Yuba City, Ca
> http://chevy1.freeservers.com/
> http://jeepster.freeservers.com/
> http://50chevy.freeservers.com/
> ----- Original Message -----
> From: ROGER GLEASON <rogerg@maverick.facil.uconn.edu>
> To: <oletrucks@autox.team.net>
> Sent: Monday, May 08, 2000 6:36 AM
> Subject: Re: [oletrucks] master cylinders
> > I don't think you can use the master cylinder from a front disc rear
> > drum brake system on a 4 wheel brake system due to the different line
> > sizes being that they use small lines for the front and large for the
> > rear... The system was designed for use with disc on front and the
> > fluid needed to push the calipers closed is much less than the amount
> > needed for the rear drums.. You need a master cylinder for a drum
> > front drum rear.
> > rogerg
> >
> >
> >
> > > From:          "Brian m" <pkupman57@hotmail.com>
> > > To:            Passnb4U@aol.com, oletrucks@autox.team.net
> > > Subject:       Re: [oletrucks] master cylinders
> > > Date:          Sat, 06 May 2000 14:25:25 PDT
> > > Reply-to:      "Brian m" <pkupman57@hotmail.com>
> >
> > > hi all
> > > well, i went to pick-in-pulls half off day today. got a power
> pedal
> > > assy. and master cylinder from an 85 camaro. but becuase the M/C is
> such
> > > an angle, i also got a M/C from a 77 firebird. both have
> > > valves (are they needed if im useing 4 drums?) ive held it all in
> and
> > > from the way it looks, it should fit perfectly. the pedal hangs to
> > > where the stock pedal is (but a lil more to the left, as the arm is
> the
> > > left side of the colume) and the booster and M/C line up nice on the
> engine
> > > side, the lower left hand bolt on the dash support looks like it will
> > > used to hold one of 4 courners of the M/C and pedals up. is this a
> > > idea? what about this plate on the motor side? welding it up is no
> problem,
> > > as i have access to welders. but id rather not weld if i dont have
> also,
> > > i got a brake light switch that works mechanically, and it has 4
> in
> > > it, im assuming 2 are for the brake lights, and 2 are for cruise
> control,
> > > but which is which, all i remember of the colors are that one swtich
> blue
> > > and orange, and the other two are some other colors i forget.
> > > thanks,
> > > Brian
> > > Atwater, CA
> > > '57 chevy 3200
> > >
> > > oletrucks is devoted to Chevy and GM trucks built between 1941 and
> > >
> > Rogerg
> > 51-3100 AD Huckster
> > Lisbon, Connecticut
> > oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
> >
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
51-3100 AD Huckster
Lisbon, Connecticut
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

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