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When did your Prius need new brakes?

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by MattFL, Apr 10, 2022.

  1. lrisius

    lrisius Member

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    Thought I would add another data point. One of my rear brakes started making a dragging sound when being applied and released but the noise stopped with continued pressure so I assumed something was dragging or that possibly the wear indicator was kicking in. I was about due to lube the glide pins anyway. When I pulled the caliper I discovered that one pad was down to metal on metal and that the other side of the rotor was rusty so it hadn't been braking. When I worked on the other wheel, the pads had significant wear and I would have changed them even if not doing the other side. This was at just under 100k and I had lubed the pins at 50k. So not sure if I didn't lube the pins well enough or if something else happened. The front pads were in good shape. They're easily good for another 50k and maybe more.
     
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  2. douglasjre

    douglasjre Senior Member

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  3. jerrymildred

    jerrymildred Senior Member

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    And to add another data point, I've never had to replace them on a Prius. Highest mileage was about 175k.
     
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    See rear brake link in my signature. It is very easy to put the rear brakes back together with the piston misaligned, and it'll cause those symptoms.
     
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  5. paprius4030

    paprius4030 My first Prius

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    I've had 5 Prius non ever needed brakes. My last Prius had 166k mi. on it and at it's last oil change at 165k. the dealer said it had 3mm. left. If it was a regular car he said you should think about getting the brakes done but on a Prius I probably had at least another 10k. mi. to go. And that was a Toyota dealer that said that.
     
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    One way to make sure your Prius go brakes go a long way, is to not go a long way between brake services. Toyota recommends tri-yearly or 30K miles for service.
     
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  7. lrisius

    lrisius Member

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    Thanks for this info. I had never realized some brakes required this alignment. So I opened mine up again to check and my piston is smooth all the way around. No spots to align the pins on the pads into. The pads did have the pins (or tabs). Could there be a difference in model/years? Mine is a 2015 Prius v Level 3 and this was the rear brakes. I should have taken a picture of my pistons but didn't think of it till I had it closed back up.
     
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  8. ChapmanF

    ChapmanF Senior Member

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    The pistons with the notches are used on the Gen 3 liftback, which has rear disc-brake calipers that double as the parking brakes. The notches are needed to prevent the piston from spinning on the threaded parking brake strut.

    If you have a Prius v wagon, I believe you have disc brakes with a top-hat shaped rotor, where the parking brake is a separate set of brake shoes underneath. So your caliper piston does not need notches.
     
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  9. lrisius

    lrisius Member

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    Thanks. The rotor is top-hat shaped and I assume have a set of shoes for the parking brake. Looks like most of the rear disc cars I have worked on in the past.
     
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  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Woops, major mess-up: you have the Prius v, which has a mini-drum brake in the rear, different than the reg Prius 3rd gen in that regard. Disregard what I said, and sorry.
     
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  11. lrisius

    lrisius Member

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    No worries. I really appreciate all the help I get from you and your posts.
     
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  12. dyun1dyun1

    dyun1dyun1 Member

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    I'm at 150k mostly highway miles and have less than half of my pads left.

    SM-G998U ?
     
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  13. DogDaze

    DogDaze Member

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    I have a 2012 PriusV and put $1000 into a complete brake job at the dealership ~2 years ago... we live in NE Ohio, so do contend with the winter road salt. I'll admit that I've been rather lazy, but noticed last week that I had a fair amount of brake dust on the left front wheel after a 50 mile trip back home at highway speeds.. I also couldn't believe how HOT the entire wheel was. So, I took them apart on Saturday and found the top slide pin mostly "stuck" and had to tap it loose to get it out and clean it up.. re-greased the slide pins on both front etc. Cleaned up the caliper piston.. I was expecting the pads to be smoked, but they are fine.. So, I put it back together and drove it that same 100 mile round trip yesterday... thinking all was fine, but upon return home I still have (light) break dust.. (again) and yes, a hot wheel again.

    I did have to stop abruptly at one point when the car in front of me on a causeway abruptly stopped.. (~40mph to 0) for NO apparent reason there was NO traffic in front of him.. he apparently thought he was in the wrong lane and then decided he wasn't <sigh>
    But that shouldn't have caused any issues..

    I tend to think the caliper is in need of replacement.. and I'm not one to like to bleed brakes..
    has anyone changed the calipers yet? Are there rebuild kits or just change the entire thing?
    Has anyone looked into a power coated or better set of calipers for the PriusV?

    Edit: I only have 118k on this car... and that $1000 brake job was not the first set of brakes it had.
    I bought it used from a non-Toyota dealership.. and they put brakes on it before I bought it.. but they didn't last very long.. This set since my $1000 brake overhaul have been perfect till now, but maybe only ~30k miles... as noted the front pads look fine.. so, they have been working well until now.

    Thanks in Advance..
     
    #33 DogDaze, Jul 11, 2022
    Last edited: Jul 11, 2022
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    Probably the dealership didn’t touch the pins.
     
  15. DogDaze

    DogDaze Member

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    Hi Mendel,

    Thank you for your note... and I tend to agree, but I free'd them up now and still getting brake dust.... I tend to think the caliper might not be traveling back all the way now.. not by itself anyways..
     
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  16. ChapmanF

    ChapmanF Senior Member

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    Yes, there's a rebuild kit, it's inexpensive, contains all the rubber and miscellaneous small bits you need to rebuild both front calipers.

    And yes, you're absolutely right that the pins are not remotely the only parts of the brakes that can contribute to dragging. I'm sometimes surprised how much they are talked about here, compared to how little attention to the rest of the system. Personally, I think so far I've never worked on a Prius dragging brake that turned out to be caused by the pins.

    If you take the caliper off and find it cleanable and rebuildable (no bad rust or scoring of bore, etc.), I think rebuilding it is a better bet than trying to find some "better set of calipers" somewhere. The Toyota calipers are quite good, and as I discovered, aftermarket options can be made to look really good at first sight and not have the same quality.

    I tend to agree with this guy about "getting the proper caliper on your car. There's a good chance those are the calipers you have on your car, you just have to treat them properly."

    One of the ways I discovered an aftermarket caliper can fail (right out of the box!) is to not have any piston return. The piston is supposed to stretch its rubber seal (the one you can't see inside the bore, not the rubber bellows you can see) a tiny bit, so the seal pulls the piston back by a small distance (good Prius Gen 1 calipers were about 0.3 mm) when you're done braking. Without that, they'll drag.

    [​IMG]

    It's a simple idea, but depends on getting the composition of the rubber seal and the texture of the piston surface just right, which Toyota does, and in some reman with mixed-n-matched rubber and shiny polished pistons, it's a crapshoot.

    In this post, you can see how I measured the piston return. After that experience I had, I made a resolution to always measure that on the bench to catch a problem before spending the time to put a caliper on the car.

    That thread also mentions the option of getting a reman caliper from Toyota. Those really are restored to Toyota quality. You can find them by looking up your regular caliper part number, then searching for it with -84 tacked on at the end. Not all parts have -84 versions, and they might not always be available. (Also, as that thread shows, a -84 version might not include all the same pieces that the part number without -84 includes, so you have to watch for that.)
     
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  17. DogDaze

    DogDaze Member

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    Thank you for your note and the detailed information. I did not try stepping on the brake pedal when I had the caliper off.. I wasn't certain as to how far it would move... this is helpful information.. and I heed your advise on anything aftermarket. I think I'm gonna call the dealership and just schedule mine in.. as I don't have the luxury of the time to DIY (this time around) Currently have a family loss (my Dad) so need to focus on that, but have the car ready for the trip for his celebration. Thank You.. -j
     
  18. ChapmanF

    ChapmanF Senior Member

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    I hope you did not take anything I wrote as suggesting to step on the brake pedal with the caliper off.

    Don't do that. You will find your caliper and piston in two different places, and your brake fluid on the floor.
     
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  19. DogDaze

    DogDaze Member

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    HA!! I kinda thought that might be the case... and so, I appreciate that you mentioned it.. & yes, glad that I didn't do that. =)
     
  20. ChapmanF

    ChapmanF Senior Member

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    ... even if you only pressed the pedal lightly. The ECU will compute a target braking pressure and try to reach it by any means necessary, which only can happen if there's something the piston can press against.

    Also, where I described (in that other post) measuring the piston return, I was doing that on the bench, using only light puffs of air. I think a suitable on-car method could be to use light puffs of air into a hose attached to the bleeder (with enough fluid in the hose that the air doesn't enter the caliper), but I've yet to try that for real.

    What doesn't work is using the brake pedal to test piston return. At the forces involved in braking, metals, and whatever you use to block off the piston for the test, are elastic, and your dial indicator will end up showing you that, more than it shows the actual piston return.
     
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