[DeTomaso] Trying to diagnose weak brakes

Charles G. Zaroulis charles.zaroulis at gmail.com
Sat Feb 17 15:19:12 EST 2018


Is there a kit for a blind spot indicator?


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from CHARLES G. ZAROULIS, M. D. that is confidential or privileged. The information is intended to be for the use of the individual or entity named above. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this information is prohibited. If you have received this email in error, please notify the sender immediately by reply email and destroy all copies of the original email. Thank you very much.

On Feb 17, 2018, at 2:37 PM, Mike Drew via DeTomaso <detomaso at server.detomasolist.com> wrote:

Mike,

In answer to your last question:

Yes, you are nuts. I think your car was great when I rode in it ten years ago or so and it has only gotten better over time, I think. If it was a POS then tearing it apart might be justified, but it’s not, so it’s not. 

Drive it and enjoy it!  :)

We all know people who started with perfectly good cars and ‘improved’ them to the point of complete immobility.  It takes rather a lot of the fun out of it.....

Mike

Sent from my iPad

> On Feb 17, 2018, at 11:33, Mike & Elizabeth Thomas <mbefthomas at comcast.net> wrote:
> 
>  Not really.  Since I replaced my master some years ago, the brakes have
>  never been what I would call `stellar', and starting just such a thread
>  to get them figured out has been on my mind, but more pressing fixes
>  were needed.  Now that the rest of the car is running better then it
>  ever has, this is at the top of the list.
> 
> 
>  `Course, doesn't it make sense that after years of tinkering this and
>  that, everything seems to be coming together just as I'm contemplating
>  a full tear down for a restoration of the metal/paint.  Am I nuts . .
>  .  ?
> 
> 
>  Thanks
> 
>  Mike T.
> 
> 
>  From: Jeff Cobb [mailto:jeffcobb1 at me.com]
>  Sent: Saturday, February 17, 2018 11:03 AM
>  To: Mike & Elizabeth Thomas <mbefthomas at comcast.net>;
>  DeTomaso at server.detomasolist.com DeTomaso at server.detomasolist.com
>  <detomaso at server.detomasolist.com>
>  Cc: Jeff Cobb <jeffcobb1 at me.com>
>  Subject: Re: [DeTomaso] Trying to diagnose weak brakes
> 
> 
>  Mike,
> 
>  Something strikes me as being out of order in the problem-cause and
>  effect diagnosis of understanding and fixing your brake pedal travel
>  problem in reading these back and forth mails. You write as if these
>  problems just appeared.
> 
> 
>  Seems that your real stated problem is;
> 
>  -1-perceived or really too much pedal travel.
> 
>  -2-cannot lock up wheels
> 
>  Also:
> 
>  -1-more brake dust on rear wheels versus the fronts.
> 
> 
>  My questions are simple.
> 
>  -1-When this problem start?
> 
>  Not when you first noticed or recognized it, but when it first showed
>  up.
> 
>  -2-Was this first time problem right after someone worked on it?
> 
>  -3-Has someone done any adjusting to the pedal unit?
> 
> 
>  My brake work fixing history has taught me:
> 
>  --Your #1 and 2 make sense.
> 
>  --This type of problem #1 and #2 does not just show up
> 
>  --Also more rear dust than fronts indicates a brake bias imbalance.
> 
>    NEVER do rears have more dust than fronts on any car because of
>  laminar air flow.
> 
>    The fronts always run hotter which   emits more gas and powder.
> 
>  --That GM masters NEVER give a tight brake pedal unless they are p/s
>  pumped hydraulic boosted power brake function or
> 
>  using a vacuum booster with an electric motor vacuum pump.
> 
>    The vacuum should be between 16 to 21.
> 
>  My thoughts to cure your two stated problems.
> 
>  -1-Make sure the brake pedal to booster pushrod does not have any slack
>  caused by wear and giving sloppy joints,
> 
>    That the first pushrod is set correctly so that the pedal is correct
>  height from floor.
> 
>    the vacuum booster pushrod to master does not have too much
>  clearance--Should be about .020".
> 
>  -2-Then bled your brakes in the correct order; RR-LR-RF-LF.
> 
>    while watching for air bubbles and any type of pad to rotor air
>  clearances/movement so to give reasons.
> 
>    If doing above work makes no difference "which I would be surprised".
> 
> 
>  -3- then you need to plug off the master outputs and see if master
>  travel is non and rock hard.
> 
>   When all above is correct and still note problems then you problem is
>  in the fluid/caliper/pad space.
> 
> 
>  -4-If you had rubber lines you could pinch them off with vise grips and
>  find the soft one.
> 
>    Since you do not then a temp gun and some hard 60mph stops will give
>  you your temp rise to grip performance function.
> 
>    Do 3 stops then measure/record then do 6 or so more and read and
>  write again.
> 
>    Axle temps should be same and fronts are always more.
> 
>    The lowest temp unit will be your problem.
> 
> 
>  Thoughts:
> 
>  -1-I have had brake problems caused by owners spraying tire shine shit
>  on their wheels. That crap coats and greases the rotors which then
>  kills the pads from gripping.
> 
>  -2-Also calipers with rubber piston boots that retract the pads more
>  than .002" will cause problems.
> 
>  -3-Also if the rotors are not dead center to caliper then weird stuff
>  lives on. Calipers can be shimmed to center them.
> 
>     Jaguar did that on all of their XJS v12 cars and when I recently
>  removed my Mangustas L rear caliper, mounting shims were present. Which
>  was it first ever removal, so the factory did the shims because of
>  manufacturing differences.
> 
> 
>  If none of this allows the car to stop better then maybe your pads
>  function temp range is not right for you.
> 
>   Take care,
> 
>  Jeff Cobb
> 
> 
>  On Feb 17, 2018, at 10:45 AM, Mike & Elizabeth Thomas
>  <[1]mbefthomas at comcast.net> wrote:
> 
>      Thanks all.  I am planning a full-on restoration of the car in a
>    year
>      or two, and running of fresh brake lines, master, etc. even if I
>    do
>      retain the original Girling brakes, will be on the list.  I will
>    try a
>      proper bleeding, and it may not be a bad idea to upgrade to
>    whatever
>      master I intend to use after the restoration.  I may consider
>    going the
>      full Willwood route, but as I never intend to track the car, that
>    may
>      be overkill.  If I stay with the Girling calipers, I'll certainly
>    have
>      them properly rebuilt.
>      Mike Thomas
>      From: Julian Kift [[2]mailto:julian_kift at hotmail.com]
>      Sent: Saturday, February 17, 2018 8:20 AM
>      To: Joseph F. Byrd, Jr. <[3]byrdjf at embarqmail.com>; 'Mike &
>    Elizabeth
>      Thomas' <[4]mbefthomas at comcast.net>; 'List DeTomaso Forum'
>      <[5]detomaso at server.detomasolist.com>
>      Cc: 'List DeTomaso Forum' <[6]detomaso at server.detomasolist.com>
>      Subject: Re: [DeTomaso] Trying to diagnose weak brakes
>      Your diagram refers to the shuttle valve, the proportioning valve
>    is
>      the hunk of metal in front trunk also but plumbed purely to the
>    front
>      brakes limiting output pressure by about 20% of input. It does
>    much the
>      same as a stepped master cylinder in compensating for woefully
>      undersized rear calipers. It was installed based on tires of the
>    day
>      etc. but modern rubber especially 335 on the rear significantly
>    alters
>      brake balance and wheel lockup front to rear.
>      Although referring to the wrong valve your postulation that air is
>      trapped in it might be a very valid one, that or it's probably
>      the master cylinder going bad. I have a Motive pressure bleeder
>    and it
>      makes the task an easy and one man operation, with no fear of
>    running
>      the reservoir dry during bleeding (yes we've all done it!).
>      As a general note removing or gutting the proportioning valve
>    should be
>      evaluated along with any brake component upgrade (note Mike said
>    he has
>      an aftermarket master cylinder). It is hard to get all the
>    components
>      matched perfectly right to ensure the front brakes lock up just
>    before
>      the rears, hence installation of a more modern adjustable brake
>      proportioning valve can provide the fine tuning to ensure that. I
>    would
>      strongly recommend everyone test their brakes for lockup
>    periodically
>      on a very quiet and wide stretch of asphalt, not only is that a
>    basic
>      safety test it also provides you a measure of what pedal force
>    locks up
>      the brakes, if only under the road conditions prevailing at the
>    time
>      Julian
> 
>    ____________________________________________________________________
>    _
>      From: DeTomaso <[1][7]detomaso-bounces at server.detomasolist.com> on
>    behalf
>      of Joseph F. Byrd, Jr. <[2][8]byrdjf at embarqmail.com>
>      Sent: Saturday, February 17, 2018 8:06 AM
>      To: 'Mike & Elizabeth Thomas'
>      Cc: 'List DeTomaso Forum'
>      Subject: Re: [DeTomaso] Trying to diagnose weak brakes
>      Forgive me, but after having to participate in several "Fault
>    Tree"
>      evaluations where we thought of ridiculous scenarios that could be
>      possible.
>      Given;
>      ~3 inches of travel before braking
>      Rear doing the most braking
>      The proportional valve is gutted
>      Assume;
>       Air is trapped in the proportional.  This would cause the first
>    master
>      cylinder piston to travel while not establishing front caliper
>    pressure
>      to move the second piston.   After 3" of pedal travel, the first
>    piston
>      makes contact with the second and now the rear caliper pressure is
>      devolved with majority rear braking.
>      However, one would expect the differential valve to give failure
>    lamp.
>      -----Original Message-----
>      From: DeTomaso
>    [[3][9]mailto:detomaso-bounces at server.detomasolist.com] On
>      Behalf Of Mike & Elizabeth Thomas
>      Sent: Saturday, February 17, 2018 10:37 AM
>      To: 'Mike Drew'; 'List DeTomaso Forum'
>      Subject: Re: [DeTomaso] Trying to diagnose weak brakes
>      Thanks, certainly the cheapest and least invasive approach.
>      -----Original Message-----
>      From: Mike Drew [[4][10]mailto:MikeLDrew at aol.com]
>      Sent: Friday, February 16, 2018 9:04 PM
>      To: Mike & Elizabeth Thomas <[5][11]mbefthomas at comcast.net>
>      Cc: List DeTomaso Forum <[6][12]detomaso at server.detomasolist.com>
>      Subject: Re: [DeTomaso] Trying to diagnose weak brakes
>      Mike,
>      Another note. If the Les Schwab people are so dumb that they don't
>    know
>      that DOT4 is just DOT3 with a higher boiling point, I.e. an
>    improved
>      product that is 100% interchangeable, I wouldn't trust them to do
>    a
>      proper job of filling and bleeding your brakes.
>      I suspect there is nothing really wrong. Carefully drive to a
>    friend's
>      house, one with good mechanical aptitude and an appetite for the
>    beer
>      you will bring on the passenger seat, and together just bleed the
>      brakes properly using a quality brake fluid. (I like ATE Typ 200,
>      available from Tire Rack, Summit and Amazon to I suspect). I have
>    a
>      feeling they will be perfect afterwards....
>      Mike
>      Sent from my iPad
> 
>    On Feb 16, 2018, at 18:50, Mike & Elizabeth Thomas
> 
>      <[7][13]mbefthomas at comcast.net> wrote:
> 
>     I've been working through trying to figure what seems like a
> 
>      weakness
> 
>     in my brakes on 6328.
>     How do they feel now?  There seems like a fair bit of pedal travel
>     before they start to hook up.  Once they hook, they're fine when
> 
>      I'm
> 
>     just in normal traffic and stop and go.  If I have to stomp down on
>     them, it just doesn't seem like they're biting very well.  If I
> 
>      have to
> 
>     really stomp on them, I can't get any wheel to lock up at all.
>     Current setup:  the brakes are stock Girling, rebuild in 2004.
> 
>      they've
> 
>     been fully bled at Les Schwab 6 months ago with DOT 3 (they
> 
>      wouldn't
> 
>     use DOT 4 as it was not spec).  Yes, they were aware that there
> 
>      were
> 
>     two nipples on the front, the tech that handled me has 2 or 3
> 
>      Panteras
> 
>     that come in through the year.  The flex lines were replaced with
>     stainless lines in 2004 when all of the calipers were rebuilt.  The
>     vacuum line from the engine to the tube and tube to booster is
> 
>      recent,
> 
>     about 3-4 years ago.  So far as I know, the proportioning valve has
>     been gutted, but not really sure nor know how to be sure.  The
> 
>      master
> 
>     is an early `80's GM/Cadillac replaced about 10 years ago, the same
> 
>      was
> 
>     in the car when I bought it in `04.  I've just replaced the
> 
>      Porterfield
> 
>     R4S pads.  It was rather cold day when I went out to burn them in
> 
>      so
> 
>     first speculation is that they are not fully `seasoned'.  However,
> 
>      they
> 
>     feel about the same as the previous 10-yr old R4S's, and that
> 
>      wouldn't
> 
>     explain the pedal travel.  The booster is original so far as I
> 
>      know.
> 
>     First question, how much pedal travel should there be before the
> 
>      pedal
> 
>     feels resistance the brakes start to take up?
>     So, what else can I check/do out to figure out why my brakes seem
> 
>      so
> 
>     lazy.  I will try to re-season them when the weather gets warmer,
> 
>      but
> 
>     that won't deal with pedal travel.  When brake booster starts to
> 
>      fail,
> 
>     how does that happen?  Gradually or all at once?
>     Your input is appreciated and eagerly awaited.  I'd like to get
> 
>      this
> 
>     figgered before the season starts as everything else is running a
> 
>      well
> 
>     as it ever has.
>     Thanks
>     Mike Thomas
>     Pres., Panteras Northwest
>     206-795-3302
>     Yellow '74 #6328
>     [1][8][14]www.panterasnorthwest.com
>    References
>     1. [9][15]http://www.panterasnorthwest.com/
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>    References
>      1. [20]mailto:detomaso-bounces at server.detomasolist.com
>      2. [21]mailto:byrdjf at embarqmail.com
>      3. [22]mailto:detomaso-bounces at server.detomasolist.com
>      4. [23]mailto:MikeLDrew at aol.com
>      5. [24]mailto:mbefthomas at comcast.net
>      6. [25]mailto:detomaso at server.detomasolist.com
>      7. [26]mailto:mbefthomas at comcast.net
>      8. [27]http://www.panterasnorthwest.com/
>      9. [28]http://www.panterasnorthwest.com/
>     10. [29]mailto:DeTomaso at server.detomasolist.com
>     11. [30]http://server.detomasolist.com/mailman/listinfo/detomaso
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> References
> 
>  1. mailto:mbefthomas at comcast.net
>  2. mailto:julian_kift at hotmail.com
>  3. mailto:byrdjf at embarqmail.com
>  4. mailto:mbefthomas at comcast.net
>  5. mailto:detomaso at server.detomasolist.com
>  6. mailto:detomaso at server.detomasolist.com
>  7. mailto:detomaso-bounces at server.detomasolist.com
>  8. mailto:byrdjf at embarqmail.com
>  9. mailto:detomaso-bounces at server.detomasolist.com
> 10. mailto:MikeLDrew at aol.com
> 11. mailto:mbefthomas at comcast.net
> 12. mailto:detomaso at server.detomasolist.com
> 13. mailto:mbefthomas at comcast.net
> 14. http://www.panterasnorthwest.com/
> 15. http://www.panterasnorthwest.com/
> 16. mailto:DeTomaso at server.detomasolist.com
> 17. http://server.detomasolist.com/mailman/listinfo/detomaso
> 18. mailto:DeTomaso at server.detomasolist.com
> 19. http://server.detomasolist.com/mailman/listinfo/detomaso
> 20. mailto:detomaso-bounces at server.detomasolist.com
> 21. mailto:byrdjf at embarqmail.com
> 22. mailto:detomaso-bounces at server.detomasolist.com
> 23. mailto:MikeLDrew at aol.com
> 24. mailto:mbefthomas at comcast.net
> 25. mailto:detomaso at server.detomasolist.com
> 26. mailto:mbefthomas at comcast.net
> 27. http://www.panterasnorthwest.com/
> 28. http://www.panterasnorthwest.com/
> 29. mailto:DeTomaso at server.detomasolist.com
> 30. http://server.detomasolist.com/mailman/listinfo/detomaso
> 31. mailto:DeTomaso at server.detomasolist.com
> 32. http://server.detomasolist.com/mailman/listinfo/detomaso
> 33. mailto:DeTomaso at server.detomasolist.com
> 34. http://server.detomasolist.com/mailman/listinfo/detomaso
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-------------- next part --------------
   Is there a kit for a blind spot indicator?

   DISCLAIMER NOTICE: This message and any accompanying attachments
   contain information
   from CHARLES G. ZAROULIS, M. D. that is confidential or privileged. The
   information is intended to be for the use of the individual or entity
   named above. If you are not the intended recipient, be aware that any
   disclosure, copying, distribution or use of the contents of this
   information is prohibited. If you have received this email in error,
   please notify the sender immediately by reply email and destroy all
   copies of the original email. Thank you very much.
   On Feb 17, 2018, at 2:37 PM, Mike Drew via DeTomaso
   <[1]detomaso at server.detomasolist.com> wrote:
   Mike,
   In answer to your last question:
   Yes, you are nuts. I think your car was great when I rode in it ten
   years ago or so and it has only gotten better over time, I think. If it
   was a POS then tearing it apart might be justified, but it's not, so
   it's not.
   Drive it and enjoy it!  :)
   We all know people who started with perfectly good cars and `improved'
   them to the point of complete immobility.  It takes rather a lot of the
   fun out of it.....
   Mike
   Sent from my iPad

     On Feb 17, 2018, at 11:33, Mike & Elizabeth Thomas
     <[2]mbefthomas at comcast.net> wrote:

      Not really.  Since I replaced my master some years ago, the brakes
     have

      never been what I would call `stellar', and starting just such a
     thread

      to get them figured out has been on my mind, but more pressing
     fixes

      were needed.  Now that the rest of the car is running better then
     it

      ever has, this is at the top of the list.

      `Course, doesn't it make sense that after years of tinkering this
     and

      that, everything seems to be coming together just as I'm
     contemplating

      a full tear down for a restoration of the metal/paint.  Am I nuts .
     .

      .  ?

      Thanks

      Mike T.

      From: Jeff Cobb [[3]mailto:jeffcobb1 at me.com]

      Sent: Saturday, February 17, 2018 11:03 AM

      To: Mike & Elizabeth Thomas <[4]mbefthomas at comcast.net>;

      [5]DeTomaso at server.detomasolist.com
     [6]DeTomaso at server.detomasolist.com

      <[7]detomaso at server.detomasolist.com>

      Cc: Jeff Cobb <[8]jeffcobb1 at me.com>

      Subject: Re: [DeTomaso] Trying to diagnose weak brakes

      Mike,

      Something strikes me as being out of order in the problem-cause and

      effect diagnosis of understanding and fixing your brake pedal
     travel

      problem in reading these back and forth mails. You write as if
     these

      problems just appeared.

      Seems that your real stated problem is;

      -1-perceived or really too much pedal travel.

      -2-cannot lock up wheels

      Also:

      -1-more brake dust on rear wheels versus the fronts.

      My questions are simple.

      -1-When this problem start?

      Not when you first noticed or recognized it, but when it first
     showed

      up.

      -2-Was this first time problem right after someone worked on it?

      -3-Has someone done any adjusting to the pedal unit?

      My brake work fixing history has taught me:

      --Your #1 and 2 make sense.

      --This type of problem #1 and #2 does not just show up

      --Also more rear dust than fronts indicates a brake bias imbalance.

        NEVER do rears have more dust than fronts on any car because of

      laminar air flow.

        The fronts always run hotter which   emits more gas and powder.

      --That GM masters NEVER give a tight brake pedal unless they are
     p/s

      pumped hydraulic boosted power brake function or

      using a vacuum booster with an electric motor vacuum pump.

        The vacuum should be between 16 to 21.

      My thoughts to cure your two stated problems.

      -1-Make sure the brake pedal to booster pushrod does not have any
     slack

      caused by wear and giving sloppy joints,

        That the first pushrod is set correctly so that the pedal is
     correct

      height from floor.

        the vacuum booster pushrod to master does not have too much

      clearance--Should be about .020".

      -2-Then bled your brakes in the correct order; RR-LR-RF-LF.

        while watching for air bubbles and any type of pad to rotor air

      clearances/movement so to give reasons.

        If doing above work makes no difference "which I would be
     surprised".

      -3- then you need to plug off the master outputs and see if master

      travel is non and rock hard.

       When all above is correct and still note problems then you problem
     is

      in the fluid/caliper/pad space.

      -4-If you had rubber lines you could pinch them off with vise grips
     and

      find the soft one.

        Since you do not then a temp gun and some hard 60mph stops will
     give

      you your temp rise to grip performance function.

        Do 3 stops then measure/record then do 6 or so more and read and

      write again.

        Axle temps should be same and fronts are always more.

        The lowest temp unit will be your problem.

      Thoughts:

      -1-I have had brake problems caused by owners spraying tire shine
     shit

      on their wheels. That crap coats and greases the rotors which then

      kills the pads from gripping.

      -2-Also calipers with rubber piston boots that retract the pads
     more

      than .002" will cause problems.

      -3-Also if the rotors are not dead center to caliper then weird
     stuff

      lives on. Calipers can be shimmed to center them.

         Jaguar did that on all of their XJS v12 cars and when I recently

      removed my Mangustas L rear caliper, mounting shims were present.
     Which

      was it first ever removal, so the factory did the shims because of

      manufacturing differences.

      If none of this allows the car to stop better then maybe your pads

      function temp range is not right for you.

       Take care,

      Jeff Cobb

      On Feb 17, 2018, at 10:45 AM, Mike & Elizabeth Thomas

      <[1][9]mbefthomas at comcast.net> wrote:

          Thanks all.  I am planning a full-on restoration of the car in
     a

        year

          or two, and running of fresh brake lines, master, etc. even if
     I

        do

          retain the original Girling brakes, will be on the list.  I
     will

        try a

          proper bleeding, and it may not be a bad idea to upgrade to

        whatever

          master I intend to use after the restoration.  I may consider

        going the

          full Willwood route, but as I never intend to track the car,
     that

        may

          be overkill.  If I stay with the Girling calipers, I'll
     certainly

        have

          them properly rebuilt.

          Mike Thomas

          From: Julian Kift [[2][10]mailto:julian_kift at hotmail.com]

          Sent: Saturday, February 17, 2018 8:20 AM

          To: Joseph F. Byrd, Jr. <[3][11]byrdjf at embarqmail.com>; 'Mike &

        Elizabeth

          Thomas' <[4][12]mbefthomas at comcast.net>; 'List DeTomaso Forum'

          <[5][13]detomaso at server.detomasolist.com>

          Cc: 'List DeTomaso Forum'
     <[6][14]detomaso at server.detomasolist.com>

          Subject: Re: [DeTomaso] Trying to diagnose weak brakes

          Your diagram refers to the shuttle valve, the proportioning
     valve

        is

          the hunk of metal in front trunk also but plumbed purely to the

        front

          brakes limiting output pressure by about 20% of input. It does

        much the

          same as a stepped master cylinder in compensating for woefully

          undersized rear calipers. It was installed based on tires of
     the

        day

          etc. but modern rubber especially 335 on the rear significantly

        alters

          brake balance and wheel lockup front to rear.

          Although referring to the wrong valve your postulation that air
     is

          trapped in it might be a very valid one, that or it's probably

          the master cylinder going bad. I have a Motive pressure bleeder

        and it

          makes the task an easy and one man operation, with no fear of

        running

          the reservoir dry during bleeding (yes we've all done it!).

          As a general note removing or gutting the proportioning valve

        should be

          evaluated along with any brake component upgrade (note Mike
     said

        he has

          an aftermarket master cylinder). It is hard to get all the

        components

          matched perfectly right to ensure the front brakes lock up just

        before

          the rears, hence installation of a more modern adjustable brake

          proportioning valve can provide the fine tuning to ensure that.
     I

        would

          strongly recommend everyone test their brakes for lockup

        periodically

          on a very quiet and wide stretch of asphalt, not only is that a

        basic

          safety test it also provides you a measure of what pedal force

        locks up

          the brakes, if only under the road conditions prevailing at the

        time

          Julian

        _________________________________________________________________
     ___

        _

          From: DeTomaso
     <[1][7][15]detomaso-bounces at server.detomasolist.com> on

        behalf

          of Joseph F. Byrd, Jr. <[2][8][16]byrdjf at embarqmail.com>

          Sent: Saturday, February 17, 2018 8:06 AM

          To: 'Mike & Elizabeth Thomas'

          Cc: 'List DeTomaso Forum'

          Subject: Re: [DeTomaso] Trying to diagnose weak brakes

          Forgive me, but after having to participate in several "Fault

        Tree"

          evaluations where we thought of ridiculous scenarios that could
     be

          possible.

          Given;

          ~3 inches of travel before braking

          Rear doing the most braking

          The proportional valve is gutted

          Assume;

           Air is trapped in the proportional.  This would cause the
     first

        master

          cylinder piston to travel while not establishing front caliper

        pressure

          to move the second piston.   After 3" of pedal travel, the
     first

        piston

          makes contact with the second and now the rear caliper pressure
     is

          devolved with majority rear braking.

          However, one would expect the differential valve to give
     failure

        lamp.

          -----Original Message-----

          From: DeTomaso

        [[3][9][17]mailto:detomaso-bounces at server.detomasolist.com] On

          Behalf Of Mike & Elizabeth Thomas

          Sent: Saturday, February 17, 2018 10:37 AM

          To: 'Mike Drew'; 'List DeTomaso Forum'

          Subject: Re: [DeTomaso] Trying to diagnose weak brakes

          Thanks, certainly the cheapest and least invasive approach.

          -----Original Message-----

          From: Mike Drew [[4][10][18]mailto:MikeLDrew at aol.com]

          Sent: Friday, February 16, 2018 9:04 PM

          To: Mike & Elizabeth Thomas <[5][11][19]mbefthomas at comcast.net>

          Cc: List DeTomaso Forum
     <[6][12][20]detomaso at server.detomasolist.com>

          Subject: Re: [DeTomaso] Trying to diagnose weak brakes

          Mike,

          Another note. If the Les Schwab people are so dumb that they
     don't

        know

          that DOT4 is just DOT3 with a higher boiling point, I.e. an

        improved

          product that is 100% interchangeable, I wouldn't trust them to
     do

        a

          proper job of filling and bleeding your brakes.

          I suspect there is nothing really wrong. Carefully drive to a

        friend's

          house, one with good mechanical aptitude and an appetite for
     the

        beer

          you will bring on the passenger seat, and together just bleed
     the

          brakes properly using a quality brake fluid. (I like ATE Typ
     200,

          available from Tire Rack, Summit and Amazon to I suspect). I
     have

        a

          feeling they will be perfect afterwards....

          Mike

          Sent from my iPad

        On Feb 16, 2018, at 18:50, Mike & Elizabeth Thomas

          <[7][13][21]mbefthomas at comcast.net> wrote:

         I've been working through trying to figure what seems like a

          weakness

         in my brakes on 6328.

         How do they feel now?  There seems like a fair bit of pedal
     travel

         before they start to hook up.  Once they hook, they're fine when

          I'm

         just in normal traffic and stop and go.  If I have to stomp down
     on

         them, it just doesn't seem like they're biting very well.  If I

          have to

         really stomp on them, I can't get any wheel to lock up at all.

         Current setup:  the brakes are stock Girling, rebuild in 2004.

          they've

         been fully bled at Les Schwab 6 months ago with DOT 3 (they

          wouldn't

         use DOT 4 as it was not spec).  Yes, they were aware that there

          were

         two nipples on the front, the tech that handled me has 2 or 3

          Panteras

         that come in through the year.  The flex lines were replaced
     with

         stainless lines in 2004 when all of the calipers were rebuilt.
     The

         vacuum line from the engine to the tube and tube to booster is

          recent,

         about 3-4 years ago.  So far as I know, the proportioning valve
     has

         been gutted, but not really sure nor know how to be sure.  The

          master

         is an early `80's GM/Cadillac replaced about 10 years ago, the
     same

          was

         in the car when I bought it in `04.  I've just replaced the

          Porterfield

         R4S pads.  It was rather cold day when I went out to burn them
     in

          so

         first speculation is that they are not fully `seasoned'.
     However,

          they

         feel about the same as the previous 10-yr old R4S's, and that

          wouldn't

         explain the pedal travel.  The booster is original so far as I

          know.

         First question, how much pedal travel should there be before the

          pedal

         feels resistance the brakes start to take up?

         So, what else can I check/do out to figure out why my brakes
     seem

          so

         lazy.  I will try to re-season them when the weather gets
     warmer,

          but

         that won't deal with pedal travel.  When brake booster starts to

          fail,

         how does that happen?  Gradually or all at once?

         Your input is appreciated and eagerly awaited.  I'd like to get

          this

         figgered before the season starts as everything else is running
     a

          well

         as it ever has.

         Thanks

         Mike Thomas

         Pres., Panteras Northwest

         206-795-3302

         Yellow '74 #6328

         [1][8][14][22]www.panterasnorthwest.com

        References

         1. [9][15][23]http://www.panterasnorthwest.com/

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          4. [23][31]mailto:MikeLDrew at aol.com

          5. [24][32]mailto:mbefthomas at comcast.net

          6. [25][33]mailto:detomaso at server.detomasolist.com

          7. [26][34]mailto:mbefthomas at comcast.net

          8. [27][35]http://www.panterasnorthwest.com/

          9. [28][36]http://www.panterasnorthwest.com/

         10. [29][37]mailto:DeTomaso at server.detomasolist.com

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     References

      1. [43]mailto:mbefthomas at comcast.net

      2. [44]mailto:julian_kift at hotmail.com

      3. [45]mailto:byrdjf at embarqmail.com

      4. [46]mailto:mbefthomas at comcast.net

      5. [47]mailto:detomaso at server.detomasolist.com

      6. [48]mailto:detomaso at server.detomasolist.com

      7. [49]mailto:detomaso-bounces at server.detomasolist.com

      8. [50]mailto:byrdjf at embarqmail.com

      9. [51]mailto:detomaso-bounces at server.detomasolist.com

     10. [52]mailto:MikeLDrew at aol.com

     11. [53]mailto:mbefthomas at comcast.net

     12. [54]mailto:detomaso at server.detomasolist.com

     13. [55]mailto:mbefthomas at comcast.net

     14. [56]http://www.panterasnorthwest.com/

     15. [57]http://www.panterasnorthwest.com/

     16. [58]mailto:DeTomaso at server.detomasolist.com

     17. [59]http://server.detomasolist.com/mailman/listinfo/detomaso

     18. [60]mailto:DeTomaso at server.detomasolist.com

     19. [61]http://server.detomasolist.com/mailman/listinfo/detomaso

     20. [62]mailto:detomaso-bounces at server.detomasolist.com

     21. [63]mailto:byrdjf at embarqmail.com

     22. [64]mailto:detomaso-bounces at server.detomasolist.com

     23. [65]mailto:MikeLDrew at aol.com

     24. [66]mailto:mbefthomas at comcast.net

     25. [67]mailto:detomaso at server.detomasolist.com

     26. [68]mailto:mbefthomas at comcast.net

     27. [69]http://www.panterasnorthwest.com/

     28. [70]http://www.panterasnorthwest.com/

     29. [71]mailto:DeTomaso at server.detomasolist.com

     30. [72]http://server.detomasolist.com/mailman/listinfo/detomaso

     31. [73]mailto:DeTomaso at server.detomasolist.com

     32. [74]http://server.detomasolist.com/mailman/listinfo/detomaso

     33. [75]mailto:DeTomaso at server.detomasolist.com

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References

   1. mailto:detomaso at server.detomasolist.com
   2. mailto:mbefthomas at comcast.net
   3. mailto:jeffcobb1 at me.com
   4. mailto:mbefthomas at comcast.net
   5. mailto:DeTomaso at server.detomasolist.com
   6. mailto:DeTomaso at server.detomasolist.com
   7. mailto:detomaso at server.detomasolist.com
   8. mailto:jeffcobb1 at me.com
   9. mailto:mbefthomas at comcast.net
  10. mailto:julian_kift at hotmail.com
  11. mailto:byrdjf at embarqmail.com
  12. mailto:mbefthomas at comcast.net
  13. mailto:detomaso at server.detomasolist.com
  14. mailto:detomaso at server.detomasolist.com
  15. mailto:detomaso-bounces at server.detomasolist.com
  16. mailto:byrdjf at embarqmail.com
  17. mailto:detomaso-bounces at server.detomasolist.com
  18. mailto:MikeLDrew at aol.com
  19. mailto:mbefthomas at comcast.net
  20. mailto:detomaso at server.detomasolist.com
  21. mailto:mbefthomas at comcast.net
  22. http://www.panterasnorthwest.com/
  23. http://www.panterasnorthwest.com/
  24. mailto:DeTomaso at server.detomasolist.com
  25. http://server.detomasolist.com/mailman/listinfo/detomaso
  26. mailto:DeTomaso at server.detomasolist.com
  27. http://server.detomasolist.com/mailman/listinfo/detomaso
  28. mailto:detomaso-bounces at server.detomasolist.com
  29. mailto:byrdjf at embarqmail.com
  30. mailto:detomaso-bounces at server.detomasolist.com
  31. mailto:MikeLDrew at aol.com
  32. mailto:mbefthomas at comcast.net
  33. mailto:detomaso at server.detomasolist.com
  34. mailto:mbefthomas at comcast.net
  35. http://www.panterasnorthwest.com/
  36. http://www.panterasnorthwest.com/
  37. mailto:DeTomaso at server.detomasolist.com
  38. http://server.detomasolist.com/mailman/listinfo/detomaso
  39. mailto:DeTomaso at server.detomasolist.com
  40. http://server.detomasolist.com/mailman/listinfo/detomaso
  41. mailto:DeTomaso at server.detomasolist.com
  42. http://server.detomasolist.com/mailman/listinfo/detomaso
  43. mailto:mbefthomas at comcast.net
  44. mailto:julian_kift at hotmail.com
  45. mailto:byrdjf at embarqmail.com
  46. mailto:mbefthomas at comcast.net
  47. mailto:detomaso at server.detomasolist.com
  48. mailto:detomaso at server.detomasolist.com
  49. mailto:detomaso-bounces at server.detomasolist.com
  50. mailto:byrdjf at embarqmail.com
  51. mailto:detomaso-bounces at server.detomasolist.com
  52. mailto:MikeLDrew at aol.com
  53. mailto:mbefthomas at comcast.net
  54. mailto:detomaso at server.detomasolist.com
  55. mailto:mbefthomas at comcast.net
  56. http://www.panterasnorthwest.com/
  57. http://www.panterasnorthwest.com/
  58. mailto:DeTomaso at server.detomasolist.com
  59. http://server.detomasolist.com/mailman/listinfo/detomaso
  60. mailto:DeTomaso at server.detomasolist.com
  61. http://server.detomasolist.com/mailman/listinfo/detomaso
  62. mailto:detomaso-bounces at server.detomasolist.com
  63. mailto:byrdjf at embarqmail.com
  64. mailto:detomaso-bounces at server.detomasolist.com
  65. mailto:MikeLDrew at aol.com
  66. mailto:mbefthomas at comcast.net
  67. mailto:detomaso at server.detomasolist.com
  68. mailto:mbefthomas at comcast.net
  69. http://www.panterasnorthwest.com/
  70. http://www.panterasnorthwest.com/
  71. mailto:DeTomaso at server.detomasolist.com
  72. http://server.detomasolist.com/mailman/listinfo/detomaso
  73. mailto:DeTomaso at server.detomasolist.com
  74. http://server.detomasolist.com/mailman/listinfo/detomaso
  75. mailto:DeTomaso at server.detomasolist.com
  76. http://server.detomasolist.com/mailman/listinfo/detomaso
  77. mailto:DeTomaso at server.detomasolist.com
  78. http://server.detomasolist.com/mailman/listinfo/detomaso
  79. mailto:DeTomaso at server.detomasolist.com
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