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Wheel noise -- bad bearings or something else?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by itrontz, Dec 7, 2021.

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  1. itrontz

    itrontz Junior Member

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    I recently had all brake pads and rotors replaced on my 2010 Prius (75,000 mi). When the mechanic took it for a test drive, he said it sounded like the bearings in both rear wheels were bad.

    I had my wife drive around while I sat in the back seat. There is indeed a rhythmic noise coming from each wheel when it gets above 35 mph, and it gets faster along with the speed of the car. It’s not a growl but it’s definitely noticeable. From the front seats you don’t hear any noise from the front wheels, only the back wheel noises.

    I jacked up the car a few inches with the car off and in park and on each rear tire there was no play when I tried to tug on the wheel, in neither the 3-9 or 6-12 positions. I also spun the wheels around and heard a metal-on-metal scraping noise, as well as a little rattling in the passenger side wheel.

    Sounds like the mechanic is right, but before I take it in for an $800 job, could it be anything else? Could the new brakes be causing any of these noises? The brakes seem to work fine.

    Below are links to videos of me spinning each wheel, and to a recording (ignore the video image) of what it sounds like from the back seat. It's a recording of a recording but you can still make out the rhythmic noise.

    Thanks for your input PC community!





     
    #1 itrontz, Dec 7, 2021
  2. Fred_H

    Fred_H Misoversimplifier

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    Hard to tell from a recording, but the scraping sound while spinning the wheels sounds like normal brake noise to me. During actual driving, the pads are normally pushed back a little by vibrations, so they don't rub as much as when spinning by hand.

    Unevenly worn tires can sound very much like bad wheel bearings. Even my experienced Toyota mechanic was not sure what it was, when I had noises. The only way to find out for sure before disassembling, was to swap the tires with new ones or used ones which are known to be good. In my case, it once turned out to be the tires, and another time it really was the bearings.

    Also could be flat spots or bulges on tires, balancing, out of round or wobbly rims, a bad shock absorber ...
     
    #2 Fred_H, Dec 8, 2021
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    The mechanic might have screwed up the rear caliper piston orientation when reassembling. It's very easy to do. There's a cross-pattern on the face of the piston that MUST be oriented like a letter X, and BE WELL SEATED THUS:

    upload_2021-12-8_9-26-13.png

    (Repair Manual extract attached)

    I would suggest you raise the rear and try spinning the wheels. There's normally "slight" drag, but they should easily spin 2~3 revolutions:

     

    Attached Files:

    #3 Mendel Leisk, Dec 8, 2021
  4. PriusCamper

    PriusCamper Senior Member

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    Yeah... I'd have the mechanic confirm their work based on Mendel's post... If the noise wasn't around before the mechanic worked on it I'd be reluctant to think it's the bearings until they get really bad and way noisier. And if you can get a noise from the wheels when car is jacked up I'd think that decreases the odds of it being a wheel bearing.
     
    #4 PriusCamper, Dec 8, 2021
  5. itrontz

    itrontz Junior Member

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    Thanks all...My wheel spins sound a lot like the one in Mendel's video, though there was also a slight rattling, as if something were loose, on the passenger side.

    I might just keep an ear on it and see if it gets worse. Car otherwise drives and brakes just fine. Tires look fine (they are regularly rotated)
     
    #5 itrontz, Dec 8, 2021
    Mendel Leisk likes this.
  6. Paladain55

    Paladain55 Active Member

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    I'm calling it now. Slide pins. My bet is they need grease.
     
    #6 Paladain55, Dec 10, 2021
    Paul E. Highway and PriusCamper like this.
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