Re: Proportioning Valves/ Brake Questions

["Rick Alexander" <rick@brubakerbox.com>]

Woops, way off center here. There are four outlets on our master cylinders
indeed. One piston with two chambers so that if a catastrophic failure were
to happen you could still stop. The problem with your assumption is that one
front and the opposite rear are on each chamber. This is to give the system
balance in the case of failure of one of the systems. You would still be
able to stop in a reasonably straight line. Now consider if you had the
fronts on one chamber and the rears on the other. If you broke a line at the
rear and lost all of your fluid you would be stopping on only the fronts
which will simply slide in a panic situation (longer stopping distance). Now
consider a break in the front hose, you would be stopping on the rears
only(a very considerable increase in stopping distance). Also consider that
brake lines fail only when you need them the most, a panic stop. You might
not have a problem as you would know what was going on, but suppose you had
lent the car to your Mother.

Adding flexible lines to a system would increase the mushy feeling in the
pedal as those lines expanded under their 10 to 15 thousand pounds of
pressure. This is why car manufacturers use the shortest flexible lines
possible. In fact they would love to be able to produce brakes that did not
use flexible lines. Any time you can avoid using flexible lines will keep
your pedal nice and hard. By the way, this is also the reason stainless
steel lines are used, so that the inner part can be Teflon which resists all
that pressure better giving a firmer feeling pedal.

Keep considering this stuff though as it is the best way to learn.

Rick Alexander
http://www.brubakerbox.com
http://clubs.hemmings.com/hams/
http://clubs.hemmings.com/vwsrus/

----- Original Message -----
From: "Brian Haygood" <Scirious@hotmail.com>
To: "Scirocco-l" <Scirocco-l@scirocco.org>; "Neal Tovsen"
<sixteen.volt@verizon.net>
Sent: Friday, November 09, 2001 12:55 PM
Subject: Proportioning Valves/ Brake Questions


> Neal, Randy and others;
>
> How do these Tilton proportioning valves work?  My understanding is that
> they use a spring, for which the preload is adjustable, to add a tiny
amount
> of squishyness to the rear brake lines, so that the front lines react a
bit
> faster to pedal travel.  It would be analogous to putting stainless lines
up
> front and leaving rubber lines in the rear, but in a finely tuneable way,
> thus giving you control over the ratio.  That about right?
>
> Neal, since our master cylinders, like most, have 4 lines coming out of
the
> MC, couldn't you just remove one of the rear lines from the MC, and put
one
> of these proportioning valves in the hole it leaves behind, and then split
> the remaining brake line somewhere along its path so that one line
services
> both rear brakes?  Unless I'm just misunderstanding the whole tandem
master
> cylinder thing, this should work, right?  If anybody can shoot me down, do
> it!
>
> If you wanted that proportioning valve inside the car, you could just run
a
> new piece of brake line up inside the car and mount the valve on it,
instead
> of mounting the valve directly onto the MC.  Using flexible line for this
> could be very convenient, depending on where you want your valve to end
up.
>
> Either this is a good idea, or I am way off base on all of it.
>
> -Brian
>
>
> ----- Original Message -----
> From: Neal Tovsen <sixteen.volt@verizon.net>
> To: 'Randy B' <sirocco@telocity.com>; <scirocco-l@scirocco.org>
> Sent: Friday, November 09, 2001 9:19 AM
> Subject: RE: Porsche 944T Master Cylinder on 81 Scirocco MS for 16V
brakes.
>
>
> > OOOhhh. That could be fun!
> >
> > Is there any way to have an adj. prop. valve on a standard MC? I've been
> > kinda wondering about that...
> >
> > Neal
> >
> > > -----Original Message-----
> > > From: owner-scirocco-l@scirocco.org
> > > [mailto:owner-scirocco-l@scirocco.org]On Behalf Of Randy B
> > > Sent: Friday, November 09, 2001 12:59 AM
> > > To: scirocco-l@scirocco.org
> > > Subject: Porsche 944T Master Cylinder on 81 Scirocco MS for
> > > 16V brakes.
> > >
> > >
> > >
> > > Ya'all been wondering why I am posting so often now????
> > > Ok, I have recently been laid off.
> > > Idle minds are the hands of......(How did this end?)
> > >
> > > Anyways while I've been lounging around watchin' soaps and
> > > CNN I have also
> > > been thinking about future mods. (once I get a job again that is).
> > >
> > > I have test fit a 944 Porsche Turbo MS to the stock 81
> > > Scirocco booster and
> > > it is a direct fit.
> > > This MS is 23mm for front and 20mm for rear.
> > > 2 line outputs for the front and 1 line output for the rear.
> > > I hope to run the single line through the firewall to the
> > > E-brake location
> > > and mount a Tilton adj. proportioning valve (one line in, two
> > > line out), and
> > > then run the dual lines back to the rear calipers.
> > > This MS compared to the 81 Scirocco MS which is 20mm for both.
> > > I am going to try this MS with my 16V brakes (currently running stock
> > > MS/Booster with 10.1/8.9 with pedal to the floor).
> > >
> > > I'll let ya'll know how this turns out in a future episode of
> > > the Young and
> > > the Restless......OOps, damn TV......
> > >
> > > Randy
> > >
> > >
> > > --
> > > Email LIST problems to: scirocco-l-probs@scirocco.org.
> > > To unsubscibe send "unsubscribe scirocco-l" in the message to
> > > majordomo@scirocco.org
> > >
> >
> >
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> >
> >
>
> --
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>




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