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"Grabby" brakes at dead crawl

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by pdhenry, Aug 26, 2008.

  1. pdhenry

    pdhenry It's HEEERE!

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    This is a bit hard to describe. Particularly with the engine cold, when I apply light pressure to coast easily to a stop, just before stopping (1 or 2 mph tops) the calipers feel grabby and I can hear a medium pitch clunk-clunk-clunk sound from the front end somewhere. Each clunk corresponds to a grab feeling on the brakes.

    This is not the 7 mph threshold where the car transitions from regen to friction braking, but just before stopping

    I had an old minivan that would make a similar noise when I applied the brakes backing up - it ended up that the calipers were coming loose. Not that I think something similar is wrong, but what is it?

    I'm afraid that the shop response will be "we don't feel/hear anything wrong" or "they're all like that."
     
    #1 pdhenry, Aug 26, 2008
  2. efusco

    efusco Moderator Emeritus
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    Try this...

    Get up to speed...40mph or so, it isn't important but you probably want to stay below 41mph to avoid the ICE staying on. Put the car in neutral and brake to a stop....rinse and repeat once or twice.

    More than likely you've just got a bit of rust and corrosion on your brakes b/c they don't get used enough to keep them polished. The neutral brake trick prevents regen braking and the extended friction braking will polish them up.
     
    #2 efusco, Aug 26, 2008
  3. qbee42

    qbee42 My other car is a boat

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    You need to clean your brakes. The get used so little in the Prius that they tend to get rusty.

    Find an empty stretch of road, get up to about 35 mph, shift into N, and brake until you slow down to about 20. Repeat this a few more times as necessary.

    Shifting into N forces the Prius to use only friction brakes, which lets you clean them with a little heavier braking.

    Tom
     
    #3 qbee42, Aug 26, 2008
  4. pdhenry

    pdhenry It's HEEERE!

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    Coming home from work I couldn't get it to happen. I did do one or two Neutral brakes on the way so maybe that helped.

    Come to think of it, this might be more prevalent in the morning after the dew has had a chance to sit on the disks for a few hours.

    Thanks. :)
     
    #4 pdhenry, Aug 26, 2008
  5. qbee42

    qbee42 My other car is a boat

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    It is more common in the morning. All of my Hondas used to do that. Each morning I would scratch and scrape out of the drive, then the brakes would clean off and all would be good until the next day.

    Tom
     
    #5 qbee42, Aug 26, 2008
  6. snowbird

    snowbird Junior Member

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    OK, maybe that helps me too. I was having that " grabby" problem during a rainstorm the other morning - no clunky sound though.
     
    #6 snowbird, Aug 27, 2008
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