What bore size on master cylinder should I use?

Discussion in 'Engine/Drivetrain' started by Rynosaur, Mar 14, 2019.

  1. Rynosaur

    Rynosaur Member

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    71 hilux with the front disk conversion, Currently running a stock 90s mc. I believe it's a 9.5"/single. The brakes are scary and lock up during hard/fast braking. I'm assuming I need to go up on the bore size to reduce pressure. What are you running or what do you recomend?
     
  2. jetas

    jetas Grand Toyotaholic

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    Correct me if im wrong but doesnt going up in bore size increase pressure?
     
  3. fred heath

    fred heath Enthusiast

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    Your truck was never designed for front discs. What you need is a proportioning valve to allow different pressures to the front and rear brakes. Changing the m/c will not help in this case. Maybe find a later model parts truck and source the valve from there.
     
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  4. Rynosaur

    Rynosaur Member

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    Bigger bore = more flow/less pressure build up

    I think :lol:
     
  5. Rynosaur

    Rynosaur Member

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    I will defently look into this thank you, it current has a proportioning valve, maybe just needs to be replaced
     
  6. jetas

    jetas Grand Toyotaholic

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    Id try replacing the MC. On my 89 the MC went bad and the tires were locking up all over the place
     
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