[DeTomaso] Caliper rebuild kits...

Mon May 21 14:26:29 EDT 2018

Steve,

Thanks for the interesting update. Quite an adventure!

I look forward to seeing 5533 next year when it is back from the West Coast.

Jim Kosloskey #6949

-----Original Message-----
From: DeTomaso [mailto:detomaso-bounces at server.detomasolist.com] On Behalf Of Steve Lisa
Sent: Monday, May 21, 2018 12:34 PM
To: List DeTomaso Forum <detomaso at server.detomasolist.com>
Subject: Re: [DeTomaso] Caliper rebuild kits...

All,

I wanted to say "thanks" for the unbelievably quick answers to my questions and advice on brake issues last weekend, and to Larry Stock for getting the rebuild kits to me by noon on Saturday.  I also wanted to give you all a quick rundown on how the weekend went for SN5533.

This weekend in Portland was not the usual SCCA Regional / Vintage weekend.  It was a SCCA "Majors Tour" National Event.  SN5533 has an SCCA ITE logbook, which enables it to run in SCCA Vintage and Regional events, but not in any SCCA National Class.  So a few months back I was looking at the rules and saw that a number of the old SCCA Trans Am, A and B Production race cars from the late 60's and early 70's were still listed as "approved" SCCA GT1 cars.  The Pantera was as well listed at one time in those classes (and the current SCCA Vintage rulebook), was no longer listed as eligible for current GT1.  About 5 weeks ago I petitioned the SCCA to reinstate the Pantera in current SCCA GT1 rules.

Now of course, we all know that the SCCA Trans Am and A and B Prod Pantera's were all very modified, akin to the FIA Group 4 mods.  SN5533 is in FIA Group 3 trim, and would get its ass kicked in that class, but it would enable it (and others) to race the Pantera at SCCA "National" or "Majors" events.  My thinking was there would always be someone to race with, and as it turns out, the GT1 class participation is dwindling due to cost.  So,  figured if I was in Portland to test the new motor, and if things went well in testing, I would do the SCCA National race and run towards the back of the pack with the GT3 and American Sedan cars.  As it turns out the SCCA did not approve my petition until Friday morning (test day).  Since we had a new fresh race motor built, I had already scheduled the test day for Friday (for me) and the Friday night track night for my son-in-law Dan.  But the crew was all leaving Friday night since we had not gotten SCCA approval to run the race before we showed up in Portland.  So we decided to run the nine sessions on Friday/Friday night, test and sort the new motor, and call it a weekend.

Friday morning I was greeted by brake pedals to floor and a puddle of fluid under the front right wheel.  We are running (per FIA GR3 rules) stock 3 piston front calipers.  We pulled the calipers, saw the o-rings in need of replacement.  After cleaning and reinstalling, we kept blowing brake fluid past *both* front calipers.  We came up with the concept of turning the square o-rings inside out and swapping the two small piston locations in each caliper.  We did that on both sides, and were able to bleed the brakes.  We missed the first session, but went out for the second session to get some heat in the calipers.  They held for the rest of the weekend.
Time for rebuild.  By the way -- the calipers, pistons and cylinders were in great shape -- thanks to Asa Jay maintenance.  We just needed knew seals.

The *original* motor for SN5533 has been safely rebuilt, dyno'd, packed and put away for posterity and for FIA GR3 "Gold Medallion" races.  We built a new race motor for "other" (less snooty) events --  a Windsor block (427, full race block from one of my other race cars) with Cleveland Heads.  That hybrid W/C motor dyno'd at 550 HP and 525 ft pounds of torque, which we dialed back with a smaller 600 carb and a lot of less timing so as to not blow up a the transaxle.  I estimate we were running it around 450 HP and
450 ft lbs.  The motor was absolutely a joy to drive, with a ton of torque and no worries about cylinder wall thickness.

However we had some transaxle isssues -- during the motor change before the weekend we had left the shift linkage attachment loose near the ZF input.
I managed to spin/mis-align the shift linkage in my first session, and we spent a lot of time and patience figuring out how to get a ZF and its shifter align it to work properly.  We finally got it done, and the car ran beautifully the rest of the day and that evening for my son-in-law.  Our only problem the rest of the day/night was not overheating the front brakes (we run 600 brake race fluid).  The car has a good head of steam at the end of the straights, and still weighs a lot, and FIA GR3 rules in '72 did not allow front bodywork mods for brake ducts.  Finding a place to pull air that is not "visible" from the front of the car is proving difficult. So the front brakes get overheated, which mandates a conservative amount of lifting and coasting into the corners at the end of the straights.

As for the SCCA National Races - we did not enter them, but we went back to watch and the Pantera would have been just fine racing in the GT1-GT3 group.  It would not have been the slowest in the group, but would have finished down in the order for sure.  It made me think -- gee, if I took out the second seat and glass, mounted some spoilers and lightweight body work, put real brake ducts on and  put it on real slicks with light wheels, etc. etc. etc. it would be pretty fast!!  But we have other race cars for that purposes, and this car is too beautiful to start ripping it apart.
Right, now, it is street legal with a license plate, power windows and an insurance card.

Thanks again for the great advice from everyone.  I will keep you posted.

Regards,

Steven G. Lisa, Esq.
Email: SteveLisa at PatentIt.com
Direct: 312-320-5888

<http://www.patentit.com>

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On Fri, May 18, 2018 at 12:51 PM, <jderyke at aol.com> wrote:

> Steve, cheap kits with new square sealing rings and boots are 
> available for both ends from all the Pantera vendors. But there's a 
> 50:50 chance that a kit will NOT fix the leakage either front or back. 
> The reason is, many Pantera owners simply refuse to do preventative maintenance on their cars.
> All British Girling calipers use nickel plated mild steel pistons (clue:
> OEMs are magnetic), so old water-soaked brake (and clutch) fluid rusts 
> them like a neglected bumper. Once the iron cylinders or steel pistons 
> are pitted, all is lost for cheap repairs. Honing the cylinders 
> oversizes the calipers for normal kits, which develop 1300 psi during hard braking.
> Adding a kit to pitted components will tear up the new seals almost 
> instantly. Girling no longer offers new pistons or cylinders and a 
> very few shops make such things. Porsche rebuilds their early piitted 
> pistons by chemically stripping the plating, welding up pits, grinding 
> back to size, plating with copper and polishing, then top-plating with chrome or nickel.
> Obviously, when reconditioned or billet pistons *are* found, they are 
> very expensive. Larry Stock reconditions OEM brake calipers but if 
> class rules allow, you'll be far ahead to upgrade to modern 
> lightweight aluminum calipers with stainless steel pistons, neither of 
> which will rust. Good
> luck- J DeRyke
>
>
> -----Original Message-----
> From: Steve Lisa <stevelisa at patentit.com>
> To: List DeTomaso Forum <detomaso at server.detomasolist.com>
> Sent: Fri, May 18, 2018 9:33 am
> Subject: [DeTomaso] Caliper rebuild kits...
>
> All, we are at PIR testing and sn5533 front calipers are leaking at 
> the piston seals.A We have no spare o-rings or rebuild. Are there any 
> common/close size o-rings that we can get an the auto part store that 
> will work in the '73 front calipers?
> Regards,A
> Steven G. Lisa, Esq.A
> Email: SteveLisa at PatentIt.comA
> Direct:A 312-320-5888
> Scottsdale OfficeA |A P:A 480.535.6656A |A A F:A 480.535.6628A
> |A A A:A 7689 East Paradise Lane, Suite 2, Scottsdale, AZ 85260
> <https://maps.google.com/?q=7689+East+Paradise+Lane,+Suite+2,+Scottsda
> le,+AZ+85260&entry=gmail&source=g>
> Chicago OfficeA |A P:A 312.752.4357A |A A F:312.896.5633A |A A A:A 55 
> <https://maps.google.com/?q=55+E.+Monroe+Street,+Suite+3800,+Chicago,+
> IL+60603&entry=gmail&source=g> E. Monroe Street, Suite 3800, Chicago, 
> IL 60603 
> <https://maps.google.com/?q=55+E.+Monroe+Street,+Suite+3800,+Chicago,+
> IL+60603&entry=gmail&source=g>
> [1]www.PatentIt.com
> This email is intended only for the recipient above, and may contain 
> confidential and privileged information. If you received this email in 
> error, please destroy it and indicate such by return email to me. 
> Thank you.
>
> References
>
> 1. http://www.PatentIt.com/
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