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Wheel Bearings keep failing

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Parody, May 1, 2017.

  1. Parody

    Parody New Member

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    I have a 2008 Prius with 154k miles and have had to replace the front bearings 3x over the past 50k miles. My mechanic at Mavis says he's never seen this before and cannot figure out why it is happening. Left front just failed again after only 28k miles so he's replacing as in-warrarty (even though is out) for only labor ($50). Has anyone else experienced this problem?
     
  2. JC91006

    JC91006 Senior Member

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    Cheap bearings are known to fail. Next time replace with Timken or Toyota OEM

    SM-N900P ?
     
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  3. jessiejosco

    jessiejosco Member

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    Yes I am getting on average about 80,000 km (50,000 miles) out of the front wheel bearings on both of our Gen 2s. That is with OEM Toyota wheel bearings. For the last one I figured I would try a SKF wheel bearing since I figured they could not be much worse than the Toyota bearings. Although I got a SKF box the wheel bearing was identical to the OEM Toyota. Both were stamped with the same Japanese bearing manufacturer. The SKF was not made by SKF. I suspect you would get the same result if you ordered a Timken bearing.

    I took the last hub/bearing apart to see if you could just put in a new bearing and it is pretty obvious why they don't last very long. The outer races of the roller bearings are machined right into the soft hub, instead of having a pressed in hardened steel race. It looks like they have somehow surface hardened the hub to act as the race, but it is extremely thin and once it wears through you get deep pitting. Thought it might be happening because we are in the snow/rust belt and the bearings were getting dirt or salt in them, but the one I took apart did not look contaminated at all.

    So they are cheaply made and you can't replace the bearing. So instead of replacing a 30 dollar roller bearing you have to spend 150 bucks on a hub. Plus changing the hub is a real pain since the steel hub assembly corrodes itself to the aluminum yolk.
    Shame on Toyota. This is one of the cars major flaws.
     
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  4. R-P

    R-P Active Member

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    Same here, SKF VKBA 6924 according to box, but a Timkin or Nissin or ????? bearing inside identical to the one it replaced (will edit if I remember to look the old one up). Assuming the one I replaced was an original one that is... Replaced both sides in last 90000km (now odo at 220,000km, but not sure if they had been replaced before I bought the car, I have skimmed through all receipts but didn't notice a replacement).

    Bearing was 68€ (~75$) first time I ordered one and 88€ (iirc, little under 100$) a year later. But that's from a shop that works all through Europe and has very cheap but also strange prices (75€ for a Volvo enginemount in Germany, 150€ for EXACTLY THE SAME mount in the Netherlands, needless to say I ordered in Germany and had a friend forward it...).
     
  5. 05PreeUs

    05PreeUs Senior Member

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    Since most production bearings last well over 100k, and many over 200k, it strongly suggests installation error. When pressing the bearings into the knuckle, it is IMPERATIVE that it be pressed on only the OUTER race. If you press on the inner race, you have killed the bearing already.

    When replacing the BEARING, there are two steps that MUST be done correctly:
    1) Pressing the bearing INTO the knuckle by only the outer race
    2) Pressing the HUB into the bearing

    To accomplish these tasks, the mechanic needs the correct diameter mandrel to fit the outer diameter of the bearing for step 1. Then you need to draw the hub onto the bearing using a forcing screw inserted thru the bearing. Alternately, you *can* press the hub in, but the inner race of the bearing MUST be fully supported from the other side when doing so.
     
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  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I have not had to replace the bearings on any of the Prius that I've owned, most notably the 2004 which had logged 231K miles when I sold it earlier this year.

    I'm not sure whether the OP's mechanic is replacing the entire front hub, or just the bearing. However jessiejosco indicated that he has been replacing the front hubs with the correct Toyota-branded parts, and still has realized a short service life from those parts.
     
  7. bisco

    bisco cookie crumbler

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  8. ILuvMyPriusToo

    ILuvMyPriusToo Senior Member

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    I had to have my right front bearing replaced (somewhere around 65K, IIRC).

    Some folks have complained about poor engineering and small load bearing surfaces (I didn't inspect mine), but I also think road surfaces seem to be getting worse every year so things take a beating. :cry:
     
  9. 05PreeUs

    05PreeUs Senior Member

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    I would certainly attribute poor roads to earlier wheel bearing failures. Also, since the tires are the first springs on the car and the ONLY impact absorbing material between the wheel bearings and road hazards, high tire pressure could also be a factor.
     
  10. R-P

    R-P Active Member

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    I think you are discussing just the bearing and not the whole part as in my pic below? I'm having trouble following the above so not sure if I did it correctly... (but English is not my first language).

    The silver thing in my hand was what I replaced (~75$ (and ~100$ a year or two later)).
    [​IMG]


    The backside (which I am holding in my palm, but didn't photograph...) needs to be pressed in here (pic below) and I just did it by rotating each of the four bolts (see 4 holes arouns what we are sanding)and alternating between them after every half turn or so:
    [​IMG]
    This is where the aluminum and stainless steel form a bond for life, which is quite annoying when the bearing fails and needs to be removed...:ROFLMAO:

    Edit: found another pic of the sanding and the four boltholes:
    [​IMG]

    And somewhat of a pic of the old bearing that failed: I concentrated on the damaged surface, so no shot of the full part. The round thing in the top of the pic is one of the five fixed bolts that you put the actual wheel on (and tighten with a wheelnut).

    [​IMG]
    This caused a clear and distinct speed dependant whine.
     
    #10 R-P, May 10, 2017
    Last edited: May 10, 2017
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  11. Hjeff

    Hjeff Junior Member

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    I put rear bearings in my '08 5 years ago. Got them at Detroit Axle. Just ordered the fronts from Detroit Axle.
     
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  12. SFO

    SFO Senior Member

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    What kind of mileage have you put on the rear bearings after 7 years?

    How are the 2 year old front bearings holding up?
     
  13. TMR-JWAP

    TMR-JWAP Senior Member

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    Considering the hub is designed to be a pretty tight fit in the knuckle, perhaps the 'sanding' with a power tool is a bit extreme and that opening is no longer concentric?

    And old hubs are very easy to get out, even when 'bonded'.

    My method....obtain long bolts that are the same thread as the 4 bolts you remove from the back of the knuckle that fasten the hub to the knuckle. Insert them from behind the knuckle and thread them fully into the hub. They should be sticking out several inches from the back of the knuckle. Using a hammer, start gently tapping and if required progress to "Beat the F out of" those bolts as required, in the direction of the hub, to knock the hub out of the knuckle. Works like charm every time and only takes moments. Once hub is out, remove bolts and CAREFULLY clean the knuckle surfaces. Place bolts on shelf for next time.

    How is the metal ring that slides in from the back, where the ABS sensor looks through? Pretty sure that ring keeps contaminants out.
     
    #13 TMR-JWAP, Dec 27, 2021
    Last edited: Dec 27, 2021
  14. R-P

    R-P Active Member

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    Metal ring is OK. Somewhere else I already wrote I replaced one bearing yet again (probably the one in the pic above). And it was oxidised in place just as strong as the first time, so not too worried about making it concentric.
    Not having centre caps in the wheels might cause faster wear???

    The ABS sensor is a big issue though, so I'll write it down here again so I won't make the mistake of only remembering this when it is too late...

    Because it is aluminium, the thread holding the ABS sensor bolt is eaten away. Both my ABS sensors are literally holding on by a (single rotation of the) thread. I can probably rethread it, either with a helicoil or an M6 instead of the OEM M5 (didn't measure, so this is an estimate from memory). But you can only cut new thread BEFORE you mount the new bearing. And I only ever notice and remember there's little thread left when I am building it all together again (so AFTER I pressed in the bearing).

    Also: my Toyota dealer keeps pressing out the old bearings for free, leaving the work-shop floor covered in bearingballs... But I will try to follow (and understand) your explanation next time it is needed. BTW, just got passed 300000km (187500miles) and one wheel is on its 3rd (at least) and the other on its 2nd (at least) bearing. (Only owned the car half of its odometer reading, so would have to meticulously read through all workshop reports, but I doubt they were replaced before I got the car).
     
    #14 R-P, Dec 28, 2021
    Last edited: Dec 28, 2021
  15. helpmypriusplease

    helpmypriusplease Junior Member

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    Another vote for Detroit Axle parts here. My brother had one several years ago that would go thru the cheap autozone ones every 15k miles, finally bought good ones from them on ebay and had no more troubles with them.
     
  16. R-P

    R-P Active Member

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    First one was SKF brand iirc. Which is weird as I only know them from bearings, not from complete procucts like axle hubs but that might be a lack of product knowledge on my part.
    For Dutch people, SKF is considered an A+ brand afaik. But that didn't make it last any longer.