[DeTomaso] ABS Calipers vs. NON-ABS Calipers

Wed Jun 17 20:32:33 EDT 2009

Dear Chris,

            That sounds like a very nicely done brake project.   I have a question about it.  I have long appreciated the benefits of the absent brake vacuum booster.  I have also long wondered at how well the brakes feel and work without it.   The few people that have done the booster removal allege that it is a little different and requires a little more pedal effort.

             Have you tried driving and braking the car?   How did the brakes feel without the booster?

                          Very curious,  Chuck Engles

----- Original Message ----- 
From: "Chris Difani" <cdifani at pacbell.net>
To: "Ken Green" <kenn_green at yahoo.com>; <JDeRyke at aol.com>; <tborcich at msn.com>; <detomaso at realbig.com>; <MikeLDrew at aol.com>
Sent: Wednesday, June 17, 2009 7:01 PM
Subject: Re: [DeTomaso] ABS Calipers vs. NON-ABS Calipers

> Ken et al:
> 
> Yes, this is what I've done.  Used the Porsche-Brembo calipers, with 13" Coleman Racing rotors, with Wilwood hats, with the manual dual master cylinder from CNCbrakes:
> 
> http://www.cncbrakes.com/cncbrakes.com-asp//sra.asp?grp=sra&subgrp=d&series=240&subseries=Part 243 for Pantera bolt pattern
> 
> And the Airehart manual disc caliper adapter to the GT rear uprights, using the stock Pantera emergency brake actuation system.  I did something 
> somewhat-kinda-almost-but-not-quite-kinda-not-the-same as Jack on the mounting however.  My change was based on his experience with his "rattle".  I fixed things so that won't occur... for a very long time.  I also fabricated my "connection" to the Pantera e-brake cables based on what Jack did... hopefully making things a little bit better... but at the very least, not any worse.... 
> 
> My calipers came from a Porsche wrecking yard in the LA Basin, and cost me $125 each. Cash. In the hand. No receipt. Friday Night. 4:50PM. Last Guy In The Yard. Chain Link Gate 7/8 Closed. Broken English. Really Broken Spanish. The fact that I got very low mileage Brembo calipers that are specifically designed for severe road use was the reason that I did this type of conversion, rather than go with a package system.  I also did the 13" rotor change so I could remove the vacuum booster from the brake system, and from the front trunk.  You can not believe how much nicer the front trunk looks with a very small aluminum master cylinder, and with two braided stainless AN3 hoses disappearing thru bulkhead fittings into the floor. It's like night and day... plus I had already moved my battery back into the engine bay... on the passenger side.  
> 
> I will admit of the brake system entire process, the emergency brakes were the most problematic.  The Brembo's were very straightforward... except for one very minor detail...   The standard wheel studs have a step on them.  That "step" keeps the wheel from snugging up against the rotor and rest of the rotating assembly.  Without that "snugging up" thing, the "hat", rotor, wheel, etc., are NOT a single, solid, bolt-together-assembly.  That step is from .040" to .070" high, and that's the space you end up with.  It only takes a few minutes on a lathe to fix this problem, but it can take days to determine just what the heck is going on, and how to fix it.  
> 
> This problem is also not due to "wrong" wheel studs.  ALL wheel studs that are sold by the vendors have this "step" on them.  And when you make such a radical change, as I did, it becomes important... to say the least.  
> 
> If anyone has further questions, I've got pictures, etc., and will be glad to "share".
> 
> Chris
> 
> Chris Difani
> '73 L #5829 "LITNNG"
> The Electric Pantera
> Sacramento, CA
> Email: cdifani at pacbell.net 
> 
> 
> --------------------------------------------------------------------------------
> 
> 
> 
> ----- Original Message ----- 
> From: "Ken Green" <kenn_green at yahoo.com>
> To: <JDeRyke at aol.com>; <tborcich at msn.com>; <detomaso at realbig.com>; <MikeLDrew at aol.com>
> Sent: Wednesday, June 17, 2009 3:50 PM
> Subject: Re: [DeTomaso] ABS Calipers vs. NON-ABS Calipers
> 
> 
>> Parts and pads are one reason we have been working on an upgrade using Porsche 996 Turbo calipers. There are probably many more pads available, and these are not race pads and are made to last years, not minutes of track time. They are also designed for a car with a bit more weight and nearly identical weight distribution, so we are taking advantage of all the engineering Porsche did.
>> 
>> With all due respect, I doubt if any individual or vendor has even close to the development time Porsche and Brembo put into the specification, design and testing of these calipers on a car with very similar requirements, which is a nearly 200 MPH car. So while some adaptation is required, that is minor compared to selecting the right caliper to start with.
>> 
>> I can help anyone interested in this with finding the calipers, and part numbers for the correct hats and rotors. A local shop has made caliper brackets for $150, so all that's left is the master cylinder, and you probably can use the CNC Brakes bolt on dual MC. I think that's what Chris is using.
>> 
>> Ken
>> 
>> --- On Wed, 6/17/09, MikeLDrew at aol.com <MikeLDrew at aol.com> wrote:
>> 
>> 
>> From: MikeLDrew at aol.com <MikeLDrew at aol.com>
>> Subject: Re: [DeTomaso] ABS Calipers vs. NON-ABS Calipers
>> To: JDeRyke at aol.com, tborcich at msn.com, detomaso at realbig.com
>> Date: Wednesday, June 17, 2009, 1:52 PM
>> 
>> 
>> 
>> In a message dated 6/17/09 13 48 28, JDeRyke at aol.com writes:
>> 
>> 
>>> There are
>>> no known replacement pistons for most calipers
>>> 
>> 
>> Roland says he has them for the De Tomaso calipers; I would expect that the 
>> US vendors who overhaul brakes might have them too (although they are not 
>> listed as a separate part in the De Tomaso parts book).
>> 
>> Mike
>> 
>> 
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