Wth is up with my Rotors?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by priusrecon, Apr 16, 2022.

  1. priusrecon

    priusrecon Member

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    Anyone else have this happen with their Prius brake rotors?

    Back before I bought my Gen 2, I talked with a lot of owners I encountered about their experiences with their cars. To my surprise, I found most of them claimed to have never changed their brake rotors, or even their pads, even after having owned their cars for over 200,000 miles. I was always very skeptical about that point, but here were all these people insisting that it was so.

    In the years I've owned mine, I've not had that kind of luck with that, having changed mine several times in the few years I've owned the car. Granted, I drive mine a lot, but it's not wear that is the problem for me. It is the very heavy rusting out of the rotors so extremely quickly.

    Particularly gaulling is the last two years where I have had to change out my pads and rotors every year....that is I get one single year, only 12 months out of them....


    Look at these photos, these are the last two rotor changes I've made since the spring of 2020.....


    These were installed last spring ('21);....This is how they ended up this year (spring 2022);

    [​IMG]


    When installed last year (2021);

    [​IMG]


    And they replaced these from the year before (1 year on car by spring 2021);

    [​IMG]


    When those previous ones were fresh the year before (spring 2020);

    [​IMG]




    Now I know I live in NY, but so did all of the people I asked about their cars, so they were in the same conditions as I.

    I have owned a lot of Toyotas and other cars, and never gone through rotors this fast with any of them.

    Anybody else going through this?
     
  2. Another

    Another Senior Member

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    Corrosion on rotors is a result of not using the brakes much. Common occurrence.
     
  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    it is completely normal to see advanced rust on portions of a given disc brake rotor.

    the offset center area aka "the hat" tends to rust quite a lot, especially on the inside. This should be of no concern- once there's a good layer of rust on there, the reaction stops or slows to a rate that doesn't matter relative to the lifespan of a brake rotor.

    Meanwhile the area where the pads are pressed onto the sides of the disc should appear fairly polished, and that repeated friction should sweep that region clean such as the uppermost rotor in your 3rd photo.

    Looking at the second rotor- the one stacked on top in the 3rd photo, I don't see a clean sweep on that rotor face. That suggests to me that there is a problem with the associated caliper or its slide pins.

    To sum up, you may have some evidence of a deeper brake problem... but it isn't rust. The rust is just a symptom; the messenger.
     
  4. vvillovv

    vvillovv Senior Member

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    If your slide pin grease if black like mine was, you might want to clean the grease out of the slide pin holes with soapy hot water and Qtips than use some lithium soap based glycol grease (not to much either ) It new name is rubber grease G part # 08887-01206
    Brakes - the good the bad the ugly | PriusChat
    Mine airn't perfect yet, but I think I get closer to good enough after checking pads and loosening up slide pins while rotating tires or spring and fall. So far 30 k miles and only a bit of wear and rotor rust that I scuff off with 120 grit when needed.
     
  5. ChapmanF

    ChapmanF Senior Member

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    The brake pads can "sweep clean" rust that is quite fresh, say the flash rust after being parked in one night of wet weather.

    Rust that has not been swept clean, soon enough after it formed, eventually becomes grinding-wheel tough, and then it turns the tables, and reshapes the brake pads in its own image.

    [​IMG]
    [​IMG]
    [​IMG]

    This happens at both the central and outer rotor circumference. The ground-away pad edges no longer usefully brake against or clean the rotor, leaving just a progressively narrower and narrower band in the middle where the braking happens.

    I observed this on my Gen 1 in west-central Indiana, and Upstate NY uses a lot more salt.

    This is probably going to be a fact of life there that won't be easy to manage.

    As much as anything can help, it will probably help to drive the car more frequently, or at least to make a point of driving it soon after rainfall or damp weather.

    You can hear rusted rotors when you brake; there will be a rough grinding sound as you slow to a stop (around 7 MPH or below, when the friction brakes are brought back in). A quick way to get the flash rust scrubbed off is to make several stops in neutral (which takes regen out of the picture so the brakes have to do all the work). The stops don't have to be intense or from high speeds. I'll usually just shift to neutral for my first two or three regular stop signs on the way out of my neighborhood. Just keep repeating until the brakes sound good again.

    Also, inspect frequently. You're supposed to do that anyway, per the Warranty and Maintenance Guide. Many drivers neglect that, but Upstate NY is probably not a good place for that. More on that in this post.
     
  6. Tombukt2

    Tombukt2 Senior Member

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    Looks like this gold 09 made this near 200K on brake pads n slides . Pads crumble out of assembly. We replaced on purchase pads only. Everything silver n smooth . My rollas did none of this in Westchester in 77
     
  7. vvillovv

    vvillovv Senior Member

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    If you're a visual learner like I am the youtube channel this video came from can be really helpful, even when using aftermarket parts instead of OE. But if using Toyota parts it's even more informative.
     
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    I've seen a huge difference in rust buildup between original (OEM) discs and many aftermarkets.
    Looking at those discs, the first thing that popped in mind was there's an issue somewhere else than the disc
     
  9. alftoy

    alftoy Senior Member

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    If after you track down the issue, try coated rotors for rust prone areas, available from Rockauto or your local parts place.
     

    Attached Files:

  10. mr_guy_mann

    mr_guy_mann Senior Member

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    You live in the rust belt. Bad rotors are a fact of life there. Make sure the calipers and pins are clean and lubed when you put things together. Especially the caliper brackets under the stainless pad abutment shims (I scrape the rust off the brackets and coat with antiseize before installing the shims).

    As mentioned- drive the car regularly (a few times a week) and brake in neutral now and then to help "scrub" the rotors clean.

    That's about all you can do short of moving to a place without road or ocean salt.

    Posted via the PriusChat mobile app.