Lateral Runout Rear - 0.15mm (Or Why Rabestos is Shit)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by andreimontreal, Nov 9, 2020.

  1. andreimontreal

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    So Rockauto sent me new discs (Raybestos) when I replaced that messed up caliper batch. Only now I realized that a disc is rubbing (and NO it's not the caliper :p). I did a dial test on the dic, the hub flange. The hub/bearing assemlby is ok - I actually cleaned it properly with a dremel . The disc has 0.15mm difference from high to low (aka lateral runout) and it's "kissing"/rubbing ever so lightly against my brake pads. When I push the wheel it does about 3 turns then stops where it rubs. The disc gets a tiny bit warm. Can I drive like this? Should I buy one of those correction shims? I feel no shudder or anything.

    Btw the maximum runout in the repair manual is 0.15mm - I'm maxed out.

    The other side also does the same but much less I think. I can maybe 4 turns on the better side vs 3 on the "bad" side. Seems like a minor thing but it looks like it will wear my pads unevenly and the pad is starting to make marks into the disc.

    Andrei
     
  2. ChapmanF

    ChapmanF Senior Member

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    Have you tried it all five ways and gone for the lowest runout? That's usually suggested when an old rotor is going back on an old hub. It shouldn't be necessary for a new rotor on a new hub. New rotor on old hub? Well, worth a try.

    Were you cleaning up the hub around the studs with something like this?

    [​IMG]

    Ultimate recourse would be to shave the rotor a bit with an on-car brake lathe, which is Toyota's favorite kind: then the rotor ends up absolutely normal to the hub axis. (After that, of course, you pretty much have no choice but to match-mark it whenever you remove it, and put it back on the same way.)
     
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  3. andreimontreal

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    I was cleaning it with some tiny sandpaper drum, and a tiny wire wheel, and sandpaper. I was reading perfect near the hub, inside the bolts, and 0.01-0.02 mm at the edge of the flange (and that in a couple of spots). The hub seems to be near perfect.

    I switched the position once. I did a 180 thinking it would cancel things out - IF there was a hub issue. But instead I got the same wobble - touching at point say 0 degrees, then touching on the other face at point 180 degrees. So just like I measured: the disc is slanted, the hub is good.

    Ironically I found these instructions - and from Raybestos too (lol???) - about lateral runout. And just like they sayin p1, the disc wobles back and forth touching the brake pads intermittently - I can see it by eye as it happens too! And I'm starting to get weak traces of marks as the pads start to dig in.
     
  4. andreimontreal

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    So, you're saying: go to the deal to shave the discs? I suppose any mechanic should have that machine?
     
  5. sam spade 2

    sam spade 2 Senior Member

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    I think............
    You are within "spec".
    Disc brakes DO rub slightly and they DO get a little warm as a result.

    I would just drive it.
    The high spot should wear a bit quicker and the situation should get better with time.

    I am not a big fan of Rock Auto.
     
  6. tankyuong

    tankyuong Senior Member

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    Try using some spacers or washers
     
  7. andreimontreal

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    Me neither frankly, shit quality products :mad:. I know I'm within manual's spec - but it doesn't seem good to me honestly.

    Shims are 40-60 bucks cad at Napa. I might as well find a mechanic to shave my rotors like Chap suggests.

    Although! I'm thinking. If I buy the shim, theoretically, they are reusable for future messed up discs. So I might go to NAPA first.
     
  8. Kenny94945

    Kenny94945 Active Member

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    FWIW
    I would have a machine shop true the rotors.

    Even though you are within spec.
    I would also think the machine shop will be able to tell if the the center mounting area of the rotor or the rotor pad area is what is un-trued.
    Not sure how I would approach looking for hub run out.

    I wish you great luck.
     
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  9. ChapmanF

    ChapmanF Senior Member

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    I don't think I've ever heard of anybody using shims to correct brake rotor runout.

    That doesn't mean it can't just be a thing I've never heard of ... but it seems pretty out-of-the-ordinary.
     
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  10. andreimontreal

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    Yeah - could be a poor man's thing. Although, doesn't seem that inexpensive.

    I see Kenny's point above, with the shim I could end up way off the center, so I'm reverting back to your suggestion Chap.
     
  11. vvillovv

    vvillovv Senior Member

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    Another poor mans rountine is to just take a grinding wheel to the high spots and double check runout again.
    crude and tedious - some might call it something else ....
     
  12. ChapmanF

    ChapmanF Senior Member

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  13. pjksr02

    pjksr02 Active Member

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    I guess I got lucky with my Raybestos rear rotors and pads, on my 2010! Mine have been fine for over a year. I used their "hybrid" technology line (nothing to do with hybrid vehicles, of course)
     
  14. vvillovv

    vvillovv Senior Member

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    I posted some pics of my fronts after 35k. I thought the outside of the rotors were the issue when I double check for runout - that was before I saw the insides of the rotors. lol
    Rears look ok from the outside and I have gotten around to pulling them to check the insides yet.
    Oil change door missing plastic fastener | PriusChat
    I'm hopeful the OE's will clean up nice, but not countin on it.
     
  15. andreimontreal

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    To take a grinder to the disc, you need some rotation in that disc. And even like that getting it even functional won't be easy, it will be ripples, or a shimmed cut, because in some spots the hand will press further. I tried to get a piece of lumber flat with a belt sander for hardwood floor, and I had more than 0.5mm variations easily.
     
  16. vvillovv

    vvillovv Senior Member

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    for sure, usin a grinder on rotors ain't for everyone, could mark the hights and or lows and get as detailed as one likes. It's not even close to getting them turned no matter how one looks at it.
     
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