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Re: [sparrow_ev] Re: No Brakes

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  • SRWILS
    DOT 5 is the only way to go. I have it in all my older vehicles. Need to totally open the system and do a complete flush (even the wheel cylinders). Do a good
    Message 1 of 9 , Jan 1, 2007
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      DOT 5 is the only way to go. I have it in all my older
      vehicles. Need to totally open the system and do a
      complete flush (even the wheel cylinders). Do a good
      cleaning with Alcohol then blow out with compressed
      air. Do not mix DOT 5 with other types.

      Scot



      --- Sid Lloyd <sid.lloyd@...> wrote:

      > After sitting for 2 years, today I took out the
      > master brake cylinder
      > (not an easy chore...).
      >
      > It was gummed up with a brown sludge that solvent
      > didn't touch. But,
      > it cleaned up great with hot water and detergent.
      >
      > I have a rebuild kit on order and will get a
      > MightyVac to bleed the
      > master cylinder and the brake lines. Is everyone
      > using DOT 5 now?
      >
      > Sid
      >
      >


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    • edliz2001
      There s some pluses and minuses about the various brake fluids. I made the conscious decision to keep DOT 3 fluid in my 58 Ford and 66 Mustang because of
      Message 2 of 9 , Jan 2, 2007
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        There's some pluses and minuses about the various brake fluids. I
        made the conscious decision to keep DOT 3 fluid in my '58 Ford
        and '66 Mustang because of the compressibility of DOT 5 fluid.

        Here's an article comparing the various fluids:

        http://www.afcoracing.com/tech_pages/fluid.shtml

        With something as small as the Sparrow, it shouldn't be a real big
        deal which you use. I just don't like the "stepping on a tennis
        ball" feel of DOT 5, even after bleeding the system.

        Larry

        --- In sparrow_ev@yahoogroups.com, SRWILS <srwils@...> wrote:
        >
        > DOT 5 is the only way to go. I have it in all my older
        > vehicles. Need to totally open the system and do a
        > complete flush (even the wheel cylinders). Do a good
        > cleaning with Alcohol then blow out with compressed
        > air. Do not mix DOT 5 with other types.
        >
        > Scot
      • Richard Lewis
        I was under the impression that a car could not have the system changed to dot 5 after dot 3 had touched the seals. Am I wrong on that? ...
        Message 3 of 9 , Jan 2, 2007
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          I was under the impression that a car could not have
          the system changed to dot 5 after dot 3 had touched
          the seals.

          Am I wrong on that?


          --- edliz2001 <edliz2001@...> wrote:

          > There's some pluses and minuses about the various
          > brake fluids. I
          > made the conscious decision to keep DOT 3 fluid in
          > my '58 Ford
          > and '66 Mustang because of the compressibility of
          > DOT 5 fluid.
          >
          > Here's an article comparing the various fluids:
          >
          > http://www.afcoracing.com/tech_pages/fluid.shtml
          >
          > With something as small as the Sparrow, it shouldn't
          > be a real big
          > deal which you use. I just don't like the "stepping
          > on a tennis
          > ball" feel of DOT 5, even after bleeding the system.
          >
          > Larry
          >
          > --- In sparrow_ev@yahoogroups.com, SRWILS
          > <srwils@...> wrote:
          > >
          > > DOT 5 is the only way to go. I have it in all my
          > older
          > > vehicles. Need to totally open the system and do a
          > > complete flush (even the wheel cylinders). Do a
          > good
          > > cleaning with Alcohol then blow out with
          > compressed
          > > air. Do not mix DOT 5 with other types.
          > >
          > > Scot
          >
          >
          >


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        • Sid Lloyd
          Here s an article on the pros and cons: Battle of the DOTs DOT 3-4 Verses DOT 5. Which brake fluid should I use? From Oak Okleshen #35 With regards to the DOT
          Message 4 of 9 , Jan 2, 2007
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            Here's an article on the pros and cons:

            Battle of the DOTs
            DOT 3-4 Verses DOT 5. Which brake fluid should I use?

            From Oak Okleshen #35 "With regards to the DOT 3-4 verses DOT 5 brake
            fluid controversy, here is an article sent to me by Mr. Steve Wall. It
            is one of the most professional treatments I have seen on the subject".

            [I had to condense this article from 6 pages to 1 due to space
            limitations -ed]

            Brake Fluid Facts
            by Steve Wall

            As a former materials engineering supervisor at a major automotive
            brake system supplier, I feel both qualified and obligated to inject
            some material science facts into the murky debate about DOT 5 verses
            DOT 3-4 brake fluids. The important technical issues governing the use
            of a particular specification brake fluid are as follows:

            1. Fluid compatibility with the brake system rubber, plastic and
            metal components.
            2. Water absorption and corrosion.
            3. Fluid boiling point and other physical characteristics.
            4. Brake system contamination and sludging.

            Additionally, some technical comments will be made about the new brake
            fluid formulations appearing on the scene.

            First of all, it's important to understand the chemical nature of
            brake fluid. DOT 3 brake fluids are mixtures of glycols and glycol
            ethers. DOT 4 contains borate esters in addition to what is contained
            in DOT 3. These brake fluids are somewhat similar to automotive
            anti-freeze (ethylene glycol) and are not, as Dr. Curve implies, a
            petroleum fluid. DOT 5 is silicone chemistry.
            Fluid Compatibility

            Brake system materials must be compatible with the system fluid.
            Compatibility is determined by chemistry, and no amount of
            advertising, wishful thinking or rationalizing can change the science
            of chemical compatibility. Both DOT 3-4 and DOT 5 fluids are
            compatible with most brake system materials except in the case some
            silicone rubber external components such as caliper piston boots,
            which are attacked by silicon fluids and greases.
            Water absorption and corrosion

            The big bugaboo with DOT 3-4 fluids always cited by silicone fluid
            advocates is water absorption. DOT 3-4 glycol based fluids, just like
            ethylene glycol antifreezes, are readily miscible with water. Long
            term brake system water content tends to reach a maximum of about 3%,
            which is readily handled by the corrosion inhibitors in the brake
            fluid formulation. Since the inhibitors are gradually depleted as they
            do their job, glycol brake fluid, just like anti-freeze, needs to be
            changed periodically. Follow BMW's recommendations. DOT 5 fluids, not
            being water miscible, must rely on the silicone (with some corrosion
            inhibitors) as a barrier film to control corrosion. Water is not
            absorbed by silicone as in the case of DOT 3-4 fluids, and will remain
            as a separate globule sinking to the lowest point in the brake system,
            since it is more dense.
            Fluid boiling point

            DOT 4 glycol based fluid has a higher boiling point (446F) than DOT 3
            (401F), and both fluids will exhibit a reduced boiling point as water
            content increases. DOT 5 in its pure state offers a higher boiling
            point (500F) however if water got into the system, and a big globule
            found its way into a caliper, the water would start to boil at 212F
            causing a vapor lock condition [possible brake failure -ed.]. By
            contrast, DOT 3 fluid with 3% water content would still exhibit a
            boiling point of 300F. Silicone fluids also exhibit a 3 times greater
            propensity to dissolve air and other gasses which can lead to a
            "spongy pedal" and reduced braking at high altitudes.

            DOT 3 and DOT 4 fluids are mutually compatible, the major disadvantage
            of such a mix being a lowered boiling point. In an emergency, it'll
            do. Silicone fluid will not mix, but will float on top. From a
            lubricity standpoint, neither fluids are outstanding, though silicones
            will exhibit a more stable viscosity index in extreme temperatures,
            which is why the US Army likes silicone fluids. Since few of us ride
            at temperatures very much below freezing, let alone at 40 below zero,
            silicone's low temperature advantage won't be apparent. Neither fluids
            will reduce stopping distances.

            With the advent of ABS systems, the limitations of existing brake
            fluids have been recognized and the brake fluid manufacturers have
            been working on formulations with enhanced properties. However, the
            chosen direction has not been silicone. The only major user of
            silicone is the US Army. It has recently asked the SAE about a
            procedure for converting from silicon back to DOT 3-4. If they ever
            decide to switch, silicone brake fluid will go the way of leaded gas.
            Brake system contamination

            The single most common brake system failure caused by a contaminant is
            swelling of the rubber components (piston seals etc.) due to the
            introduction of petroleum based products (motor oil, power steering
            fluid, mineral oil etc.) A small amount is enough to do major damage.
            Flushing with mineral spirits is enough to cause a complete system
            failure in a short time. I suspect this is what has happened when some
            BMW owners changed to DOT 5 (and then assumed that silicone caused the
            problem). Flushing with alcohol also causes problems. BMW brake
            systems should be flushed only with DOT 3 or 4.

            If silicone is introduced into an older brake system, the silicone
            will latch unto the sludge generated by gradual component
            deterioration and create a gelatin like goop which will attract more
            crud and eventually plug up metering orifices or cause pistons to
            stick. If you have already changed to DOT 5, don't compound your
            initial mistake and change back. Silicone is very tenacious stuff and
            you will never get it all out of your system. Just change the fluid
            regularly. For those who race using silicone fluid, I recommend that
            you crack the bleed screws before each racing session to insure that
            there is no water in the calipers.
            New developments

            Since DOT 4 fluids were developed, it was recognized that borate ester
            based fluids offered the potential for boiling points beyond the 446F
            requirement, thus came the Super DOT 4 fluids - some covered by the
            DOT 5.1 designation - which exhibit a minimum dry boiling point of
            500F (same as silicone, but different chemistry).

            Additionally, a new fluid type based on silicon ester chemistry (not
            the same as silicon) has been developed that exhibits a minimum dry
            boiling point of 590F. It is miscible with DOT 3-4 fluids but has yet
            to see commercial usage.
          • Gregg D. Richie
            Sid, Thanks for sharing the article from Steve Walls. Very informative! Gregg D. Richie #123 Electron [Non-text portions of this message have been removed]
            Message 5 of 9 , Jan 3, 2007
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              Sid,

              Thanks for sharing the article from Steve Walls. Very informative!

              Gregg D. Richie
              #123
              Electron


              [Non-text portions of this message have been removed]
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