Date: Sun, 01 Feb 1998 17:31:18 +0000
From: [email protected]
Subject: Re:  Re:  Brakes
To: Multiple recipients of list {[email protected]}

Panteras have a stock non-adjustable proportioning valve that is worse than 
useless. It is plumbed into your front brakes, limiting their effectiveness 
when it ought to be in the rear line to prevent rear wheel lock-up. #1- remove 
the stock valve & run with no valve, then decide if you really need an 
adjustable. If you do, Ford/SVO sells the Kelsey-Hayes screw-adjustable valve 
for about $50. Speed shops als carry it, and a Wilwood unit that is 
equivalent. Plumb it into the REAR brake line, not the front. J DeRyke 


Date: Thu, 12 Feb 1998 22:35:06 +0000
From: Kirby Schrader {[email protected]}
Subject: Re: Parking Brake
To: Multiple recipients of list {[email protected]}

}Like most of the list, my parking brake holds just long enough to stop,
}throw open the garage door, and get back in just before it rolls into the
}garage alone.  How about a little more of an explanation of you setup?

OK.... I started out with the stock setup and it didn't work. Well, it 
'worked', but it never held the car in place on even a mild grade. 

When I had the car rebuilt, I told Dennis that I wanted a brake that worked. 
He said the thing to do if I was putting on the Wilwoods was keep the original 
calipers on the rear and use them for the parking brake. 

Sounded good to me and it was better. But one day, I had to park on a grade 
and the car kept moving. OK, I got by with putting it in gear, but this wasn't 
right. Especially when I came back out and tried to release the lever that I'd 
pulled on so hard. I bent the lever and banged my elbow and got generally 
pissed off at that moment. 

Next time I was at PPC, I ranted to Dennis about it and the end result is that 
the old calipers are gone (less unsprung weight!) the cables are gone, the 
lever is gone, the bracket is gone... I think you get the idea. 

The area where the parking lever used to be is covered over with a plate and 
new carpet installed. A hole through the plate has a valve with a pointed 
lever on it that points straight ahead to go and a quick 90 degree turn to the 
right turns the valve on. The valve is inline with the rear brakes. 

So, you stand on the brake pedal, turn the valve to the right and the car 
stays where its put. Works great, easy to 'engage', no levers, etc. 

That answer your questions, George?

And just to try out the nifty digital camera, check the picture of the
lever at:
http://mwd.sugar-land.anadrill.slb.com:65080/zmisc/pantera/brakelever.jpg

That's the back of the passenger seat in the lower right, the idler pulley of 
the A/C compressor on the left. 

Or, the mess I've got in _my_ garage!
http://mwd.sugar-land.anadrill.slb.com:65080/zmisc/pantera/garage.jpg

http://mwd.sugar-land.anadrill.slb.com:65080/zmisc/pantera/carblock.jpg


Date: Sun, 15 Feb 1998 02:43:59 +0000
From: [email protected]
Subject: Re:  Re:  Re: Parking Brake - Reply
To: Multiple recipients of list {[email protected]}

A lot of how well the stock parking brake works has to do with the angle of 
the lower lever. I redid the bracket to make it removable and the lever angle 
changed a bit. The effectiveness went about to zero! I had to fiddle with the 
lever angle for a while to be able to hold the car on the flat! J DeRyke 


Date: Mon, 16 Feb 1998 00:31:29 +0000
From: [email protected]
Subject: Re:  Re: Parking Brake
To: Multiple recipients of list {[email protected]}

I think you're onto something, Andy. The way the 'retraction mechanism' on a 
disc brake caliper works is, they use a square-edge o-ring to seal the piston. 
Such an o-ring is not a particularly good hydraulic seal, by the way. The o-
ring is sized slightly smaller than one would normally use for a hydraulic 
seal, so the square-edge of the o-ring distorts a little under brake line 
pressure in its caliper groove, and the leading edge creeps down with the 
brake piston. When the pressure relaxes, the o-ring being rubber tries to 
resume it's former shape. When it does this, it tends to pull the brake piston 
(and pad) back away from the disc. This is the 'retraction mechanism' used in 
virtually all disc brakes. Prolonged hydraulic pressure could cause the o-ring 
to take a permanent 'set' in the distorted position, thus becoming a worse 
seal than it already is, and also not retracting the piston (and thus the 
brake pad). Overhaul time! The cable pull doesn't rely on the distortion of an 
o-ring for retraction, so it should be less damaging to the system. My guess 
is, using prolonged hydraulic pressure for a parking brake should lead to 
early rear brake trouble.  J DeRyke 


Date: Sun, 15 Feb 1998 23:51:29 +0000
From: [email protected]
Subject: Re:  Re: Parking Brake
To: Multiple recipients of list {[email protected]}

Hydraulic line-locks are fork-lift parking brakes, NOT emergency brakes. The 
law states that a separate system shall be provided for emergency use, in the 
event that a problem develops in the main brake system. Line-locks alone are 
not capable of causing a rolling car to even hesitate on its way to disaster. 


Date: Mon, 16 Feb 1998 01:09:39 +0000
From: Kirby Schrader {[email protected]}
Subject: Re:  Re: Parking Brake
To: Multiple recipients of list {[email protected]}

}I think you're onto something, Andy. The way the 'retraction mechanism' on a
}disc brake caliper works is, they use a square-edge o-ring to seal the piston.
}Such an o-ring is not a particularly good hydraulic seal, by the way.

Oooppsss!!!! I'd better tell all the mechanical guys to stop using those 
suckers downhole at 20,000psi and 175degC!!! 

Darn, Jack! Why do you say that? We use them all the time here in the oil
busines...

}brake piston. When the pressure relaxes, the o-ring being rubber tries to
}resume it's former shape. When it does this, it tends to pull the brake piston
}(and pad) back away from the disc. This is the 'retraction mechanism' used in
}virtually all disc brakes.

And piston presure compensation for us guys that use hydraulics downhole in
an oilwell. But, we do use a teflon backup ring.

} Prolonged hydraulic pressure could cause the o-ring
}to take a permanent 'set' in the distorted position, thus becoming a worse
}seal than it already is, and also not retracting the piston (and thus the
}brake pad).

Your point is taken.

}o-ring for retraction, so it should be less damaging to the system. My guess
}is, using prolonged hydraulic pressure for a parking brake should lead to
}early rear brake trouble.  J DeRyke

Hasn't yet, but then....

Sigh... You mean I should put that stupid handle back and pull a muscle
everytime I want to put the parking brake on?


Date: Mon, 02 Mar 1998 17:16:07 +0000
From: Mike Drew {[email protected]}
Subject: Re: Brake light switch; was Need to know sometime in 1999!
To: Multiple recipients of list {[email protected]}

In answering a question from someone else about their brake pedal coming too 
far back, I discovered that the Pantera has (or at least was suppose to have) 
a brake pedal stop bracket.  This stop bracket appears to be redundant in that 
the brake pedal height is controlled by the push rod adjustment and the stop 
bracket is to be adjusted with 3/32 to 1/8 inch CLEARANCE. 

}}}While working on my car last summer, I discovered this too.  This bracket 
is actually mounted on a pair of standoffs, but even so, mine is such that 
when it's fastened, it holds the pedal down about halfway, immobilizing the 
car!  And this is without the threaded adjuster even installed. 

Something is AFU for sure; When I first saw it I had thought of using this for 
a brake light switch as you suggested, but methinks it will require some 
malletizing first... :}) 


Date: Tue, 03 Mar 1998 01:09:16 +0000
From: JDeRyke {[email protected]}
Subject: Re:  Re:  Need to know now!
To: Multiple recipients of list {[email protected]}

When I first saw that 'shuttle valve" in our Panteras, it reminded me of what 
the military fighter mechanics call a 'hydraulic fuse'. When some unfriendly 
guy lobs a round through your airplane and cuts a line or hose, these things 
slam shut and stop the leakage. They're everywhere in the planes I'm familiar 
with. Aerospace high-tech in an old Pantera? Amazing! J DeRyke 


Date: Tue, 10 Feb 1998 20:50:26 +0000
From: [email protected]
Subject: Re: brake pad thickness
To: Multiple recipients of list {[email protected]}

Friction material thickness is 0.41" per measurement on set of NOS front 
DeTomaso/Girling pads.  Rears are about 0.38 when new.  This does not include 
backing plate. 


Date: Tue, 05 May 1998 17:51:45 +0000
From: JDeRyke {[email protected]}
Subject: Re:  Re: Brakes/parking brakes
To: Multiple recipients of list {[email protected]}

{{I have to wonder about the wisdom/utility of a 0.75" thick vented rotor.
  Seems to me there ain't room in 3/4" for both thick friction surfaces and 
  wide air passages.  Seems like they'd either be prone to warping (thin 
  surfaces) or not be very effectively vented.  I could be wrong though - lord 
  knows it's happened a few times.}} 

Andy, the thing that sorta started this whole thread was, 8 years back my use
of early Porsche 911 ventillated discs on both ends of our Pantera. The rotors
are vented, and the same dia & thickness as the stock Pantera. There sure are
enough fast old 911s around and they have little trouble with their 0.75 thick
discs warping. You gotta fabricate hat sections to mount them on a Pantera hub
but they've worked out well for me. And based on my exercise, Tomas Gunnarson
in Sweden adapted Turbo-Volvo 850 front & rear vented rotors to his Pantera
(not many wrecked Porsches in Sweden, he says) You musta missed both articles
in past POCA newsletters. I think WPK (a list member) in Texas is also running
911 rotors in front on his lime-green Pantera.

J DeRyke (now working on parking brakes discarding the stock rear calipers)


Date: Fri, 08 May 1998 14:21:18 +0000
From: Mike Drew {[email protected]}
Subject: Re: PPC brakes pictures
To: Multiple recipients of list {[email protected]}

I've got this system on my car.  One HIGHLY ANNOYING aspect of it is the
fact that the ports on the master cylinder exit on the right.  Hall
Pantera's ports are on the left.  With the Quella system, your brake
lines are left dangerously vulnerable to damage from any heavy items in
your trunk.  You go hauling ass around a hard right turn with a heavy
tool box in the front trunk, it shifts sideways due to the lateral loads
and smacks right into your brake lines, which could cause leaks, and
maybe even failure?  Bad design.

Hall's runs on the other side, and while it can be a pain in the butt
'cause the clearances are tight, ultimately it's a much better idea in
my view.  It looks to me that they both bolt up to the booster in
exactly the same way; they're probably interchangable (of course, you'll
have to dink with the hard lines...)

Also, check the photo of the master cylinder and note the blue dealybops
underneath the master cylinder (in the brake lines.)  These are one-way
check valves.  When these racing brake systems were first being offered
on the market, they offered outstanding ultimate performance but AWFUL
pedal feel.  I drove Jim Firanzi's car (then owned by Marcus Smith)
which had Hall's JFZ system on it, and it was almost undriveable to me,
because one minute you'd step on the brakes and have a rock-hard pedal,
then later you'd step on the brakes and the pedal would go through three
inches of mush, and then suddenly become rock hard.  Either way the car
would stop, but it was difficult to know how much to modulate the pedal.
It was easy to either bounce your face off the steering wheel, or scream
up to partially through a stop sign, depending on how the car felt like
reacting.

What was happening is this:  The racing brake system has a total of 16
pistons, and as you drive down the road, the discs would cause the pads
to vibrate, and the pads/pistons would slowly migrate away from the
discs.  Thus the first time you step on the pedal after several minutes
of driving, the initial pedal travel would be used to push all 16
pistons back out of the calipers until the pads were actually touching
the disc; THEN you'd get a solid pedal (and braking action.)

These check valves solve this problem.  They are something like 4 psi valves; 
they allow fluid to flow unrestricted TO the calipers, but hold 4 psi pressure 
against the calipers so the fluid doesn't flow back out. This isn't enough 
pressure to cause any braking action, but it IS enough to keep the 
pistons/pads where they're supposed to be, so you get instant braking reaction 
each time you step on the pedal, time after time. 

These suckers are made by Wilwood, and are fairly inexpensive.  If you've got 
a racing brake setup and have this problem, here's your solution. 

(Note:  The vendors now include these valves as a standard feature of
their racing brake packages.)

Race cars can get away with not running them because they are on the brakes so 
often that the pads don't have time to migrate away from the disc. 

Why don't regular production cars have this problem, and this solution?


Date: Sat, 09 May 1998 01:06:48 +0000
From: JDeRyke {[email protected]}
Subject: Re:  Re: Offset bushings
To: Multiple recipients of list {[email protected]}

Andy, if your rotor-to-a-arm clearance is that close, why not simply shim the
wheel bearings outboard like 0.050" or so? A hardened washer between the
spindle & inboard bearing is all that's necessary. Worked for me... just don't
go overboard so the nut has no threads to hang onto. J DeRyke


Date: Tue, 26 May 1998 20:18:50 +0000
From: RLG1973L {[email protected]}
Subject: Re: REAR Brakes:interchange
To: Multiple recipients of list {[email protected]}

A direct replacement for the Pantera rear pad is made by Hawk Brake.  Their 
part number is HB175.  Several pad materials are available.  Hawk is a popular 
race pad, but they have street materials, too.  They have a web site with all 
pads pictured.  I believe it's www.hawkbrake.com.  I recommend to our vendors 
that they stock these. 


Date: Wed, 27 May 1998 12:53:59 +0000
From: Ted M {[email protected]}
Subject: Re: REAR Brakes:interchange
To: Multiple recipients of list {[email protected]}

The parts interchange list indicates part no. D105 as the correct one for
the Pantera.


Date: Thu, 18 Jun 1998 13:49:40 +0000
From: [email protected]
Subject: Re:  single/double brake line flare ?
To: Multiple recipients of list {[email protected]}

{{Anyone have strong views on the necessity for a double flare in brake line 
  ends ? -W}} 

William, double-flaring hard lines is mandantory IF you use std steel brake
line, which is also known as "Bundyweld". Bundyweld is rolled sheet steel that
is furnace- brazed together to make a tube; single-flaring will almost always
split it at the braze line, causing a leak. Double flared bundyweld does not
split. This by the way is '30s technology that was never updated. Conversely,
it is almost impossible to double-flare stainless steel tube because of the
instant work-hardening it does. So for SS, I think single flare is OK- we used
single flares on ss tubing in Lockheed's spacecraft w/no problems. And
remember, bundyweld is the only "official" DOT-certified hard line except for
Pat Mical's Future Auto ss hard lines. Don't know which flare Pat uses. J
DeRyke


Date: Tue, 18 Aug 1998 18:55:53 +0000
From: Cristiano Rossi {[email protected]}
Subject: Sv: Master Cyl.
To: Multiple recipients of list {[email protected]}

I have now found the note with the price of the vacuum booster/master cylinder 
assembly that I got from the De Tomaso spareparts-man at the beginning of july 
1998. 

The parts number is 51042034, and the price is (without italian VAT of 20
%) Lit. 440.000,-. I was exaggerating a little when I told you the price
was about 200,- $, in fact I think that Lit. 440.000 is closer to 250,- $,
but you can make the calculation yourself. The italian VAT shall not be
paid if the parts are exported.

It is the same kind of booster and master cylinder that was originally
mounted on our cars, and the parts are naturally brand new.

The De Tomaso factory does in fact in most cases have very reasonable and
competitive prices, and I think that also for you americans it could
sometimes be an advantage to import yourself certain spares directly from
the factory, although there would also be a cost of transportation.

The master cylinders are _not_ "unobtanium", the factory has almost all
spares imaginable for the Panteras. Only few items can not be found. I have
never ordered anything yet that the factory could not deliver.

Cristiano Rossi
thpnma 02869

P.S. I don't know if the factory has seal kits.


Date: Mon, 15 Jun 1998 20:56:16 +0000
From: "Charles F Engles Jr." {[email protected]}
Subject: Brakes and Tornadoes
To: Multiple recipients of list {[email protected]}

The Pantera Research Institute here is untouched after the tornado attack
yesterday and will continue its sporadic work and questionable studies
without any evident interruption.  All is well.

In follow up about my overheated rear brakes at the track, I got another 
chance to run at the track last week and work on the brakes.   Apparently, 
after the brakes were debugged by Kip Partridge at PPC the car was then 
afflicted in short order by a frozen caliper piston and a slow leak in one of 
the tires.  While this was going on, I monkeyed with the dual master cylinder 
balance bar and accidentally put too much on the rear brakes. Then, last 
month, I discovered that the rear brakes were running way too hot. 

Last week, using the infrared noncontact thermometer and the
seat-of-the-pants, I slowly put more bias on the front.  The braking was
steadily better with each track session.  The temperature readings slowly
came down on the rear rotors and came up on the front rotors.
By the last session, the brakes were excellent and the front rotors were
running 400 degrees F. and the rears 410-415 degrees.  My buddy's NSX runs
450 front and 350 rear, so I am clearly in the right ballpark.  Also, I
think it shows that there is not a great need for ducting to cool the
overheated rear brakes because the heat was due to excessive rear brake
bias.  Also there doesn't seem to be a big difference at present in the
"heat capacity" (?) of the vented vs the solid rotor in the situation at
Hallett.  Also, when the rotors are at 400 degrees the Wilwood Superlite II
calipers are only about 200degrees, which still gives the fresh brake fluid
plenty of safety margin before boiling.

My plans are to continue to tweak the bias when I get back to the track in
October and shoot for slightly warmer front than rear rotors.


Date: Tue, 13 Oct 1998 14:59:48 +0000
From: [email protected]
Subject: Re:  Finally took possesion...
To: Multiple recipients of list {[email protected]}

{{The first is about the master cylinder.  It is standard ford, where do I get 
  a rebuild kit for it.  I don't want to change it, just rebuild it. 

Sorry, Landis- the OEM master cylinder was a Bonaldi or a Girling-made-in-
Italy-under license; if you have a Ford cylinder, its already been changed.
Kits are available for Fords as long as you know what it came off of; none
exist for the OEMs (that are effective) but new stock cylinders are available
from the usual suppliers.

Second is the windows travel very slowly.  Is there a way to rebuilt the
motors for the windows to make them faster.

The windows bind up as the rubber channel guides get old & debond. Replace the
channel liners & adjust the metal channels as req'd for smooth window travel.
And as long as you're in there, you definitely need a brass drive gear in the
window motor. Stock was a plastic gear that WILL break, freezing the window at
whatever position it was. Gary Hall, Wilkinson etc all stock them. Check the
window motor brushes, too- they're Ducellier from France. Might be able to
match up brushes from something else.

The radiator fans are hooked up to run full tome. How do I go about installing
a thermostat and relay to make them go on only when neccessary. }}

The stock radiator has 2 thermostats built into the lower header tank. The
stock thermostats often malfunction, which is probably why the fans are wired
as they are now. The thermostats can be replaced at great cost & effort from
the usual suppliers, IF you still have a stock radiator. Lots of aftermarket
units do not have built-in thermostats. The wiring should all still be there-
the relays are facing the radiator, left side of the front trunk near the
headlight bar. Good luck- J DeRyke