On changing the brake pads in my 2010.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Boffin, May 7, 2019.

  1. Boffin

    Boffin Member

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    While the Prius, with it's excellent regenerative braking, is known to go
    through brakes at about half the rate of a normal car, after 125,000 miles
    in my 2010, it was time. My front pads were worn to about 25% of new, and
    the rear pads to around 35%.

    I bought Wagner pads from Rock Auto, as well as the Lisle rear brake piston
    retraction too. In theory, you can simply use a pair of needle nosed vice grips,
    but I'm glad I bought that tool (~$10.00). You'll also need a silicone based
    grease. Regular grease won't do. Make sure you have the silicone grease. I'm
    also tacitly assuming that you have the other automotive tools that most DIYers
    acquire over the years.

    Next I carefully watched NutzAboutBoltz's excellent videos about changing the
    brakes in a 3rd gen Prius. Twice. Then I watched those from 1Aauto. This is
    helpful, as most of us change our brakes about every decade or so, and the
    memory of the job fades. The devil is in the details, and it's nice to have them
    fresh in your mind.

    Don't forget to disconnect your 12v battery *before* starting this job! Note
    also that you make sure your car is unlocked when you do this. You'll find
    that when you reconnect, you'll have to do it from the folded down back
    seats. Or you could just leave the hatch open as you work.

    The front 14mm bolts came out nicely. I used a box end 14 mm and banged it with
    a hammer to break it loose. It's only torqued to 25 ft-lbs, but after almost a
    decade of exposure, it takes more grunt than that to get them off. The 17mm
    were even worse, I needed my breaker bar and cheater to break them.

    After 9 years and 125K miles my rotors were rusted to the wheel hub. I needed
    to use the 2 bolt holes in the rotors and some bolts I had in my old bolt
    collection to pry them out. The rotors themselves were not badly worn, so
    I did not change them. I did, however, clean up the rust and paint it over
    with anti-size. Those rotors will never stick again!

    <Related story>
    I learned of anti-size 35 years ago from a diesel mechanic. He worked on city
    buses, and they used anti-seize on virtually all fasteners not already bathed
    in oil. They knew that all of their work would eventually return to them, and
    they hated to have to deal with rusted bolts. When a "new" bus came in for its
    first overhaul, no one really wanted to work on it, as it was guaranteed to be a
    real pain, fighting the rust.
    </Related story>

    The caliper slider bolts on my front brakes were starting to not slide well. I
    took them apart, cleaned them up and regreased them with my silicone grease. It
    helps to have a nice, bench mounted, vice to pull the slider bolts out if
    they're badly stuck. A good one (the ones on my rear brakes, for example) comes
    out with a good tug using your fingers only.

    The hardware that the pads slide in was dirty, but very easy to clean and re
    lube, so I didn't bother changing them out.

    As per NutzAboutBoltz, I used anti-sieze to lubricate the pathways where the
    pads slide. I too have found that it sticks around a bit longer than regular
    grease.

    On the rear brakes, the official Toyota service manual, and several on line
    tutorials recommend disconnecting the parking brake cable. Again, as per
    NutzAboutBolz, I did not. Much easier!

    Retracting the rear brake pistons is a bit of a chore. Initially I thought one
    simply screwed them back into the piston. No. You have to push hard and screw
    it into the piston with the cubic tool (the face with the 4 nubbins on it
    seems to work best). Remember to leave an open slot facing the center of the
    wheel for the post at the bottom of the brake pad.

    The pros who do this for a living seem to be able to do it quickly. Most YouTube
    tutorials are under 20 minutes. Ummm, for us DIYers, it's not that fast. I
    spent in excess of 4 hours on this. I'd reinstall things wrong, and have to do
    it over, misplace a tool, etc. Plan on burning an entire Saturday for this. When
    you're done, clean up and go out to dinner! You can afford it now, not having to
    have paid the pro mechanic, or worse, the stealer to do it!
     
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  2. padroo

    padroo Senior Member

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    Thanks for the good write up. The YouTuber's have something on their side called edit that makes them look fast and good. :)
     
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  3. gliderman

    gliderman Active Member

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    Good write up. I never disconnected the battery. I just rolled down the windows and left my fob in the house. All worked well when I was done. Did all four at the same time. Could have gone another 100K on the brakes. LOL. I love my Prius!
     
  4. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Toyota USA, inline with most manufacturers, recommends a full brake service, regardless of pad thikness, every 3 year or 30K miles, whichever comes first. Too many owners seem to conflate brake job with pad replacement. Better late than never though, thanks for the write up. (y)

    Toyota makes a specific grease for the pins and boots. I've been using Sil-Glyde Brake Lubricant for years, on various cars, no problems. For contact between pad backs, and shims, and calipers, Permatex Anti-Seize is what I've been using. Apply it to the part that's going to lay atop the other, just a thin layer. That way you get it just where needed. I would leave the pad ears (the two nubs at the end) clean, they're too exposed, and grease would attract grit.

    I would play it safe, disconnect the 12 volt. It only takes one lapse, opening the driver's door while caliper is off.

    And just before reconnecting, tromp the brake pedal multiple times. Don't be too quick to apply the parking brake either. Start it up, take a short test drive, and upon your return apply/release the parking brake several times. Then raise the rear (chock front wheels) and check that both wheels are spinning fairly freely, above to spin 2~3 revolutions with a good push.

    If they're sticking, it's likely the rear caliper has managed to rotate, needs to repositioned and reseated.
     

    Attached Files:

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  5. ChapmanF

    ChapmanF Senior Member

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    It's good to mention that Toyota specifies a specific type of grease there. It would be even better (especially given the OP's emphasis on silicone) to briefly mention just two more things about the specified grease:

    • It has an actual name and part number that are not shrouded in secrecy, and
    • it is not a silicone.

    [​IMG]
    [​IMG]

    If you buy the Toyota rubber parts kit, there's a little packet of the right grease included.

    Testimonials about other products, Sil-glyde or whatever (which is a silicone) are all very well, as long as readers are clearly informed what the specified grease is, and that the alternative stuff ain't that. It's only fair to be up front about it.

    Agreed here. Toyota recommends nothing on those parts. When you buy those hardware bits (the "fitting kit", as it's called), they come with a dry, Teflon-like coating that is very slippery without attracting grit. It eventually deteriorates.
     
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  6. CR94

    CR94 Senior Member

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    'Scuse my ignorance, but that's the part I do not understand. Why would the system try to send pressure to the caliper, as long as the brake pedal is not touched? The pump runs when you open the door only to maintain pressure in the accumulator, not to apply brakes, in my understanding.
     
  7. gliderman

    gliderman Active Member

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    The pump did not run when I opened the door. I think it only runs when the fob is in proximity and open the door. I keep my fob in the house when I work on the car.
     
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  8. ChapmanF

    ChapmanF Senior Member

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    Two different things get mixed up sometimes.

    When you open the driver door after the car has been off for a while, that will trigger the pump to run. Just as you say, that only pumps up pressure in the accumulator, and does not send any pressure to the wheel cylinders.

    Now try something else: after parking the car and shutting it off, just sit there quietly in the driver's seat for a few minutes. A few minutes after the car was shut off, you will hear some clicking and squirting noises from the driver's side of the firewall (you may also hear the pump run again, depending on the pressure). That is a self-test of the braking system, and that does send pressure down the brake lines (the valve clicks and fluid-squirting noises you hear). That would be a bad time to have a caliper apart (or, worse, your fingers in it).

    As far as I know, that's the only time that self-test happens: just once, a few minutes after the car has been parked and turned off, every time. I'm pretty sure, if you wait for that before starting work, it won't sneak up and surprise you again. And just opening the door and triggering the pump-up will not give you a problem.

    But sometimes what's written in the forum isn't careful to distinguish those two different things.
     
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  9. gliderman

    gliderman Active Member

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    Thanks for the write up ChapmanF. I have found that if the FOB is not present, the pump does not activate when the door is opened, or even pressing the brake pedal. I replaced all four brakes and purged/replaced the fluid and the pump never came on. YMMV
     
  10. CR94

    CR94 Senior Member

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    Yep! I've wondered about those strange post-shutdown thumps ever since my first test ride in a Prius. So I can lube my slide pins without disconnecting the battery or worrying the piston will suddenly be ejected from the caliper?

    Thanks!
     
    #10 CR94, May 8, 2019
    Last edited: May 8, 2019
  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I think I'll continue to disconnect the battery, just in case.
     
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  12. ChapmanF

    ChapmanF Senior Member

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    Welp, what I'll say is I think that self-test only happens the once per drive cycle, a few minutes after shutdown. I've never noticed it happen any other time. So I think you probably won't have trouble if you've waited for that to happen before diving in.

    I don't think anything in the manuals promises that (or goes into much detail about it at all, really), so in your own approach you'll probably be figuring in your own level of comfort with risk, and how comfortable you are relying on what I think.

    You can avoid the risk by unhooking the battery. :)
     
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  13. Boffin

    Boffin Member

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    I've always wondered about those clicks that occurred several minutes after I shut the car down. A brake system self test. Thanks, ChapmanF for the data!
     
  14. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Tested that this morning. fob not on me, well away from the car: opened the driver's door, the pump still runs.
     
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  15. gliderman

    gliderman Active Member

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    Thanks Mendel! I did not experience the pump coming on opening and closing the door when I changed my brakes. And we pumped and flushed the old fluid out with new fluid and the pump never came on until I pressed the start button. Maybe because I had already driven the vehicle and the pressure was still up. Strange creature these Prius. YMMV
     
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  16. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Yeah it's not difficult to test for yourself. Definitely do this before pulling off a caliper.

    I like the car to be comatose, till the brakes are completely back together, and the brake pedal's been pumped multiple times, to take out any excess travel.

    Maybe overkill, don't care, lol.
     
  17. Colm01

    Colm01 Member

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    Mendel, I had the same thing happen to me while I was replacing the control arms and front wheel bearings. I opened the door without the FOB to get some paperwork and the pump came on. It pushed out the caliper pistons. I didn't realize it until I went to put the calipers back on. The loaded caliper wouldn't fit back on the rotor. I had to collapse the caliper and it all went back together. Could have been worse.
     
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  18. ChapmanF

    ChapmanF Senior Member

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    As covered a few posts up, simply pumping up the accumulator won't have been what pushed any pistons out. The accumulator is not the pistons.

    If the system later conducted a self test, that could be what did it.
     
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  19. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Whatever does it, disconnecting the neg battery cable stops it.
     
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  20. Grit

    Grit Senior Member

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    How was this done?
     
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