Rear Brake Drag after Caliper Replacement

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Rustiallian, Mar 21, 2026 at 7:08 PM.

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  1. Rustiallian

    Rustiallian New Member

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    Hello friends,
    I recently replaced both rear calipers + caliper mounts after the parking brake froze up on one side. It turns out the parking brake cable is also frozen on that side, so it remains disconnected. I also replaced rotors, pads, and the outer hoses. I made sure to align the piston with the pin on the pads. I bled the brakes in invalid mode. The slide pins seem to move freely. The brake pads also seem to move sufficiently freely (not super smooth but smooth enough)

    I now am encountering persistent brake drag on both sides. The heels only turn ~1/2 a revolution when pushed. When I first put the pads in before pressing brake at all the wheel spins freely. Once the brakes have been depressed at all, the brakes drag. This is leading to reduced MPG and very hot rear rotors.

    I'm really not sure what to troubleshoot next. Most threads point to improperly aligned calipers as the cause here.

    Any help is appreciated!
     
    #1 Rustiallian, Mar 21, 2026 at 7:08 PM
  2. PriusCamper

    PriusCamper Senior Member

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    As long as your pins slide well and this isn't an issue with braking when driving, then it's time to study from the parking break pedal back to the rear brakes. Search for some Youtube videos that show you the parking brake mechanism... I suspect the cable or a spring are not working properly. I've not worked on these in Gen3, but there's likely also an adjuster that might be too tight.
     
    #2 PriusCamper, Mar 22, 2026 at 5:53 PM
  3. Rustiallian

    Rustiallian New Member

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    Thank you for your reply! I don’t think it’s parking break related - I don’t even have the parking brake connected on the drivers side, and both sides exhibit brake drag. Do you have other idea of what it could be?
     
    #3 Rustiallian, Mar 22, 2026 at 6:20 PM
  4. ChapmanF

    ChapmanF Senior Member

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    Were the replacement calipers Toyota, or aftermarket?

    The information on piston return in this post may be of interest.
     
    #4 ChapmanF, Mar 22, 2026 at 8:02 PM
  5. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Take a look at the rear brake drag link in my signature, relates to a specific issue, misalignment of caliper piston.

    (on a phone turn it landscape to see signatures)
     
    #5 Mendel Leisk, Mar 22, 2026 at 9:07 PM
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