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Spare tire knob won't loosen

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by creuzy, May 5, 2019.

  1. creuzy

    creuzy New Member

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    I recently just happened to check what kind of a spare my new to me 2008 Prius has and noticed the puddle of water I have come to know as standard for this model.

    But my big problem now is that I can not remove the knob to get the spare out. I built a wrench with some wood and a couple bolts and now it is turning but not loosening. I can see that the knob bolt goes into a metal structure attached to the floor but I am wondering whether it threads into that structure or if there is a nut that might have been welded on to it that has corroded loose and is now just spinning.

    Either way, I think my only option is to bust off the past knob. Has anyone had to do this on here who might have tips? Can I drill it off?
     
    #1 creuzy, May 5, 2019
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah there's a weld nut below, and the hold-down bolt has likely rusted in it.

    Step one would be to suck all the water out of there, as thoroughly as possible. Is there a styrofoam shim under the tire? That won't help. Get it dry as possible, use a heat gun and compressed air, then try to get some penetrant, a spray can with a long straw extension, into the joint? Then some taps, vibrate the solvent in, and wait a while. When trying to break it loose (without breaking), might help to press down on the rim, take the bolt out of tension.
     
    #2 Mendel Leisk, May 5, 2019
  3. bisco

    bisco cookie crumbler

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    does the threaded rod go thru the bottom of the car?
     
    #3 bisco, May 5, 2019
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    FWIW, on our 3rd gen, pushing a wire through, it goes about 1/2" then hits something. Appears to be double layer.

    Also, best bet to shoot some loosening solvent, I think you'd want to drill a small hole or two, through the plastic cap on the hold-down bolt, right about here:

    upload_2019-5-5_10-47-49.png

    Then run the solvent spray can straw through, trying to angle it towards the bolt.
     
    #4 Mendel Leisk, May 5, 2019
  5. creuzy

    creuzy New Member

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    The threaded rod does not go through to the outside of the car on the Gen2. I was hoping it did and that there was a way to hold something from below, but no. There is a metal structure welded to the floor inside. I can't get anything into that area through the small gap between the jack holder and hole of the spare rim.
     
    #5 creuzy, May 5, 2019
  6. creuzy

    creuzy New Member

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    Here are some photos. I was able to see that the bolt is not actually turning even though the plastic knob is. I don't think that helps my situation any.

    spare holder.jpg threads.jpg bottom holder.jpg
     
    #6 creuzy, May 5, 2019
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  7. frodoz737

    frodoz737 Top Wrench

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    The nut inside the handle is stripped or the nut is spinning inside the handle. Use a high speed to split the handle (knob) off without cutting the threaded bolt.
     
    #7 frodoz737, May 5, 2019
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  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah if you resign yourself to destroying the plastic cap, then you've got much better access. Once it's out of the way, spare tire lifted out, and you're dealing with the bare bolt: maybe something like an electric impact wrench (after lots of penetrant) could vibrate it loose?
     
    #8 Mendel Leisk, May 5, 2019
    Last edited: May 5, 2019
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    #9 Mendel Leisk, May 5, 2019
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  10. Georgina Rudkus

    Georgina Rudkus Senior Member

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    You'd need to cut off the bolt where it threads into the rusted formed sheet metal "captive nut," drill it out to the minor diameter of the threads of the bolt and rethread it with the appropriate size tap. Given that it is a Toyota, the thread will either be M8x1.25 or M10x1.25.

    That's why I always from new, remove this hold down bolt, coat the threads with rustproofing and reassemble it.
     
    #10 Georgina Rudkus, May 5, 2019
  11. frodoz737

    frodoz737 Top Wrench

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    Since the knob is free wheeling on the bolt, you have to get to the nut inside the knob. Once the panel is off there are more options.
     
    #11 frodoz737, May 5, 2019
  12. bisco

    bisco cookie crumbler

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    put a pair of vice grips on the threaded rod after you have removed the plastic knob. spray the rod at the lower nut with doubleyoudeeforty and let it set overnight
     
    #12 bisco, May 5, 2019
  13. creuzy

    creuzy New Member

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    Thanks for all the advice.

    Not seeing any other way, I drilled a series of holes around the middle of the knob and broke it off the metal bolt. Being able to then get the spare and jack holder out of there, I then used the vise grips to loosen and remove the rusty knob bolt.

    Instead of buying a new knob I thought I could just use a bolt - but then I'd have to carry around a wrench or socket to be able to remove it on the road. I suppose I could use threaded rod and a wing but.

    Anyway, success in getting my spare out with minor damage.

    20190506_103526.jpg 20190506_103454.jpg
     
    #13 creuzy, May 6, 2019
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  14. bisco

    bisco cookie crumbler

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    well done! check a salvage yard/ebay
     
    #14 bisco, May 6, 2019
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    New one is about $8 (post #9). I'll wager you'll put some grease on it lol.
     
    #15 Mendel Leisk, May 6, 2019
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  16. frodoz737

    frodoz737 Top Wrench

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    Anti-sieze. ;)
     
    #16 frodoz737, May 6, 2019
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    And find the water leak...
     
    #17 Mendel Leisk, May 6, 2019
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