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Snapped bolt on HV battery after too much torque

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by GreenTea&SaltWater, Apr 22, 2023.

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  1. GreenTea&SaltWater

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    How can I remove it? Also, I know that some of the nuts/bolts that keep this metal lid closed work as ground and the HV battery won't work if they aren't screwed on. Does the one I broke also work as ground? I started my car and it works fine for now. It does look like it's still making contact.
     

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  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Bolt extractor bit? It's got aggressive, reverse threads. They usually come in a set, an array of diameters for different bolt diameter. They likely spec the bolt diameter at the threads, not the socket size. It's more'n likely either 6 or 8 mm.

    You need to carefully drill a pilot hole (diameter usually spec'd with the set). I've found it helps to drill that diameter, then maybe enlarge it with a slightly larger bit. Also good to centre-punch before drilling the pilot hole. Then using the the appropriate extractor bit, and the drill set to counterclockwise, push firmly, press the button, and pray.

    That said, I doubt one bolt missing will cause any problems; you can leave this till convenient.

    Using an electric impact to install bolts?
     
    #2 Mendel Leisk, Apr 22, 2023
    Last edited: Apr 22, 2023
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  3. GreenTea&SaltWater

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    so i already closed everything up but i checked out some youtube vids to see if the part it screws into is flat, and it is. I may be able to just unscrew it from the bottom with some pliers. Do you know if that bolt works as ground? That's the more important part. I wouldn't want the lid to shake loose enough for the hv battery to stop working while driving around. That's actually the reason I opened it up, because some recent hot weather loosened up the nuts and bolts on that lid and the check hybrid error came on.

    i snapped the bolt by hand using a ratchet wrench
     

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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    I doubt that one bolt would be important, either structurally or electrically. And the car's running. Yeah if you can grab the bolt from below that's much easier.
     
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  5. PriusCamper

    PriusCamper Senior Member

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    This is good practice... It's rare to find a snapped bolt this accessible...

    First step it to use a center punch into the middle of the bolt. Automatic center punches are ideal. Then you need to drill a narrow pilot hole into the bolt, then make it large enough to twist in a bolt extractor.

    Or alternatively open the case and grab the back end of that bolt with vice grips and unscrew it.
     
  6. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    You should be able to grab that by the threads and remove it next time you have the cover off. No big deal.

    Sometimes it helps to start a bolt with fingers only, and whether you use a tool or not it always helps to rotate the fastener backwards until you feel it drop into the thread before changing to clockwise for tightening.
     
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  7. GreenTea&SaltWater

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    The Check HV warning just came up again. It's either something else or the missing snapped bolt is causing it to malfunction. I know those bolts and nuts do matter because like I said, there were two instances I forgot to screw the lid on or didn't screw in all the bolts and nuts and my HV battery was acting up. I'd like for someone with experience to let me know for certain.
     
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  8. GreenTea&SaltWater

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    I took off the lid to inspect and I was wrong about the location of the bolt, it doesn't go into the small metal flap, it just screws into this little metal nipple. What is the purpose of that if it doesn't screw anywhere? Does that look like a ground spot?
     

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    #8 GreenTea&SaltWater, Apr 22, 2023
    Last edited: Apr 22, 2023
  9. Tbkilb01

    Tbkilb01 Active Member

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    I drive with no cover ... keeps battery cool...er?