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Brake noise & feel normal?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by canesfan, May 9, 2008.

  1. canesfan

    canesfan Culture shocked...

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    I have looked at some of the threads about brakes, but want to ask my question anyway. Just got my Prius the other day and I have noticed that if I am really having to brake, vs. just easing to a stop, I get this thunking sound and grabby feel. I stop with no problem and I just want to find out if this is normal. It doesn't happen if I am able to coast or brake gently to a stop. Thank you.
     
  2. richard schumacher

    richard schumacher shortbus driver

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    Sounds typical. The can be rusty because they don't get used much; and the rate of application is both variable and rather different than pure friction brakes, and that takes some getting used to.
     
  3. canesfan

    canesfan Culture shocked...

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    I got my Prius two days ago. Could they already be rusty?
     
  4. richard schumacher

    richard schumacher shortbus driver

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    Recall that your Prius spent a month on a ship and some additional days or weeks being transported and prepped for delivery.
     
  5. canesfan

    canesfan Culture shocked...

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    Thank you, I guess I won't worry then. Should I try what I've read about putting the car in Neutral and braking? How many times in a row do you have to do that to get the crud off the brakes?
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, it would not hurt to try that. Look at the front discs and see if they are shiny, or have a light layer of rust. If the latter, then work on them until they are shiny.

    If they already look nice & shiny, then there's no need to worry.
     
  7. canesfan

    canesfan Culture shocked...

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    If they do look nice & shiny, then what is causing the things I described?
     
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    First off, it is good that you are experimenting with your car and assessing its behavior under a variety of driving situations. Under normal conditions where you are braking gently or moderately, most of the braking will be regen braking until your speed drops down to ~6 mph.

    If you make a panic stop, the Prius will shift from regen braking to friction braking. The "grabby feel" might be due to residue on the brake pads. Try getting up to 45 - 50 mph, then shift to N and brake moderately. Repeat several times and then see if the "grabby feel" improves.

    The "thunking sound" might be front suspension noise as the coil springs compress when you are making a hard stop.
    See above.
     
  9. richard schumacher

    richard schumacher shortbus driver

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    The other feature named above: "the rate of application is both variable and rather different than pure friction [that is, conventional car] brakes, and that takes some getting used to". Give it a few weeks and see how it feels then.
     
  10. canesfan

    canesfan Culture shocked...

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    From Richard: "First off, it is good that you are experimenting with your car and assessing its behavior under a variety of driving situations. Under normal conditions where you are braking gently or moderately, most of the braking will be regen braking until your speed drops down to ~6 mph.

    If you make a panic stop, the Prius will shift from regen braking to friction braking. The "grabby feel" might be due to residue on the brake pads. Try getting up to 45 - 50 mph, then shift to N and brake moderately. Repeat several times and then see if the "grabby feel" improves.

    The "thunking sound" might be front suspension noise as the coil springs compress when you are making a hard stop."

    Me: I have not yet tried the process of putting it in "N" to clean the brake pads. I looked at the brakes and they do seem clean and shiny. However, this afternoon the "grabby feel" seemed less than before, could've been my driving or maybe something is getting broken in or cleaned up. I was not making any panic/hard stops when this was occurring, just slightly more firm than usual. If the thunking sound IS front suspension noise is that a problem or normal? Since I have had the car only two days I am pretty much trusting that all these interesting sounds and sensations are normal as no warning lights have appeared.
     
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  11. chriscard25

    chriscard25 New Member

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    These sounds are normal....rest assured, if they get happen to get worse, you have warranty to rely on.
    FYI, had mine for about 6 weeks--just now getting used to the different sounds this car makes.....
     
  12. hobbit

    hobbit Senior Member

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    Rotors can start to surface-rust in mere HOURS in wet weather.
    This pic shows what can accumulate in only a day or so, and
    the "neutral trick" is definitely needed to even things out again.
    It's not a lot of brake usage or [ooh ooh] energy loss to
    get them clean and smooth again, but in the meantime will feel
    like your pads are grabbing sandpaper.
    .
    _H*
     
  13. canesfan

    canesfan Culture shocked...

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    I checked out your pic and mine do not look like that at all. I can't see any rust at all on mine.
     
  14. dustyhuskie

    dustyhuskie Itchy Tomato

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    I don't know if we are talking about the same issues. I also have brakes that make loud scraping noises. It is worse in the winter and after rain. It happens the first 3-5x I brake and then goes away.

    The neutral trick doesn't solve the problem. It is obviously the friction brakes making the noise since braking in neutral results in one long noisy stop. The brakes make the same noise when I start the car up again.

    What is odd is that not all Priuses have this problem. No one I personally know has had this issue consistantly. Other Priuses I've driven don't seem to have the problem.

    I had the dealer check the brakes. There is nothing wrong with them. I have just learned to live with the noise.
     
  15. rpg51

    rpg51 Member

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    I noticed that breaking with my new Prius has a very different feel to it than normal cars. I attribute it to the regeneration that is going on and I assume it is just something that you need to adjust to - which I already have after a couple of weeks. The breaks feel very touchy for a while.

    I did notice one thing that bothered me a bit but again I assume its just part of the Prius design - after driving a long while at highway speed I exited and and came to a stop in traffic on the ramp - it was a fairly hard stop. I noticed an odd clunking when ever I moved slightly forward in traffic and then stopped again. Almost like two clunks. Again - I'm not worried about it but it would be nice to here others confirm this is normal. The breaks work very well by the way - they just feel a bit different and it takes some getting used to.
     
  16. richard schumacher

    richard schumacher shortbus driver

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    Do you ease up on the brake pedal as you slow down? Keeping the same pressure can often result in a grabby stop.
     
  17. rpg51

    rpg51 Member

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    Here is what mine is doing - as I break to a stop, just as I am almost completely stopped, I here a small clunk and it feel like the brakes release slightly and then come on again - all this with steady foot pressure and at very slow speed - it doesn't happen until I am almost stopped. Its almost like the brakes are pumping automatically - not like the abs brake feeling you get in slippery conditions- its just a single pump and release.
     
  18. richard schumacher

    richard schumacher shortbus driver

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    Yes, after four years that's exactly what mine does, if I keep steady pedal pressure. Remedies: get used to it, or modulate pedal pressure as you come to a stop.
     
  19. dustyhuskie

    dustyhuskie Itchy Tomato

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    I actually have to brake harder when the friction brakes engage. Otherwise. the car doesn't continue to slow down. Found this out after I ended up in the intersection a couple of times.

    I have never heard a clunking noise but perhaps it is just the ICE turning off and I haven't noticed it. The vibration is probably more noticable at lower speeds when there is no distraction from road vibrations. You can try to recreate this by starting the car in the driveway and cranking up the heat. The ICE will come on and then turn off when the car is heated up.
     
  20. geeky teacher

    geeky teacher New Member

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    When my Prius began making unusual brake noise I came to the PriusChat gurus. Based on their discussions I decided to have the brake actuator assembly checked out. There is a service bulletin about it. It is apparently harmless but bothered me. My dealer replaced the part under warranty and all is well. You might try viewing that thread and comparing your problems with the descriptions there.