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2005 Prius Brake inconsistency

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by BritBug, Mar 21, 2013.

  1. BritBug

    BritBug Junior Member

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    Okay, so I just purchased this car & thought there may be a learning curve to dealing with the brakes, but I think it may be abnormal. Hoping to get opinions on what this might be.

    When braking, I apply more & more pressure smoothly down on the brakes, but no matter how evenly, slowly, and smoothly I try to remain when braking, there is a point when it abruptly brakes to jolt the passengers forward and make me look like a terrible driver, lol. It provides for a smooth decline in speed until I'm almost stopped, then it does it. Jerks us to a stop. So I've learned to apply even pressure and right before that is about to occur, lift up on the brakes and restart that slow pressure to avoid it happening.

    I can deal with this because it's not that big of an inconvenience once I've gotten used to it, but I am just worried it may turn into something more or who knows, could be an easy fix. I had the car inspected by a Toyota dealership before I purchased it, and they said that everything was in great condition aside from windshield wipers. It has 81,000 miles, one owner, clean carfax.

    This is my first "new thread", so I really hope it's not a stupid question :)
    Thanks everyone.
     
    #1 BritBug, Mar 21, 2013
  2. SteveLee

    SteveLee Active Member

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    Not a stupid question at all. What you are experiencing is a little disturbing at first but it is normal for the car. The regenerative braking kicks in when you let off the accelerator, while it slows faster than it would without the regen factor and saves on the needed braking also allowing longer life for the brakes. It increases the generating power with the increasing pressure on the brake peddle. The recaptured energy provides charge to the HV battery. The regen braking is engaged until 6-8 mph, then it disengages and returns to only braking. There is a noticeable change in the braking at this point.

    Sounds like you are naturally adjusting to this difference. One other way to adjust to the way the car works is to begin slowing sooner and using less braking. This will increase fuel mileage, get more life from your brakes, allow smoother braking, and provide more recaptured energy to the HV battery.

    Congrats on your purchase, welcome to the Prius community. Enjoy!
     
    #2 SteveLee, Mar 21, 2013
    BritBug likes this.
  3. jdenenberg

    jdenenberg EE Professor

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    The transition to friction braking at ~7mph should not be harsh. Try cleaning the rotors:
    1. Get up to 25-30 mph on a road with no traffic.
    2. switch into neutral (N) to shut down regenerative braking.
    3. apply the brakes lightly and listen to the scraping sound of the brakes.
    4. repeat a few times and the scraping noise should be reduced as the rust is cleaned off.
    The transition should then be less abrupt.

    If this does not help, take your Prius to Taylor's Auto in Sanford NC (a qualified independent hybrid repair facility) to have him go over your braking system.

    JeffD
     
    #3 jdenenberg, Mar 21, 2013
    BritBug likes this.
  4. BritBug

    BritBug Junior Member

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    THANK YOU! I had no idea that it switched from regenerative to normal and I did notice it's at exactly 7mph!

    I will let you know how trying this out goes. Thank both of you!!!
     
    #4 BritBug, Mar 22, 2013
    Chuck Hughes likes this.
  5. BritBug

    BritBug Junior Member

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    Wow, thank you Jeff. I tried this, and throughout braking today I had a noticeable difference. The jerking changed to more of a rolling from one type to the other. It is still noticeable but not abrupt.
     
    #5 BritBug, Mar 22, 2013
    jdenenberg likes this.
  6. edthefox5

    edthefox5 Senior Member

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    If you get really good at it you'll put the car in neutral quite often when coming to a stop. Stop a few times during the day in friction only and that abrupt braking will stop. But if you store the car outside it will be very frequent
    especially after a rain.
     
    #6 edthefox5, Mar 22, 2013
  7. dhancock

    dhancock 2 Prius Family

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    This regen braking is the primary reason that PRIUS BRAKES LAST A VERY LONG TIME!:)
    It also the reason that Prius brakes tend to develop surface rust.
     
    #7 dhancock, Mar 23, 2013
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