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How to adjust camber and toe on a Gen III -- front and rear wheels.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by DadofHedgehog, Sep 2, 2016.

  1. DadofHedgehog

    DadofHedgehog Active Member

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    I just wore out my 90-thousand mile Michelin Defenders in about 50 thousand miles and decided to something about it. Note: tires were rotated every 5 k. All four tires were abnormally worn on outside and inside shoulders, close enough that the rubber on the shoulders was showing the edge line of the underlying the thread belts.

    Note #2: about two years ago, I put Cusco coilovers and shocks on my PiP (described elsewhere). Once I had that setup aligned, I didn't touch it until now.

    After the Ken Towery tire chain local shop plopped my new Michelin on, I spoke at length in the pit with their alignment mechanic, who was able to adjust the front toe and then pointed me to aftermarket camber lobe bolts for the front. He also said to try and find Toyota camber bolts if I could rather than aftermarket ones.

    I did, and here is the Toyota URL:

    https://techinfo.toyota.com/t3Portal/document/rm/RM1290U/xhtml/RM000001Y3B015X.html?sisuffix=ff&locale=en&siid=1471310109452

    When you scroll down to the bolt table 3/4 way down the page, you'll notice that Toyota sells "select" bolts for to adjust the front wheel "knuckle" which controls camber. Each knuckle holds two such bolts.

    After a good alignment, it is important to note which way (positive or negative) and how many degrees your camber is off and buy the appropriate two pairs of these select bolts to correct for that yaw. In my case, I needed a pair of three-dot bolts for the right and a pair of one-dot and three-dot bolts for the left side. The table within the URL shows you which pairs you'll need.

    Each of these bolts is identified by one, two or three cast dots on their head, just like in the illustration. Their part # is identical to the stock Toyota bolts, except for the suffix, "A" for the stock bolt, "B" for the one-dot bolt, "C" for the two-dot bolt and "D" for the three-dot bolt.

    The bolts differ by slight differences of thickness on their shaft non-threaded sections.

    All the bolts are about $10 - $17 each.

    At one Toyota dealership, no one knew about these bolts or their adjustment purposes. At another Toyota dealership, a smart parts guy and a mechanic were savvy and explained how they work and checked whether I had selected the correct pairs for my camber correction.

    Once I had the car on a lift (I have free access to a lift bay somewhere else) and I removed the tires, it was actually really easy to swap out the bolt pairs. I also used new nuts, at about $5 each. Job was done in just over 30 minutes. Torque per bolt = 177 foot-pounds.

    The trick to correct front wheel camber once your new bolt pairs are on is to finger-tighten the bolts, then to grab the wheel's top and bottom and to pull the top away from the car to correct for too positive a camber or to push the top toward the car to correct for too negative a camber. If you match the correct corrective bolt pair from the table in the URL above, it is all supposed to "land in the zone".

    ..and that's exactly what happened. I went back to the Ken Towery shop and my front camber was just about perfect on both sides. My toe on both sides was now way outside of tolerances, but the mechanic fixed that fast.

    Pleased with the result and trying to preserve my new Michelins, I got ambitious, read other old PriusChat threads and today, pulled both rear hubs to fix their toe as well, using NAPA full-contact .25 degree shims (my rear camber was good on both sides). I'm due at Ken Towery Shop tomorrow afternoon for a passive laser check on whether I did my calculations right -- if I did, I'll have good toe and camber on all four corners.

    Final note: at 98 thousand miles, both the rear wheel hubs were absolute bastards to break loose. I soaked them with PB Blaster solvent, and it still took an 18-inch pipe wrench, a four-foot cheater pipe and two guys using their body weight to break the right rear hub free. The last time I had exerted such force for mechanical disassembly, I was breaking M-1 Abrams tank track back in the Army in the 90s.

    I'm sharing this as I and others here had often been told that "Prius front camber is not adjustable" and that "Prius rear axle does not allow any camber or toe alignment". I hope this is useful info.

    My thanks go to PriusChat member The Critic and his old thread discussions re: EZ Shims and NAPA shim use on rear wheels, for pointing me in the right direction to adjust the rear wheels.

    Posted via the PriusChat mobile app.
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    My tires are wearing fine, I would never get into anything like this, but good for you, diving into something this tough, and sharing. (y)
     
  3. DadofHedgehog

    DadofHedgehog Active Member

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    Glad you liked it... I love the Michelin Defenders and want to give them a chance at max life, and besides, I'm on vacation so why not wrench around? ;-) might learn something without spending $$$ for someone else to do it, maybe well/maybe not so well.

    Posted via the PriusChat mobile app.
     
  4. RightOnTime

    RightOnTime Senior Member

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    That is some very useful information! Thanks for the Post :)
     
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  5. serge9898

    serge9898 Junior Member

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    Hi Dado,
    Thank you for this excellent and helpful post!!!

    I have the same issue on my 2015 Plugin: Excessive Negative Camber on rear wheels creating excessive tire wear on the inside.

    My mechanic offered to add shims but eventually said it was not possible on the Plugin (because of the disk breaks..?).
    He is not aware about the Toyota "select" bolts for to adjust the front wheel "knuckle" which controls camber.
    I don't have access to the Toyota Techinfo URL...

    1. Can you help me to identify the correct bolts?
    2. Is there a tutorial somewhere on how to do that?
    3. Is it something I could do myself? (I do replace my break pads and disks, but that's about my current skills so far)

    Thank you!
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    To put in shims for rear camber I think the wheel bearings have to come off, not trivial.

    What is the camber currently? The wheels are supposed to splay put at the bottom; the question is how much, and I guess it’s good for the two sides to roughly uniform.

    I’ve got the specs here; could post.

    i think you can measure the camber yourself pretty accurately, if the cars sitting on a smooth concrete slab, and you slide a carpenter square up to it. Measure the gap (typically at top) and do the math (involves trigonometry).
     
  7. CR94

    CR94 Senior Member

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    If the cars's on a level flat surface, you also can do that accurately with a carpenter's level. (Your method would work on a surface that flat, but not level.)
     
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