Brake rotor replacement needed when replacing pads?

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Fubar XIII, Sep 4, 2021.

  1. Fubar XIII

    Fubar XIII New Member

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    At 175k miles my rear pads are getting thin (need to look at the fronts again before I order).
    Problem is, I have been told that the rotors are "throw away" items that are meant to be replaced at the same time. This seems to contraindicate everything I know about rotors. I've only replaced one rotor ever (because the thin brake pad remnants broke off & the rivets gouged the rotor). Heck, half the time they don't even need to be "turned". I found nothing in the 800 page manual about it and have not called the dealer as yet.
    I've watched several YouTube videos on replacement - as I do before any procedure I've never done on a specific vehicle - but nothing mentioned there. The procedure is simple even when replacing rotors, maybe 15 mins per wheel start to finish and I have all the tools.
    I have no issues with the current rotors, no warping, pulsing, etc. and would like to save the dinero the rotors would cost if I can but would rather do both at the same time if required to save the time & sweat.
    So, I throw it to the cognescenti. :unsure:
     
  2. bisco

    bisco cookie crumbler

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    you only need to turn or replace the rotors if they are severly scored or out of true. it's a judgement call unless toyota has a spec
     
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  3. CooCooCaChoo

    CooCooCaChoo Active Member

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    Unless the rotors can't be turned to meet a minimum thickness, you would have to replace them. But, you should always turn rotors when replacing pads because it helps the pads wear evenly.
     
  4. ChapmanF

    ChapmanF Senior Member

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    The manual for an old Ford I had was memorable for the amount of down-to-earth advice about avoiding extra work ... it suggested not even turning the rotors, if there was nothing wrong with them that some 150 grit wetordry paper and a little elbow grease wouldn't fix up.
     
  5. alanclarkeau

    alanclarkeau Senior Member

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    Depends very much on how long you plan to hang onto the car. If I were to be planning just another year or so, I'd just pop some pads on. If I wanted to keep it to overtake Irv Gordon's 3 million+ miles on his VOLVO, then I'd change the rotors - and brakefluid.
     
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  6. sam spade 2

    sam spade 2 Senior Member

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    The original contention is BS.......and so is THIS.

    While rotors have gotten thinner over the years, there is NO reason to do ANYTHING to them unless they are visibly damaged or are below the minimum thickness.

    Not on any car. EVER.
     
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  7. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I would check (or have it done by a pro) the brake rotors against the specs shown in the Toyota Repair Manual. You’ll need a dial indicator with magnetic base and a 0-25 mm micrometer. Purchasing both (readily available say on Amazon) will be $100 USD or less. If the rotors meet spec, and are relatively uniform across the face, no runaway rust, there’s absolutely no reason to replace.

    more info in attached repair manual excerpt:
     

    Attached Files:

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  8. brenthon

    brenthon Junior Member

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    I think there's a required thickness to know if your rotors need to be replaced or not.
     
  9. vvillovv

    vvillovv Senior Member

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    Brakes - the good the bad the ugly | PriusChat

    Harbor Freight sells the stuff needed to do the runout test on the rotor less than half the estimate from Amazon. Micrometer besides, if you decide to go that route.
    If ya need a micrometer, most just go with new rotors anyway.
    The inside of the rotor might be in better shape than the outside, but you have to check both or be ready for a surprise if judging from just inspecting the outside.

    edit I like to use OEM, - but - even the dealers use aftermarket brake hardware many times, unless OEM is requested and doubles the price of the brake job.
    I do like the Toyota *NEW LEXUS TOYOTA OEM RUBBER GREASE 08887-01206 LITHIUM SOAP BASE GENUINE TRD | eBay
    especially if the caliper slide pin greece on the car is not red
    Good Luck with your project.
    @ChapmanF your post reminds me of a youtube that showed howto cleanup rotors with an air grinder.
    How far we've come since the 50's :LOL:
     
    #9 vvillovv, Oct 5, 2021
    Last edited: Oct 5, 2021
  10. ChapmanF

    ChapmanF Senior Member

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    I don't think I would take an air grinder within ten feet of a brake rotor. Probably isn't even a name for whatever shape the rotor would be after that.

    Now, if you have a rotor with some light glazing or rust, and you scrub it by hand with 150 wetordry, it won't have the glazing or the rust, and it will still be flat.
     
  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Rotor specs and check instruction are in the attached. A screen grab:

    38968ABD-0045-4EE3-B326-B878152FD5A5.jpeg
     

    Attached Files:

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  12. vvillovv

    vvillovv Senior Member

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    This U tube channel might be of interest
     
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  13. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Good video (gonna download), great summary of what the 30k or tri-yearly brake inspection should entail.

    You lubed caliper pins? What lube?
     
  14. vvillovv

    vvillovv Senior Member

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  15. Mendel Leisk

    Mendel Leisk Sand Pounder

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    The video you posted advocates for the caliper pins:

    Toyota Rubber Grease
    Toyota p/n: 08887-01206
    About $8 / 100g tube.

    (Around 4:08 in the video)

    McGeorge Toyota Parts link:

    https://toyotaparts.mcgeorgetoyota.com/oem-parts/toyota-rubber-g-100g-0888701206

    Not sure how that differs from the other Toyota product, the one you used.

    I use Sil-Glyde Brake Lubricant, but certain member here will go up one side of me and down the other about that. Also use on the pin boots. And for the pad-to-shim and shim-to-caliper points of contact: Permatex Anti-Seize. Contrary to the video I just put a thin/uniform coat on the inside of shim, then install. Similar application on the caliper contact points.
     
    #15 Mendel Leisk, Oct 5, 2021
    Last edited: Oct 5, 2021
  16. MPGboss

    MPGboss Junior Member

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    175k miles for a pad change is damn impressive!
     
  17. ChapmanF

    ChapmanF Senior Member

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    Yeah, the lithium soap based glycol grease is the 08887-01206. Top tube in this picture. The grease is red and clearish, and smells a bit like wet sweaters.

    The other greases shown are for other places on the brakes. Diagrams in the repair manual have different styles of arrow showing where to put the different kinds of grease. (I am not sure I've seen a Prius manual call for the -80609 grease anywhere.)

    If you buy a caliper repair rubber kit, it comes with a little packet of the correct red -01206 lithium glycol grease.

    If you buy a shim kit, it comes with the correct gray grease for the shims.

    [​IMG]
     
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