Brakes clicking/ticking when coming to a stop

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by winebuff08, Apr 26, 2008.

  1. winebuff08

    winebuff08 New Member

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    Forgive me for being a noob, but I bought a new 08 Prius the other day and am still getting used to some of its idiosyncracies.

    One thing I noticed on day two of ownership is this odd clicking or ticking of the brakes in the final stages of coming to a stop. It only happens if I am making a very gentle stop and never happens if I am really getting on the brakes. It does not happen at higher speeds; only at speeds say below 5MPH during deceleration as I am feathering the brake pedal out to execute a smooth stop. It's just a muted "click click click", perhaps three or four times as the car is gently rolling to a stop. Nothing violent at all. The sound is eminating from the lower front of the car, possibly more toward the right side than the left. There is no associated pedal feedback either as would possibly be the case with a bent rotor.

    Is the consensus that this is normal or is something wrong with my new Prius?

    Thanks for the replies...
     
  2. qbee42

    qbee42 My other car is a boat

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    Brake noise at low speed is normal. The Prius uses regenerative braking at speeds above seven mph; all you hear then is a whirring sound. At around seven mph the braking system switches over to the friction brakes, at which point you will hear noise from any rust or dirt on the brakes. Since the friction brakes are seldom used, they are often rusty and will make some noise. Many owners clean theirs from time to time by shifting into neutral and braking. In neutral the Prius uses only friction brakes, so doing this a few times will clean off the rust.

    Tom
     
  3. leftie1277

    leftie1277 New Member

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    My new 08 does the same thing...it was pretty annoying at first ( I thought something was wrong), but now I am used to it :)
     
  4. qbee42

    qbee42 My other car is a boat

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    Think of it as a small price to pay for having brakes that last 100,000 miles.

    Tom
     
  5. SebMike

    SebMike New Member

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    It may also be the accumulator pump, although I am not sure if I got the name right. Another feature in the braking system is that it will 'charge up' the hydraulics to more effectively brake. Similarly, it will 'discharge' that pressure after some amount of time. I often times hear the car 'discharge', sounds like a clickety-click-click, near the end of a stop.

    And, yes, noisy brakes and/or rotors and even something a little stuttering is not uncommon in those last few MPH while you feather the brakes to come to a smooth stop. That is unrelated to the brake accumulator pump noise, however.

    Mike
     
  6. qbee42

    qbee42 My other car is a boat

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    Good point. The brake accumulator pump makes a clicking or ratcheting sound about every third time you press the brakes. The sound comes from behind the driver's footwell.

    Tom
     
  7. winebuff08

    winebuff08 New Member

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    Thanks for all the input.

    I found the brake noise a little strange since I have never experienced it in another car unless there was a problem with the brakes. I figured there couldn't be much wrong on a brand new car but it is always a good idea to ask, especially when it comes to that part that stops the car. You just never know when something may have been put together wrong at the factory. :)

    The noise hasn't gone away or gotten any worse in the last week. It is still just a "click click click" in the last few moments of a very light stop, and only if brake pedal pressure is very light. Braking energy seems to be a little bit uneven when the noise is heard, not unlike if I were rapidly and lightly pumping the pedal. Anything over just light braking and it is not present at all.

    Just something unique, different and perhaps a little wierd...
     
  8. Dave

    Dave New Member

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    I took my 04 in for its 120,000 mile service today. Report says I have 80% front, 70% rear remaining. Not bad.
     
  9. kenny_081

    kenny_081 New Member

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    I just bought an 08 Prius; I put on about 350 miles when I started to notice the clicking sound from coming from near the break peddle area. It happens when I'm coming to a stop.

    However I also noticed its also present when I'm speeding up. After a certain speed, probably 10mph or 15mph, I get the same sound and it goes away.

    Its and on/off situation. Another member, in another thread, had a similar problem and was told it was something to do with the struts.

    If its only the breaks, will it go away? Should I take it to the dealer? It is annoying.

    Thanks!
     
  10. Bob64

    Bob64 Sapphire of the Blue Sky

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    if its doing that while your accelerating, then your probably talking about the brake accumulator pump... NOT the brakes.
     
  11. Keninca

    Keninca Junior Member

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    Other than Kenny 081 you've all described my biggest beef with these cars. I've had 2 (an 05 and an 07) and was hoping that the brake control software was modified to eliminate this in 08, but guess not :-( .

    In engineering terms, the smoothest stop is when dv/dt^2 approaches 0 as v approaches 0.

    As the car gets closer to stopping you've learned over time to gradually release the pressure on (feather) the brake pedal. If you do it very well, the actual stop becomes undetectably smooth. (I call it my "limo" stop.)

    UNFORTUNATELY: as the Prius mechanical brakes take over at 7mph, the Prius sensor / control system is unable to read / reproduce this gradual removal of brake pedal pressure and turn it into the corresponding gradual reduction of braking pad force (which happens naturally in the mechanical / hydro systems in other cars.)

    I remain frustrated in a good solution: If anyone has one I'd appreciate hearing it

    Thanks

    Ken
     
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