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Brake experience

Discussion in 'Gen 2 Prius Main Forum' started by fchung76, Jun 5, 2006.

  1. fchung76

    fchung76 New Member

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    I have a 2004 model.
    Whenever I slow down the vehicle gracefully (i.e. not hard stop), when it comes to about 1 second before the full stop, it feels as if the brake were released and depressed again. The speed of the car increases slightly and comes to a full stop. Do you have similar experience?
    Could it be due to the transition between the regen brake motor?
     
  2. seasalsa

    seasalsa Active Member

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    Yes, at about 9 MPH the system switches from regen to friction braking.
     
  3. jamarimutt

    jamarimutt New Member

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    I have a 2004 and have never had this experience. Being aware that others have reported this, and of the explanation given in the previous post, I have repeatedly attempted to duplicate this and it has never happened. <_<
     
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    Yep. That's the transition. I usually look out for it. That means prior to that, I was actually regenerating. If I don't feel that split second "lag" from the brakes, that meant I was pressing too hard and was using the friction brakes. This is one of the ways I learned out to gauge the max brake pedal angle for regeneration.
     
  5. McShemp

    McShemp New Member

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    <div class='quotetop'>QUOTE(fchung76 @ Jun 5 2006, 06:12 PM) [snapback]266300[/snapback]</div>
    Gotta ask ... are you the original owner or is this a 2004 you just acquired? It makes a difference in how I may respond.
     
  6. fchung76

    fchung76 New Member

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    I am the 2nd owner. Purchased it a year ago....
    Look forward to your insight.
     
  7. McShemp

    McShemp New Member

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    <div class='quotetop'>QUOTE(fchung76 @ Jun 6 2006, 12:13 PM) [snapback]266724[/snapback]</div>
    If you've owned the car for a year, and driven it, then I don't have any insight for you.

    If the brake "feeling" is a new sensation then have a dealer check it out. If it's happened all along, it's just as others have stated ... it's the way the transition between regen and mechanical brakes (and EV power) works.
     
  8. jmcclun

    jmcclun New Member

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    I have a new 2006 with 350 miles on it. In the testing phase of ownership I noticed this action and searched the site for responces. It is the release of the regen function and the application delay effect of the friction brakes. I only notice it when I creep to a stop (i.e. decel less than about 1 mph per 100 feet).
     
  9. Krash

    Krash Junior Member

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    I've noticed the same thing with our '06 except:
    1). it doesn't happen on every stop and,
    2). when it does occur the car jerks to a stop with many pulsations, (brakes on, brakes off).
    I figured it must have something to do with the regen system.
    I hope a software upgrade will eventually be offered to eliminate this herky-jerky characteristic.
    I hate trying to explain what's happening when I proudly demonstrate my new car.
     
  10. Bill Merchant

    Bill Merchant absit invidia

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    <div class='quotetop'>QUOTE(Krash @ Jun 7 2006, 10:54 AM) [snapback]267333[/snapback]</div>
    I don't think that is normal braking at all. I think something's broken. That sounds like the ABS, or maybe a faulty wheel sensor that is triggering ABS when you don't need it. I'd have the dealer look at it!
     
  11. bbielek

    bbielek New Member

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    My 2006 stops smoothly with no noticable transition, no jerking - nada. Just a smooth stop.
     
  12. keydiver

    keydiver New Member

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    My 2006 is somewhere between the 2 last posters, and just like most people described it: if I brake very gently to a stop, the regen releases once I drop below a certain speed, perhaps 9 mph as some suggested. At that point, you sometimes get the *illusion* that the car has accelerated, but it is only an *illusion*, as actually all that happened is the regen braking has released. At that point, I usually need to apply the mechanical braking just a little harder, to stop where I anticipated. But, my car never does any "herky-jerky" stops. The only "solution" is to wait longer to begin braking, and then brake harder, and the transition is barely noticeable. Not that I recommend those kinds of stops, but it does mask the transition. :rolleyes:
     
  13. hobbit

    hobbit Senior Member

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    Search the forums for "brakes grabbing" and the like. There's
    TONS of prior-art discussion about this.
    .
    _H*