Short brake pad life / long rotor life

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by usando, Dec 25, 2019.

  1. usando

    usando Junior Member

    Joined:
    Dec 4, 2012
    6
    11
    0
    Location:
    Toronto, Canada
    Vehicle:
    2012 Prius
    Model:
    Touring
    60k miles. Had to do a vehicle inspection and I was surprised when the mechanic told me my brake pads needed to be changed:
    Rear: 99% worn
    Front: 90% worn

    I was skeptical as so many users here post about how they routinely get many more miles before changing their brakes. However, when I checked it was true. So I went ahead and changed the pads. Interesting thing was the rotors were barely worn.

    Rotor thickness:
    Front: 25.1mm (min 22)
    Rear: 10.5 mm (min 8.5)

    It's strange to me that the pads would wear out so quickly. I do drive mostly in the city and we do have harsh winters which means lots of salt. Still, did not expect to see such a short brake pad life span. Barely better than a conventional car.

    Anyway, just thought I would post in case someone else found the same thing.

    EDIT: I did check the caliper pins and they worked well enough so I don't think they were the cause of the short brake pad life.
     
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    8,533
    6,172
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Might be worth doing rotor temperature check for any dragging, now that things are back together.

    If it passes, then we have an unsolved mystery. If there are signs of dragging, then it's back to inspecting the calipers. Sometimes, reading PriusChat, you'd think the two slender slide pins are the only things that move or need inspecting.
     
  3. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    2,782
    1,258
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Interesting maybe but should not be surprising at all.
    That is the way it is SUPPOSED to work.
    Many vehicles go 200K miles or more and never need rotors.

    Seems like I remember that the pads on hybrids are thinner to start with because of expected lighter use.

    I would not be at all surprised at needing new pads at 60K on ANY vehicle.
     
    tankyuong and Mendel Leisk like this.
  4. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

    Joined:
    Oct 17, 2010
    38,401
    27,194
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Yeah that is a bit early. Maybe due to a lot of stop-and-go? And neglect? Was this the first time you had the brakes off? Toyota Canada recommends an in-depth "brake service" bi-yearly or or 32K kms, whichever comes first. I'm not strictly adhering to that, because we're quite low usage, but am doing them tri-yearly.

    See 2014 Toyota Canada Owner's Manual Supplement excerpt (attached), for maintenance schedule. Note: this is one year the schedule presentation was half-decent, so my preference.

    My last check with our 2010's brakes was in March of 2017, at 66K kms. At the time the front pads measured 7 mm remaining thickness. Just eyeballing them recently (not disassembled), they looked like they're around 6 mm now, at 85K kms.

    I get the sense that their wear rate accelerates a bit as they get thinner? Due to less material to dissipate heat? New pad thickness is 10 mm, and service liimit is 1 mm. Still, my bare mininum acceptable pad thickness would be 2 mm, and If I were to have the calipers off and be measuring even 3 mm, I'd be walking to Open Road Toyota for a replacement set.

    Ok, so taking my current wear rate (4 mm per 85k), and if I were to change with 3 mm remaining (that's a mere 1/8"), this is what I work out:

    upload_2019-12-25_8-52-25.png
    (yellow zone is a ratio equation, to extrapolate the wear rate)

    Say 150K kms, roughly 94K miles.

    There's some minor discrepancies in the above, see attachment for more info. Also, lots of good info on torque specs, how to check to check, lubes, reassembly tricks, in particular with the rears.

    Further on that, and to echo @ChapmanF : I would raise the rear, and verify the wheels are relatively free-spinning. With a good push they should rotate 2~3 revolutions before coming to a stop. If they don't, it's likely due to the caliper piston orientation being off.

    The piston has a raised 4-spoke pattern on it's face, that has to be like an "X" when reassembled, so that the stubby pin on back of inside brake pad is between the raised spokes on the piston face. See the attached for more info.

    Further, when it's all assembled, you want to avoid using the parking brake, pump the brake pedal multiple times, check for easy spin, lower the car, take a short test drive, apply/release the parking brake a few times, then raise the rear again, and verify the wheels continue to be easy spinning.

    One more thing: for a DIY'r doing Prius brakes, for safety, it's a good idea to disconnect the 12 volt negative cable before any disassembly, and only reconnect after everything is back together and you've pumped the brake pedal multiple times.
     
    #4 Mendel Leisk, Dec 25, 2019
    Last edited: Dec 25, 2019
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    86,361
    38,261
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    way too early, i'd be concerned
     
    kenoarto likes this.
  6. RMB

    RMB Senior Member

    Joined:
    Jun 21, 2016
    387
    608
    0
    Location:
    Oakland, CA
    Vehicle:
    2014 Prius
    Model:
    Three
    I wouldn’t be concerned. :ROFLMAO: Not my car Lol. J/K:p
    More have to do with driving conditions and style. oP mentioned stop and go city traffic so thats the answer. If it wasn’t for being a hybrid, pads would be gone at much faster rate.
     
    Raytheeagle likes this.
Loading...