DeTomaso Mailing List: December 99, Message #118

My experience with the stock system is that it seems to work fine for its
design.  One of the things advocated back in the early 70's to get more overall
braking effort from stock, was to defeat the "Americanizing" measures imparted
to keep 'Mericans [accustomed to lead sled front engined detroit iron] from
spinning out with a low polar moment of inertia car.  The master cylinder has a
little acorn nut that screws in and out and couples with the power brake
diaphragm.  To screw it out causes the master cylinder pistons to be pushed
further into the master cylinder bore, increasing brake line pressure etc,etc.
Thus adjusted, the brakes lock, front first, rears when braking on an undulating
surface etc.  If screwed too far the brakes won't release.
The reason stated for de-tuning the brakes was if a wheel on our mid engine cars
has more traction than another, the wheel with the most traction [especially the
fronts] can whip the car on its axis, .  In competition driving we have to toss
the car taking advantage of its mid engine design.  It may be that I've
acclimated to the reduced effort of the rear brakes, but locking rears sounds a
little scary to me.  Maybe I haven't driven fast enough.
TW
#2821
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hopp@concentric.net wrote:

> I would like to provide some experience to the stock pantera brake system.
> I am not a brake authority but spent some time messing around with mine when
> I didn't want to change too far from original.
> This is what I learned.
>
>  The master and rubber hoses to me are a no brainer- change them.  What I
> did after that was remove the restrictor valve that reduces the pressure to
> the front brakes.  When I did this the front brakes would actually lock up
> before the rears.  Next I had access to a pair of rear factory calipers and
> added an additional set to the rear and plumbed them into the brake lines.
> Then the rears would lock up first before the fronts.   Then I added a
> proportioning valve to the rear brakes to reduce the force on the dual
> calipers and adjusted the valve until the frontand rear balanced.
>
> Now the result is my brakes are far supperior to original and would
> describe them as reasonably good. They seem to be strong with no fade on the
> street.  On the other hand I am not advocating doing this in place of a
> vender system.   I now would like a stage 2 system or better.   The real
> reason I provided this info is because it may help to understand more about
> the stock system and might give you some insights to things you might be
> considering doing.
> Rich Hoppe
> ----- Original Message -----
> From: Jones, Daniel C <Daniel.Jones@MW.Boeing.com>
> To: Multiple recipients of list <detomaso@realbig.com>
> Sent: Wednesday, December 08, 1999 1:30 PM
> Subject: RE: Re[2]: Suggestions on brakes???
>
> > You'll have to explain why that is so.  Under braking, the majority
> > of deceleration comes from the front brakes.  When the limiter kicks
> > in, my rears lock momentarily, increasing braking distance.  All of
> > the other cars that I've driven have proportioning valves which reduce
> > pressure to the rear brakes after a certain pressure is reached.
> >
> > Dan Jones
> >
> > > If the pop-off valve you refer to is the front circuit pressure
> > > limiter I can tell you that removing a functional limiter from a stock
> > > system is a sure way of increasing, not improving, the brake distance.
> > >
> > > Tomas
> > >
> >
> >