[DeTomaso] Caliper rebuild kits...
Steve Lisa
stevelisa at patentit.com
Mon May 21 12:34:16 EDT 2018
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>
*Scottsdale Office* | *P*: 480.535.6656 | *F:* 480.535.6628 | *A:* 7689
East Paradise Lane, Suite 2, Scottsdale, AZ 85260
*Chicago Office *|* P:* 312.752.4357 | *F:* 312.896.5633 | *A:* 55 E.
Monroe Street, Suite 3800, Chicago, IL 60603
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.
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,+Scottsdale,+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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-------------- next part --------------
All,A
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.A 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.A It was a SCCA "Majors Tour" National Event.A SN5533 has an
SCCA ITE logbook, which enables it to run in SCCA Vintage and Regional
events, but not in any SCCA National Class.A 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.A 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.A About 5
weeks ago I petitioned the SCCA to reinstate the Pantera in current
SCCA GT1 rules.A A
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.A
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.A 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.A So,A 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.A As it turns out the SCCA did not approve my
petition until Friday morning (test day).A 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.A 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.A 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.A We are running (per FIA GR3 rules)
stock 3 piston front calipers.A We pulled the calipers, saw the
o-rings in need of replacement.A After cleaning and reinstalling, we
kept blowing brake fluid past both front calipers.A We came up with
the concept of turning the square o-rings inside out and swapping the
two small piston locations in each caliper.A We did that on both
sides, and were able to bleed the brakes.A We missed the first
session, but went out for the second session to get some heat in the
calipers.A They held for the rest of the weekend.A Time for
rebuild.A By the way -- the calipers, pistons and cylinders were in
great shape -- thanks to Asa Jay maintenance.A 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.A We
built a new race motor for "other" (less snooty) events --A a Windsor
block (427, full race block from one of my other race cars) with
Cleveland Heads.A 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.A I estimate
we were running it around 450 HP and 450 ft lbs.A The motor was
absolutely a joy to drive, with a ton of torque and no worries about
cylinder wall thickness.A A
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.A 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.A We finally got it
done, and the car ran beautifully the rest of the day and that evening
for my son-in-law.A Our only problem the rest of the day/night was not
overheating the front brakes (we run 600 brake race fluid).A 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.A 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.A A
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.A It would not have been the slowest in the group, but
would have finished down in the order for sure.A 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 andA put it on real
slicks with light wheels, etc. etc. etc. it would be pretty fast!!A
But we have other race cars for that purposes, and this car is too
beautiful to start ripping it apart.A Right, now, it is street legal
with a license plate, power windows and an insurance card.
Thanks again for the great advice from everyone.A I will keep you
posted.A A A A
Regards,A
Steven G. Lisa, Esq.
Email: SteveLisa at PatentIt.com
Direct: 312-320-5888
[1][SGL-Email-Logo.jpg]
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
Chicago OfficeA |A P: 312.752.4357A |A F: 312.896.5633A |A A: 55 E.
Monroe Street, Suite 3800, Chicago, IL 60603
[2]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.
On Fri, May 18, 2018 at 12:51 PM, <[3]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 <[4]stevelisa at patentit.com>
To: List DeTomaso Forum <[5]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: [6]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 [7]7689 East Paradise Lane, Suite 2, Scottsdale, AZ 85260
Chicago OfficeA |A P:A 312.752.4357A |A A F:312.896.5633A |A A A:A
[8]55
[9]E. Monroe Street, Suite 3800, Chicago, IL 60603
[1][10]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. [11]http://www.PatentIt.com/
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