Mysterious whine after driving in heavy freezing rain (recording)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Ethan Waldman, Dec 24, 2017.

  1. Ethan Waldman

    Ethan Waldman Junior Member

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    I had the unfortunate experience of driving through heavy rain / freezing rain /slush last night in my prius for about 1.5 hours.

    The prius with Micheline X-Ice Xi3 tires handled the roads like a champ. I got home and parked the car over night.

    The temps dropped considerably over night, and today when I drive the car, as soon as I start rolling, I hear a whine coming from the rear.

    It starts as soon as the car is rolling, but does not seem to be affected by speed- the pitch stays the same and doesn’t really intensify. After about 10 minutes of driving, the whine disappears and the car sounds normal.

    I can’t feel any strange vibrations or hesitations in the car.

    Here’s a recording of the whine after a few minutes of driving- it has become intermittent and then stops part way through the recording:

    Prius brake whine

    I have some theories, but I’m not a mechanic. Anyone care to weigh in?
     
  2. Ethan Waldman

    Ethan Waldman Junior Member

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    As a followup. I drove forward and backwards after letting the car cool down and it definitely sounds like the pad wear indicator is rubbing. Shouldn't it only be hitting when I apply the brakes?
     
  3. Raytheeagle

    Raytheeagle Senior Member

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    While now is not the best time to investigate, but when was the last brake inspection?

    How many miles on your Prius?

    Any history of accidents or damage?

    While not a mechanic, do you feel comfortable taking off a wheel and investigating?

    Keep us posted (y).
     
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  4. scona

    scona Active Member

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    Perhaps check the wheel wells for ice accumulation. Slush tends to pack in and then freeze, and can make odd sounds when rubbing up against the tires.
     
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  5. Ethan Waldman

    Ethan Waldman Junior Member

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    Been a while since I have inspected the brakes. My guess is I’m due for new rear pads and rotors. They were replaced at 50k miles, I’m currently at 90k

    90k in Vermont with lots of salt on the roads all winter.
    None
    Absolutely!



    Here’s another recording. Compared to other recordings I’ve listened to, I think it’s the wear indicator.

     
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  6. Raytheeagle

    Raytheeagle Senior Member

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    Definitely has a metal to metal sound to it.

    Definitely worth pulling off the wheels and checking it out;).

    2 sets of pads by 90 k miles:(? I would be checking the alignment of all components and increase the frequency of inspection as that is not normal.

    While I live in a non snowy area and have 170 k miles on the original pads with about 7 mm life left up front and 5-6 mm in the back, there are plenty of those in the salt belts that have longer pad life. Something to me doesn’t seem right:whistle:.

    Merry Christmas (y).
     
  7. Grit

    Grit Senior Member

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    I have that going on my Prius also. Sounds like the capiler pins need a fresh anti seize lube. One or both pin has seized and pad(s) are not fully disengaging from the rotor so the pad(s) is still making contact.

    Mine will come and go if I hit a bump, mash harder on the brakes or small pot holes on the road at fast speeds. Plan to reapply anti seize on my pins also.

    OR it could be that the warning low brake pad clips are making contact and that sound indicates replace them now.
     
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  8. Grit

    Grit Senior Member

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    Lucky you, les schab said I had 6 mm left on all 4s with 87k driven after rotation.
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Who did the replacement? A competent dealership, or? Even with a dealership, if they don't do a lot of Prius (3rd gen and onward, with rear disc brakes), they might miss this:

    The rear brakes are a poor design, in that it's absolute necessity to get the caliper piston rotated to a certain orientation, and easy as pie to not do it, and apart from a bit of vague reference in the Repair Manual, there's not much warning.

    If the piston is mis-oriented, symptoms will be pronounced drag (and maybe reduced mpg?), hot rear wheels, fast/uneven (extremely beveled) brake pad wear, scored rotors. With mis-oriented piston you're basically applying terrifically unbalanced pressure on the brake pad: pushing hard on the outer edge, and next to nothing on the inner edge.
     
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  10. Raytheeagle

    Raytheeagle Senior Member

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    Based on your above post, sounds like we have our first job at the next meet up(y)
     
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  11. Grit

    Grit Senior Member

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    Dam the next meet up needs to happen soon because mine has been going on since last month. But this needs to be done tomorrow or next week because paid holidays means no work next Monday and Tuesday so that's the only time I can get to it, unless the meet up is before the end of January.
     
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  12. Raytheeagle

    Raytheeagle Senior Member

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    I’m around and don’t have much going on :whistle:.

    Maybe you’ll find yourself down this way:).

    Let me know(y).
     
  13. Ethan Waldman

    Ethan Waldman Junior Member

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    I checked that, and the wheel wells are relatively clear of snow. Definitely no accumulation that's rubbing.

    I was also surprised how fast these rear pads/rotors started to wear after replacement...

    Definitely one or both!

    Now THIS is fascinating. I had the work done at a trusted local shop. Behind the Subaru Outback, Prius is a VERY common car here in Vermont, but I wouldn't be surprised if they didn't know this. As I mentioned above, I was surprised how quickly my rear rotors started to rust and wear (from the outside in toward the hub). I've never endeavored to do brakes myself, but now I'm wondering if I might be able to do a better job!

    Here's a photo of my drivers side rear brake taken the night I started this thread (yes, that's all salt from the roads on the wheels):
     

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  14. Raytheeagle

    Raytheeagle Senior Member

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    You know where the bar is now, and it’s not very high:(.

    If you have basic tools you can tackle this job:).

    What year is your prius? I ask because I’m not sure when they changed the back piston, but at the last Bay Area meet up there was a Prius v that did not have the alignment piston @Mendel Leisk describes. It might have been at the mid cycle refresh, or not at all. Something to be aware of though.

    Maybe Mendel will post a pic so you can see what he means;).

    Keep us posted (y).
     
  15. Ethan Waldman

    Ethan Waldman Junior Member

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    It's a 2011 Prius, so before the mid cycle refresh.

    Nuts about Bolts addresses the alignment piston in his rear brake video at 8:50:


    Regarding doing the job myself: I've watched a few videos and it looks pretty easy. I'd need to buy the caliper cube tool, but it's more that I don't have an indoor space to do the work, and also, here in vermont every metal piece gets so rusty it makes every job a lot harder. Here's a video of a guy doing 2010 prius brakes in upstate NY, and I have no doubt that mine will be just as bad or worse:

     
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  16. Raytheeagle

    Raytheeagle Senior Member

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    Just remember there is a jack point in the center of the rear in front of the spare tire area. The pinch welds are acceptable, but the back jack point gets both wheels at once;).

    That’s what I use and then some jack stands:).

    What area of Vermont are you located? There are some members in here that might be able to help if we have a better idea of your whereabouts ;).

    Good luck and keep us posted (y).
     
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  17. Ethan Waldman

    Ethan Waldman Junior Member

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    Burlington, VT, but I travel to Stowe area quite a bit. Anyone here?
     
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  18. Mendel Leisk

    Mendel Leisk Senior Member

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    upload_2017-12-26_7-25-8.png

    The above is an illustration in an excerpt from the Repair Manual, the section on front and rear brake maintenance (which I'll attach). It shows the correct orientation of piston, so that the stubby pin on back of inner pad falls between spokes.

    You want to get everything well seated in that orientation, to that end: when everything's assembled, do multiple brake pedal presses, take the car for a short test drive, gently apply brakes, and finally raise the rear once more, and test-spin the wheels. They won't be exactly free-spinning, due to disk brake slight drag, but they should easilly spin a revolution or two, with just a whisper of drag.

    Only then apply parking brake. I'm not 100 clear on this, but I'm pretty sure every application of parking brake attempts to rotate the piston, and that's basically the function of the pin locked between piston spokes, to prevent this. So delay parking brake use until the whole thing is well seated.

    The one caution with Prius brakes: disconnect the 12 volt negative cable at the outset, and reconnect only when everything is completely buttoned up. Keep in mind to keep the hatch from completely latching, say lay a glove over it, to prevent the need to crawl through the car to release hatch.
     

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  19. Raytheeagle

    Raytheeagle Senior Member

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    @m.wynn is within 3 hours and @mmmodem who just moved out there is within the same time span, but not sure of his setup .

    @m.wynn has a very nice setup right along the Hudson (you can see it in his avatar) and a great garage (which includes VXDiag capabilities):).
     
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  20. Mendel Leisk

    Mendel Leisk Senior Member

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    I don't even put safety stands on those #$*[email protected] pinch weld locations: they are flimsy knife edges. If you look at the supplied scissor jack, it's cradle is designed to cup around those pinch welds, the bearing point is actually behind, on the car body, and it's really not strong enough, I noted it dimpled slightly, when I used the scissor jack with a flat tire.

    I would raise the rear with a floor jack on the aforementioned rear-central jacking point (the little steel "inverted mesa", indicated in Owner's Manual), and then settle it onto safety stands, at the two reinforced plates zones, just inboard of the pinch weld loc's.

    Here I've circled the jacking point and the two safety stand points I use:

    upload_2017-12-26_8-1-13.png

    Also, maybe goes without saying: use kosher/heavy wheel chocks, fore and aft of each front wheel. And half-loosen rear wheel lug nuts prior to jacking.
     
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