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Best brake fluid?

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  • #16
    Thomas, I really don't think moisture is a problem with Dot5. My experience in the land of ice and snow certainly indicates that. You have to remember that Dot5 was originally developed for use by the US military in the high Arctic where moisture freezing would definitely be a problem. As to sprited driving, it is not recommended for racing, but otherwise it performs particularly well in normal hard driving.


    • #17
      I'm watching this discussion with much interest... especially since there are conflicting opinions!

      Please continue!

      Robert (Bob) Andrews- on the IoMT (Island of Misfit Toys)
      Parish, central NY 13131


      • #18
        Not even the military considers Dot5 to be a lifetime fill, they have a service spec.

        I wasn't the guy who made the laws of nature. Heat then cool = moisture attraction. Regular brake fluid mixes the moisture throughout, silicone brake fluid gathers the moisture in low places.

        Practical reality check: most people NEVER change the brake fluid in their cars. Apparently without much ill effect. In other words, most people don't know what boiling brake fluid induced brake fade is like. Until they have a serious panic stop - and then they want to say their brakes weren't working when they hit the (fill in the blank).

        Second practical reality check: for most Dot5 filled hobby cars seeing limited driving and garage storage, the rate of moisture accumulation will be slow. Same with Dot3.

        It actually takes some pretty dramatic braking to reveal a lowered brake fluid boiling temperature. This is why I mentioned mountain driving - without knowing what your version of normal hard driving.

        Seriously, I believe you when you say you went 100k plus miles over 16 years on the original Dot5 fill. There are guys who have done the same with Dot3. Doesn't mean that the brake fluid performance 16 years on is the same as when the fluid was fresh.

        I like Dot5, don't get me wrong. Its just that neither is immune to nature.


        Long time hot rodder
        Packrat junk collector
        '63 Avanti R2 4 speed


        • #19
          I have never in all my years of working with Dot5 fluid seen any evidence of moisture in the braking system. That said, both my "everyday drivers" had Delco braking systems that are particularly well sealed and with bladders on the master cylinders. If moisture "pooling" was going to be a problem, it would have shown up during our cold Canadian winters. The braking performance of both of these vehicles was excellent and would essentially stand the vehicles on their noses if required. Our Jeep was used to pull trailers, and also made at least a dozen trips loaded with a family of four to Florida. I recall narrowly avoiding T-boning a car with Xmas packages blocking the windows that pulled across in front of me while driving the old Chev. With all four tires screeching, I missed hitting the passenger door by mere inches. I wish I had that braking performance with my current vehicles. I'm not a fan of ABS, by the way. I'm interested in learning of any real life evidence of moisture contamination or "pooling" with Dot5 fluid.


          • #20
            The owners's manuals of my two newish daily drivers (one foreign one domestic) both require the brake fluid to be changed every 2 mention of mileage.

            On ANY car using ANY fluid, I'd change it every two years. Certainly with DOT 3. At the least with DOT 5, I'd run a pint or two through the system, bleeding each wheel.

            I know some have gone decades without changing fluid and gotten away with it. I ran with scissors once and didn't hurt myself .

            If the car quits running, that's inconvenient. It it won't stop, that's deadly.

            Dick Steinkamp
            Bellingham, WA

            Dick Steinkamp
            Bellingham, WA


            • #21
              As per the factory manuals for our current daily drivers, I change the Dot3 fluid every 3 years. My experience shows it to be pointless to flush Dot5. No harm in doing it though.


              • #22
                This thread should clear up alot of brake fluid myths.


                63 Avanti R2, 4-Speed, 3.73 TT
                Martinez, CA


                • #23
                  quote:Originally posted by bams50

                  I'm watching this discussion with much interest... especially since there are conflicting opinions!

                  Please continue!

                  Robert (Bob) Andrews-
                  [:0][:0][:0] HERE? CONFLICTING OPINIONS? BP
                  We've got to quit saying, "How stupid can you be?" Too many people are taking it as a challenge.

                  Ayn Rand:
                  "You can avoid reality, but you cannot avoid the consequences of avoiding reality."

                  G. K. Chesterton: This triangle of truisms, of father, mother, and child, cannot be destroyed; it can only destroy those civilizations which disregard it.


                  • #24
                    I use Dot 3.

                    Can't afford Dot 5.


                    Matthew Burnette
                    Hazlehurst, GA


                    • #25
                      I still feel that water accumulation in Dot5 fluid is a myth. If water is getting into the system at the cylinders, then Dot5 will surely be coming out. Having bled many Dot5 systems over the years, I have never seen any evidence of water in the clear container, and it would surely be visible since the two fluids are not miscible. Technical papers are one thing, but practical analysis trumps that.


                      • #26
                        Can anyone tell me how much neetsfoot oil should be put in the Hydravac system? Is the a substitute to neetsfoot oil?
                        brian C