What's the real value to an alignment with McPherson struts?

Discussion in 'The Garage' started by StageLeft, Sep 24, 2008.

  1. StageLeft

    StageLeft No Lifer

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    I just did the struts and just signed off on $79 for an alignment. From what I can tell, castor and camber would only be changeable based on how the spring sits in the spring plate at the top of the strut, and certainly no alignment shop will change that. My struts go into the knuckle with standard bolts; there is no slotting or way to change camber based on how the top of the two bolts connects the strut to the knuckle.

    That leaves us with toe-in, which is changed via a screw on the control arms. I suppose it could possibly change if the strut mount is not aligned precisely as it was initially. Is that all that can really be addressed by an alignment for such a situation?
     
  2. Zenmervolt

    Zenmervolt Supermoderator<br>The Garage<br>Elite member
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    Generally yes, toe is all that is adjusted with a McPherson Strut suspension, though there are adjustable upper mounts that permit caster and camber adjustment for some cars. I doubt that your Maxima is one of them however.

    ZV
     
  3. Demon-Xanth

    Demon-Xanth Lifer

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    I've seen alignment instructions that include ovaling the holes to adjust camber.
     
  4. StageLeft

    StageLeft No Lifer

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    So a shop could potentially drill out part of the knuckle and put new bolts in?
    So, is it really that likely at all that changing struts would have adjusted the toe-in? I mean, I can tell from the pre and post strut that I didn't align the plates the same as they were (in fact, I aligned them a bit better :)), but could the swivelling at the top affect the toe-in?

     
  5. Demon-Xanth

    Demon-Xanth Lifer

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    They file down the holes on the lower end of the strut so rather than being circular they have some play.
     
  6. helpme

    helpme Diamond Member

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    Some cars have replacement "crash bolts" that allow you to get a bit of slop in the mounts to get some camber adjustment. These however, are generally not ideal, since they may not hold the adjustment forever.

    Some aftermarket setups have camber plates or slotted mounts to allow you to adjust the camber.
     
  7. StageLeft

    StageLeft No Lifer

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    Got back, toe was off to some decent degree. I've never had it pull noticeably, but the guy seemed legit.

    Does this mean then that changing struts does not require an alignment job if the car is of the type that typically has no caster or camber modifications?
     
  8. Demon-Xanth

    Demon-Xanth Lifer

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    In theory, yes. But I consider it a good idea to get an alignment.
     
  9. StageLeft

    StageLeft No Lifer

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    Man, it was $86 with tax!

     
  10. bruceb

    bruceb Diamond Member

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    Struts have 2 bolts that hold it to the steering knuckle. They make eccentric bolts for those holes, which are usually a bit oval, to allow the strut to be moved Inward or Outward just a tiny amount. This can affect Caster / Camber. And on some model cars, changing the position of the Top Mount will change the angles slightly. So yes, an alignment is definitely a worthwhile cost. Car will handle better and premature tire wear will not occur.
     
  11. alkemyst

    alkemyst No Lifer

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    dear god...

    trust me, those struts two knuckle bolts can offer a lot of adjustment range.
     
  12. Bignate603

    Bignate603 Lifer

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    You may never feel a problem, you'll just notice things like strange tire wear.
     
  13. DivideBYZero

    DivideBYZero Lifer

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    Just had full four wheel alignment including camber on my M3. There is quite a bit of adjustment at the top of the front towers in the E46. Car feels great.
     
  14. Throckmorton

    Throckmorton Lifer

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    Changing the struts should change the toe, because they'll be slightly different from the old ones. I wouldn't have expected that, but it turns out even if you do something like replace the lower control arms on a solid axle Jeep, with both sides theoretically the same length, you have to realign.