Banging brakes ('04) - please help diagnose

Discussion in 'Gen 2 Prius Main Forum' started by Eisenson, Jul 5, 2008.

  1. Eisenson

    Eisenson New Member

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    '04, 55k miles.

    Not my first post on the subject...

    As the car comes to a halt (last 1mph or less), 10-20% of the time there will be an irregular but fairly loud banging from the suspension/braking system. The sound is about what you'd expect if a full soda can were freely rolling in a constrained space. Passengers randomly report LEFT/RIGHT, FRONT/REAR, but all agree that it is DOWN.

    Twice, the dealer found nothing.
    I've pulled the wheels and examined the brakes/suspension carefully, and found nothing.

    There is nothing rolling around in the car. No wheel is cracked. Wheel trim rings have been removed. All lug bolts are properly torqued. Brake pads and shoes are in excellent shape, and rear shoe assemblies are properly lubricated with the right stuff. There's no lube on the shoes or pads. All strut bolts are properly torqued. All strut mounts are properly welded and show no cracks.

    This has been going on for months as I wait for a major component failure that will provide a retrospective diagnosis, but so far the car is performing brilliantly except for that single problem.

    The dealer brought in a Japan-trained master mechanic who replicated the phenomenon, but has no idea of its cause.

    Very frustrating!

    ???
     
  2. Betelgeuse

    Betelgeuse Active Member

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    Is there any feeling to go along with this sound? In other words, is the banging accompanied by the feeling of a thump?

    The only thing I could think of is that maybe one of the motor mounts (or whatever is the equivalent in the Prius) may be going bad?
     
  3. Eisenson

    Eisenson New Member

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    Good points.

    First, there is at most the very slightest "feeling" accompanying the noise. As mentioned, it's as faint as that which might be produced by a full soda can rolling a foot and hitting a firm surface. The phenomenon occurs ONLY in the last second of a stop, as the wheels stop turning.

    And thanks - I forgot to mention. The event occurs whether the engine is turning or not. I have the ScanGauge installed and can tell.
     
  4. usbseawolf2000

    usbseawolf2000 HSD PhD

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    This may not be the same issue but my only experience with the brake noise.
    Did you get the brake acturator noise fix done? Mine sounded like a dog barking or bird charping. It makes that sound after the car stops.
     
  5. Eisenson

    Eisenson New Member

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    Hmmm.... I don't know if that was done or not, but this car has seen the dealer once in a while for other fixes, so presumably that was done and I just don't remember. I'll ask the dealer on Monday -- and THANKS.
     
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