Weird brake activity for a few minites

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by felix mizioznikov, Aug 8, 2016.

  1. felix mizioznikov

    felix mizioznikov Junior Member

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    Vehicle:
    2012 Prius
    Model:
    Two
    so today I'm driving around. It's been raining for a few days and no issues with the car but today I start up and notice the brakes are acting strange. Just a light tap in forward or reverse would almost lock them. This went on for 5 minutes in the parking lot as I was scared to hit the open road then after a few restarts and pumping the pedal it went back to normal.
    Anyone experience this? Never happened in my gen 3.
     
  2. Autoist

    Autoist Member

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    2016 Prius
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    Three
    May be rust on the rotor is causing a grabbier feel. Try this and see what happens afterwards:
    1. On a low traffic road come up to 40 mph.
    2. Shift to N (press shifter to left for 2 sec on left hand drive model)
    3. Break moderately hard to a stop.
    4. Shift back to D and now test the grabbiness of the brakes.
     
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  3. dangrass

    dangrass Junior Member

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    Two
    Just came back from a 500 mile trip out to the eastern Sierra and felt compelled to comment on the brakes of this car. To say that they are weird hardly does them justice. What I found was that the faster the vehicle speed, the more abrupt the braking becomes.

    What's disconcerting is that there is hardly any difference in pressure between "trail braking" and locking the wheels. In a "normal" car there is a significant difference in the amount of pressure between light braking and extreme braking, but with these cars there's very little difference.

    I find this to be a real problem...actually a major safety concern. I suspect that there will be many 2016 Prii that are rear-ended because of this. Sure hope it's something that Toyota can fix with a firmware update.
     
  4. Mendel Leisk

    Mendel Leisk Patron saint of newly poured sidewalks

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    Model:
    Touring
    I've noticed super-touchy brakes on our 2010, very infrequently, just in reverse, just at start up, for maybe a minute at most. Seems like something electronic is messed up, didn't boot properly.

    The first time it occurred I was backing up to exit a parallel parking spot, touched the brake, and was convinced I'd bumped the car behind: the stop was so abrupt.
     
  5. bisco

    bisco cookie crumbler

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    wow, sounds like gen 4 is really different!:eek:
     
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  6. wrprice

    wrprice Active Member

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    Vehicle:
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    Model:
    Four Touring
    My experience over 3k miles, including a 1300 mile road trip, is a bit different. I find the brakes to be extra grabby in the few occasions I've done an avoidance manoeuvre -- maybe PCS assisting behind the scenes? But in the first two weeks after switching from Gen3 I thought the Gen4 brakes were softer. I seemed to use more pressure or pedal travel to get the same response as I expected from Gen3 using a more nuanced brake pedal style.

    When I got my first Prius, switching from a US-manufactured car, the brake pedal was very different. I was told that US cars used a hydraulic system that was based on the amount of pressure your foot placed on the pedal, and that "Japanese" cars use a system that is based on pedal travel distance. What that meant to my foot was that I expected to need more force for the resistance of the US pedal, but the Prius pedal didn't offer the same resistance and my force translated to more pedal distance and "grabbier" brakes.
     
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