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  • Brakes: Bleed sequence

    Easy question....after replacing the master cylinder should you bleed the hydrovac first or last. The manual is pretty vague on this but you would think the hydrovac would have to be bled before the wheels. Also since there is two bleed screws (one larger than the other) in the hydrovac which one of those is first. Sorry to display my ignorance but I only want to do this once if at all possible.

  • #2
    Originally posted by E. Davis View Post
    Easy question....after replacing the master cylinder should you bleed the hydrovac first or last. The manual is pretty vague on this but you would think the hydrovac would have to be bled before the wheels. Also since there is two bleed screws (one larger than the other) in the hydrovac which one of those is first. Sorry to display my ignorance but I only want to do this once if at all possible.
    MC first, then hydrovac, starting with the upstream bleed screw. Then the wheel cylinders: RR, LR, RF, and LF, respectively. It also helps to tap the hydrovac with a screwdriver handle periodically, while bleeding, in order to get the bubbles to float to the surface more quickly.

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    • #3
      I have never owned a Studebaker with power brakes. Joe's post above, seems to be correct to me. I might add...if you can enlist another human assistant, I have had best bleeding results, with the help of a strong, aggressive, "Pumper!" I have used the famous "mighty Vac" pump, and those little "brake bleeder" bottles, but nothing seems to work as good as a person vigorously pumping the brake pedal, then trying to push the pedal through the floorboard, as you open and close the bleeder screw.

      I have observed, in clear tubing, an air bubble park in a high spot, and watched fluid flow under the bubble, and the air remain under gentle pressure. It is the vigorous pumping, and aggressive purging, that really dislodges the air, and moves it to the point of release. One tiny air bubble, in a hydraulic system, with such a low volume as hydraulic brakes, close tolerances, little fluid flow, and very high mechanical ratio...the air bubble disrupts the operation immensely.
      John Clary
      Greer, SC

      SDC member since 1975

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      • #4
        Originally posted by jclary View Post
        I have never owned a Studebaker with power brakes. Joe's post above, seems to be correct to me. I might add...if you can enlist another human assistant, I have had best bleeding results, with the help of a strong, aggressive, "Pumper!" I have used the famous "mighty Vac" pump, and those little "brake bleeder" bottles, but nothing seems to work as good as a person vigorously pumping the brake pedal, then trying to push the pedal through the floorboard, as you open and close the bleeder screw.

        I have observed, in clear tubing, an air bubble park in a high spot, and watched fluid flow under the bubble, and the air remain under gentle pressure. It is the vigorous pumping, and aggressive purging, that really dislodges the air, and moves it to the point of release. One tiny air bubble, in a hydraulic system, with such a low volume as hydraulic brakes, close tolerances, little fluid flow, and very high mechanical ratio...the air bubble disrupts the operation immensely.
        Agree John,
        I have been using a, "Mighty Vac" for years now. In addition to the vacuum assist, it helps keep everything cleaner.

        First and foremost, I shoulda mentioned my two sons, who have long served as, "pumpers", ever since they needed multiple cushions behind them to reach the pedals. They have, "1-2-3-4-5-hold" down to a fine art now, and its easy to stay in synch during the operation.

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        • #5
          Thanks much guys....I have one of the best "brake bleeders" in the country in my wife. She has helped me so many times that we have it down to a routine and as you say we are in synch.

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