Should I have pressure on brake pedal?

Discussion in 'Gen 2 Prius Main Forum' started by Bronze84, Nov 6, 2013.

  1. Bronze84

    Bronze84 Member

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    Hi guys

    Would like to get some info regarding the brake pedal on my Prius.

    When it is completely turned off the brake pedal doesn't build any pressure. In previous cars I have had the brake pedal would build pressure and then release that pressure when the ignition was started. My pedal only has ever so slight pressure and is able to go all the way down to the pedal stop.

    Is this normal or could it be something wrong?

    I have a Toyota Warranty until Jan 2014 so was thinking about taking it in for a free health check. If there was something wrong with my brakes then it'd get done under warranty before it runs out

    Cheers chaps


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  2. hlunde

    hlunde Member

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    What you describe is a characteristic of a vacuum brake booster which is not used in a Prius. Prius uses a gas- charged hydraulic accumulator -- which was the subject of the early-production GenIII recall.
     
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  3. Britprius

    Britprius Senior Member

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    Hi Martin, This is normal for the Prius as it has a brake pedal stroke simulator effectively built on top of the hydraulic brakes. This is so that the pedal feels like a normal hydraulic pedal while you are using regen braking.
    As well as this the Prius does not use vacuum "servo" assist brakes as the engine does not run all the time. It uses an electric fluid pump that pushes fluid into a pressure bottle. This pressure is released to give a servo effect when using the hydraulic brakes.

    John (Britprius)
     
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  4. Britprius

    Britprius Senior Member

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    Martin, check this out. The brake circuit (hydraulic) for the Prius.
    brake map.jpg

    John (Britprius)
     
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  5. bisco

    bisco cookie crumbler

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    when i open the drivers door, the brake accumulator kicks in. by the time i sit and put my foot on the brake, it feels normal. yours should too.
     
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  6. Bronze84

    Bronze84 Member

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    Chaps, as always many thanks for the replies and the reassurance. Panic over! Lol! I may just take it for a health check anyway as my warranty is running out so would be a good way of finding any potential issues and getting them done under warranty, what do you guys reckon?!


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  7. bisco

    bisco cookie crumbler

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    probably a good idea, how many miles on her and what is your warranty?
     
  8. Bronze84

    Bronze84 Member

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    74k miles. And it's a full 1yr Toyota dealer warranty


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