Seized rear left caliper

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by 2010PriusMon, Nov 25, 2019.

  1. 2010PriusMon

    2010PriusMon New Member

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    Over the summer, noticed a sort of "card in bike spoke" type noise coming from the driver's side. Brought it to my usual mechanic spot and they said they could hear it, but couldn't see anything, could be transmission related. Right after, it magically stopped happening so they said it's probably good unless it comes back.

    The last few weeks, I noticed my brake occasionally squeaking on the driver's side at slow speeds and when coming to a stop. I took it in, and turns out my left caliper was seized and wore down the pad to metal and screwed up the rotor.

    This is now going to be a $1200 (canadian) repair job for both calipers, left rotor and pads. I'm at around 70k kms (44k miles) and have had the car since it was new. This seems like a low amount for this type of issue, but I do drive in Toronto winters and don't drive my car a tonne in general, as you can see based on the mileage. Is this something that sounds right, and is the amount for the repair seem reasonable? I'm somewhat mechanically inclined but don't have anywhere to work on it, nor do I really want to be driving the car in this condition. I'm also wondering if the start of this was when I originally brought it in for the first noise, but they just didnt noticed, so I've driving with a stuck caliper for months, now having caused more damage.

    Also, is there anything else I should be getting done considering I've had the car 10 years? I've had some "maintenance" done at a dealership when it was still in warranty maybe 4-5 years ago, and obviously . Feel like there's probably a bunch of stuff to do based on time, even though my mileage is still relatively low.
     
  2. Siward

    Siward Member

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    I guess it is a coincidence. I had rear left brake problems too. I am also in Toronto. I just replaced my RL caliper on my 172000km 2012 Prius last month, but not because it was seized. I had a lot of uneven brake wear due to what I suspect was a bad caliper mounting bracket because the upper hardware was always loose. It cost me less to simply replace the whole caliper with an aftermarket one. There was also someone from Montreal who replaced his seized caliper as well last week:
    Rear Left Prius Brake Caliper Seized | PriusChat

    I replaced the rear left caliper for a lot less with aftermarket parts from RockAuto. Prices on RockAuto have gone up a lot since then.
    1) Raybestos Element3 Caliper (RL) $120
    2) Centric Premium Coated Rear Rotor $45
    3) Wagner Thermoquiet Pads $35
    4) Shipping was about $30, but I bought other stuff and I picked it up at the border on my way to Ottawa
    5) I paid the mechanic that I bought my car from $100 labour to install one entire brake corner.

    So, I guess I paid around $330 in total to have the entire rear left brake replaced. There is really no need to replace both calipers if only one is broken. My Toyota dealership in Vaughan/Etobicoke quoted me around $250 for an OEM rear caliper assembly or $160 for a caliper mounting bracket.

    There are a lot of Toyota enthusiasts here that would recommend OEM, but I would use aftermarket until proven otherwise. The OEM caliper pricing was just too much for me. I would like to give you a review of my aftermarket caliper, but I haven't driven my Prius in the last month.

    Going forward the recommendation is to follow maintenance schedule in the Toyota manual. Everything else, I would recommend replacing only if it is broken. The only thing not in the manual is the transmission fluid replacement which is up for debate.
     
    #2 Siward, Nov 25, 2019
    Last edited: Nov 25, 2019
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  3. Classic Car Guy

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    Interesting. I had a situation on my 2007 front passenger wheel was like an intermittent rolling noise. Pulled out the wheel and I found the brake caliper lower housing bolt (the hub) was loose! That was a dangerous situation especially if that was the upper side of the hub would have a vehicle trip result. I took off the upper and lower on both sides, put a lock tight, torque it.
    I have worked on a lot of cars and this is the first time I've seen this happen. I wonder if this was a random phenomenon but it was a saved by the bell.
     
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  4. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Do you get the brakes regularly serviced? It's good to pull off the calipers, at least every 3 years or 48K kms (whichever comes first).

    Disassemble and clean the pads and shims, then reassemble with fresh anti-seize at all faying surfaces. Apply the anti-seize (sparingly) to the smaller of two items, then reassemble it on the larger. Also apply a little anti-seize on the caliper fingers, and a slight amount, just on the rim of the piston.

    Pull the caliper glide pins, clean and relube them with something like Sil-Glyde Brake Lubricant, push them back in, ensure they're moving easy, and smear a little of the grease sparingly on the boots.

    Reassemble and torque the bolts.

    One additional caution with the rears: make sure when reassembling that the 4-spoke pattern on the piston face is oriented like an "X". This is crucial: you need to ensure that the stubby pin on the back of the piston-side brake pad is in between the raised spokes. Assemble thus, torque the bolts, (don't apply parking brake), but push the regular brake pedal multiple times, to help seat the pads solidly.

    Reconnect the 12 volt neg cable (it should be disconnected at the outset), lower the car, take a short test drive being very easy on the brakes, return, apply/release the parking brake a few times, raise the rear, and verify the wheels are relatively free spinning. Like this:



    Repair Manual info in the attached.
     
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  5. scona

    scona Active Member

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    You have good advice from the replies, I would advise shopping around for a better repair estimate . I did a similar job on a 2010 rear wheel for less than $400.00 in parts.
     
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  6. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Just the pads/shims are around $125 CDN, front or rear, up here.
     
  7. Pseudonymm

    Pseudonymm New Member

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    Is the caliper really the broken part here, or are the pads themselves seized up? As mentioned, the rear brakes require regular inspection in salty environments. I had to replace rear pads and rotors at about 60k for reasons similar to yours. The pads tend to rust and jam and not retract. They are getting sticky again at 100k (uneven wear, dragging), but I still don't think there's anything wrong with the caliper pistons. If your mechanic tried to push back the pistons and couldn't, then, yes, maybe they are toast.
     
  8. 2010PriusMon

    2010PriusMon New Member

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    Thanks everyone. Due to time constraints and not having any other vehicle to pick-up parts I ended up just getting it done. Called around to a couple other places and they were still quite a bit cheaper. Had I had time/a way to pick-up my own parts that would've been the biggest money saver (100 for pads, 150 for 2x rotors, calipers 250 each is what I paid), labor was very reasonable. I will definitely keep up with the brake inspections from now on since I regularly drive in winter and don't drive a lot in summer, seems like a recipe for seizing.

    I'll likely just get all my fluids/bearings checked after winter as it's been 10 years with only a couple dealership maintenance checks (when in warranty) and one at my usual mechanics, can hopefully avoid a bigger job like this in the future. Appreciate all the responses!

    The one thing I'm mostly annoyed about is that they didn't find anything amiss after bringing it in for the initial noise in the summer. It may not have saved me any work though if it was the same issue and the crooked pad had already messed up the rotor.
     
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  9. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Mostly just editorial: the rear caliper pistons screw in.
     
  10. Pseudonymm

    Pseudonymm New Member

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    If they screw in, do they screw back out with every depression of the brake pedal? The inner workings always being hidden, I have difficulty imagining how the two motions are coupled--twisting and retracting. It can't really be threaded, can it? Or does that work because in service it only needs to extend a tiny amount?

    Edit: Oh, ok. Tegger in Canada says:
    "The piston does not rotate. Instead, there is a worm-screw attached to the piston, and THAT does the rotating. There is a strong spring, held in by a snap-ring, that keeps the screw seated against the rear face of the caliper bore (actually against a movable plate that's inside there). There are bearings that allow the screw to turn even though there is spring-pressure against it.

    When you step on the brake pedal, these things happen:
    1) hydraulic force acting on the piston pushes the piston forwards, pulling the worm-screw with it;
    2) the spring-pressure opposes the piston's direction; the worm-screw rotates against the spring-pressure, backing out of the piston. This is what provides the adjustment for pad-wear. This is also the reason you need to screw the piston in again, to undo all the backing-out that the screw has been doing."
     
    #10 Pseudonymm, Nov 27, 2019
    Last edited: Nov 27, 2019
  11. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    I have a hard time getting my head around it, but I believe the piston will "attempt" to turn. In particular when you push down the parking brake pedal? The internal spring is interesting: it only allows the rotation in one direction, unscrewing IIRC. Turn the other way and it constricts, locks. It does need to unscrew, gradually, as the pads wear, to maintain the usual clearance.

    The two things that prevent it from unscrewing, are the spoke pattern on the face of the piston, and the stubby pin on the back of of the brake pad. It's paramount for the pin to be between the spokes, and solidly seated there. That's what keeps the piston from turning, screwing out. If the piston spokes do manage to ride up on the pin, that causes terrific/constant drag, bevelled pad wear, scoring rotors, rust zone on inside face of rotor (due to lack of pad contact).

    It's a finicky system, easily screwed up if you're not careful. I've found the best approach to avoiding issues is to assemble it corectly (piston oriented so the pad pin is between spokes), push the brake pedal multiple times to seat everything (but don't use parking brake), test drive, return to garage and apply/release parking brake a few times, then raise the rear once more and verify the wheels are turning relatively freely.
     
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