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Disturbing Sensation when Stopping

Discussion in 'Gen 2 Prius Technical Discussion' started by PriusCrazy, Apr 11, 2009.

  1. PriusCrazy

    PriusCrazy Blizzard Pearl for Me

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    Hello everyone, my first post on the "general forum", I've been over on the 2010 Prius forum for a few weeks now... anxiously waiting ...

    Yesterday I test drove a new 2009 and noticed a couple of times when the car came to a stop it made a disturbing "bumping sound". If it had happened in one of the cars I own, I would have assumed a transmission problem. It seems as though something was disconnecting or disengaging. The stops were not hard or quick, but what I would consider usual driving.

    Is this normal for a Prius? Is it cause for concern? Thanks to all who respond.
     
    #1 PriusCrazy, Apr 11, 2009
  2. Paradox

    Paradox Prius Enthusiast / Moderator
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    When the car is first started and not really warmed up much, you can feel the engine when it shuts down, and sometimes it has a bump/thump sound to it. Not anything to worry about, just different from a normal car. You become so used to the different noises/sensation of driving the Prius after a while that you don't even notice it past a few months into ownership...
     
    #2 Paradox, Apr 11, 2009
  3. firepa63

    firepa63 Former Prius Owner

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    It also could be the transition from regenerative braking to friction braking. Sometimes there is a split-second feeling that the brakes are not working.
     
    #3 firepa63, Apr 11, 2009
  4. zonie911

    zonie911 Member

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    Hi- I have a magnetic gray '09. There are so many things that are totally different from a regular auto, sounds, ways of driving, etc.
    Keep reading this forum and others, there are a lot of good sites out there for info, check out "John's Stuff" for one.
    But, take my word for it, "you're gonna love, love, love it".
     
    #4 zonie911, Apr 20, 2009
  5. 2009Prius

    2009Prius A Wimpy DIYer

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    #5 2009Prius, Apr 27, 2009
  6. a priori

    a priori Canonus Curiosus

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    Did you notice anything other than this "bumping" sound? Was the gasoline engine running the entire time? Did you "feel" anything different during the braking? Was it just before you came to a complete stop or at some other point or points in the process of braking to a stop?

    Sorry for the onslaught of questions, but I'm just trying to figure out what it could be. The most often-discussed disconcerting thing during braking is the transition point from regenerative braking to use of the physical brakes. This happens somewhere around 7mph, unless you are in a heavy, quick-demand braking event.

    The issue arises when you are in a "normal" slow-speed braking event coming up to a stop sign on a city or suburban street. What happens is that you feel, for a brief second, as though the brakes have given way and that you'll not be stopping. Before you can physically react to the event, though, you notice the car slows. If you haven't driven in a little while, you'll also hear a squeak as the rust is knocked off the front discs!
     
    #6 a priori, Apr 27, 2009
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