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Brake pads rotation

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Former Member 68813, Apr 29, 2017.

  1. Former Member 68813

    Former Member 68813 Senior Member

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    Anyone doing it?
    I did some work on the car and inspected front brakes today and noticed that inner front pads had more wear compared to front outer pads (1-2 mm difference), but still very good at 85000+ miles. slide pins are greased regularly (about every 40,000 miles). i went ahead and rotated them after swapping the pad hardware. I've done it in 2 other toyota cars that had that uneven pad wear with no bad results.

    BTW, if car fob is not nearby and no opening driver's door, no need to disconnect 12V for simple brake work.
     
  2. JC91006

    JC91006 Senior Member

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    Until you accidentally open the door

    SM-N900P ?
     
  3. Former Member 68813

    Former Member 68813 Senior Member

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    i put duct tape across the door handle. easier than disconnecting the 12V.
     
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    It could be disconnecting 12 volt is overkill, as long as you're REAL careful about driver's door. I wonder if the car is more likely to detect excess pedal travel? Or would that only happen once the car is "on". In other words, if you push the piston in to accomodate new pads, and tromp the brake pedal multiple times to build up pressure (enter car through passenger side), will that keep the car "in the dark" as to what you've done? Maybe.

    Disconnecting the 12 volt is a hassle, and besides the usual post disconnect issues, lost radio presets and so forth, I've noticed the car seems to behave differently for the subsequent drive or two, doing odd rev-up, like it's recalibrating. Which it likely is.

    Back to original topic: is it ok to swap outer and inner pads? The shims are different, a bit. The inner pad has a handle, and the handle incorporates the "early warning" bit, IIRC.
     
  5. Former Member 68813

    Former Member 68813 Senior Member

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    you are right, if need to replace pads and push on pistons, better to disconnect 12V. but, not needed for just taking calipers off.
    yeah, i swapped the hardware including the warning metal clips (on each pad).
     
  6. Jimi1976

    Jimi1976 Active Member

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    My opinions, if anybody cares:

    a) It takes about 15 seconds to disconnect 12V battery. When working on brakes, just do it.

    B) uneven pad wear is indicative of a problem. "Rotating" them is not fixing the cause of said problem, but is simply a bandaid.

    I suspect a failing caliper, and/or bad rotor
     
  7. ChapmanF

    ChapmanF Senior Member

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    You should post a video of your technique.

    -Chap
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    It's quick, and maybe less wear and tear, if you disconnect neg cable at the body end.
     
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  9. Former Member 68813

    Former Member 68813 Senior Member

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    simply not true, at least regarding toyota cars.

    1. I have 2 more toyotas and each of them has the same pattern of uneven pad wear. the difference is not huge and you have to measure the thickness or compare them closely to see the difference.

    2. when i mentioned that on another car forum when i saw it the first time, some diligent members made measurements on their own cars and confirmed the phenomenon (other, less informed, just provided blanked opinion: it had to be abnormal).

    3. if you search internet, you find this:

    While performing a brake job, you may notice that one pad wore down faster than the other did. A small amount of uneven brake pad wear is to be expected from: What Is the Cause of Uneven Wear in Brake Pads? | eHow

    So, Jimi, where is your measurement of brake pad thickness to contribute to the discussion?
     
    #9 Former Member 68813, Apr 30, 2017
    Last edited: Apr 30, 2017
  10. Kenny94945

    Kenny94945 Active Member

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    Well I have never seen, heard or even considered rotating brake pads.

    Certainly with modern cars and brake wear warning lights one would have to consider the pin location.

    Even going back to repair cars in the 1960's I never encountered a brake pad rotation thought/ idea.

    Anything is possible though.
    Always good to think outside the box.
    FWIW In an emergency, I have heard of using JB weld as a pad material to protect the rotors.

    Thanks to OP for the post.
     
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  11. audiodave

    audiodave Active Member

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    Seen it on my old Chevy S10 Blazer. Sure it's the single piston design of the calipers. It's not ideal to rotate pads but certainly maximize life.

    Posted via the PriusChat mobile app.
     
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  12. Mendel Leisk

    Mendel Leisk Senior Member

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    Here's my measurements, first time:

    Saturday, March 15, 2014
    km: 43017
    * inspected front and rear brakes, pads disassembled and lubed, calipers pins relubed
    remaining thicknesses:
    front left outer:7.9
    front left inner:7.7
    front right outer:7.9
    front right inner:7.5
    rear left outer:7.7
    rear left inner:7.1
    rear right outer:7.2
    rear right inner:6.4

    My take: the inner pads are invariably a bit thinner, typically around 1/2 mm, which is really trivial. If everything is functioning normally, the calipers are near-free floating, the outer vs inner pad wear will be insigificant. Also, I don't see how you can transfer the wear indicator between the two pads. I would leave them as-is, with the wear indicator on the inside pad, serving as the "canary".
     
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  13. Former Member 68813

    Former Member 68813 Senior Member

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    simple, it's clipped on. it's on each front pad, on the upper side.
     
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    I stand corrected, both outer and inner pad have the copper handle. And the wear indicator? I musta been thinking Honda.

    upload_2017-4-30_10-17-32.png
     
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  15. working1

    working1 Active Member

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    Changed pads for the first time at 184k miles.

    Old pad measurements in mm:

    front pad new replacement: 9.5
    front left outer: 3.9
    front left inner: 5.6
    front right outer: 3.3
    front right inner: 5.8

    rear pad new replacement: 9.1
    rear left outer: 5.6
    rear left inner: 5.2
    rear right outer: 5.7
    rear right inner: 5.5

    Fairly balanced wear except the front outers. Based on this, I'll be increasing the frequency of relubing the front slider pins and only relube the rear pins every other time. I did rebuild the calipers so that should take those of the equation as the root cause going forward.