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Wheel Bearing Replaced - 20 to 25% Drop in MPG?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by KnightofNi1, Sep 7, 2018.

  1. KnightofNi1

    KnightofNi1 New Member

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    I recently purchased a used 2004 Prius and have been doing some minor repairs on the weekends.

    While driving the other week I started to hear a slight grinding sound from the front passenger side. It sounded like maybe the caliper and/or slider pins weren't functioning correctly which didnt surprise me as the rotors looked like garbage. Since I was down there anyway and the rear drums looked like garbage too I replaced all pads, rotors, and drums. Though obviously not new everything else looked and functioned okay. Took for a test drive and all worked fine except I could still hear the grinding sound.

    I suspected it was the wheel bearing but having never replaced one before I took it to my local mechanic to do it. He showed me the hub after he replaced it and it was all torn up. I'm not sure how it functioned at all frankly. Said he even had to "nick it with the torch" to get it off since it was fused on.

    Anyway, my mpg was normal for me after the brake replacement for the 75 or so miles I drove before I could get the wheel bearing replaced but now I have dropped 20 to 25% off of that. Is that normal? Does it take time to settle in so to speak?
     
  2. bisco

    bisco cookie crumbler

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    no. jack up the car and see if the wheel spins freely.
     
  3. KnightofNi1

    KnightofNi1 New Member

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    Just because I want to know what my Sunday is possibly going to look like I went out and jacked the car around midnight.

    How hard is it supposed to be to spin the wheels when the whole front end is up? I could spin both front wheels but it took more effort than I was expecting.

    Just because I had the jack out I did the back end too. Rear passenger side spun freely as expected but the rear diver side was different. I could spin it easily about 3/4 of the way and then all of a sudden I could hear rubbing and the tire came to a halt. I spun it hard the 2nd time and it slowed WAY down after about 3/4 around and by time it hit that patch again on the 2nd revolution it stopped.

    I'm baffled by that because I did the spin test after doing the rear brakes and both worked. Plus, when I noticed the drop in MPG I went out driving for a while and made sure to use my brakes a lot. When I hit the driveway I got out and immediately hit all drums, rotors, pads, etc with a temperature gun but saw no noticeable difference between the 4.

    That definitely explains part of it but would that cause that big of a difference?
     
  4. bisco

    bisco cookie crumbler

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    it's hard to say. if both front wheels feel the same, they are probably fine. you'll have to open up the rear wheel to see what is rubbing. once it is fixed, you can measure mpg again.
     
  5. bisco

    bisco cookie crumbler

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    why wheel was the bearing replaced on?