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Tesla Upper Control Arm CRACKED

Discussion in 'Model S: Driving Dynamics' started by alexml500, Aug 16, 2017.

  1. scottm

    scottm Active Member

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    Even so, the dork's approach was wrong. And obsessing like that is not mentally healthy.
     
  2. alexml500

    alexml500 Member

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    Thanks so much for your input

    Yes This really got me thinking that I might have to taken this up further to the city or the college to have them look into those Hazardous Dots.

    My insurance has decided to cover all the repair as well and replacing all the damage wheel. Anyone in the SoCal Area Please do no go to Buena Park TESLA

    The service Adviser Vince is not only conceited and were completely not courteous at all. I am not sure how Tesla's Hiring process work but this adviser need to be gone. Their service adviser is by far the worst i have ever encounter. I been with MERCEDES for over a 15 Years I have not even once encounter any service adviser that were this bad. NO PHONE CALL EVER RETURNED, NO KNOWLEDGE OF THE CAR, Simply the Worst.

    My Only Regret was bring the car to the closest tesla service center. May be that is the reason why they have a 3 star rating on Yelp
    Obviously they will get another 1 star from ME

    Also not sure if TESLA really care about customer service as i have made several request for the Regional service manager as well as the branch manager. NO RESPONSE from both.
     
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  3. scottm

    scottm Active Member

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    Now that your insurance has covered it, you can breathe a sign of relief. However, insurance payments are on the backs of everyone who buys insurance as rates go up. Since the insurance paid for the damage they would have to be going to court / approaching the city or college for reimbursement. Which I bet, they won't. It's not your issue anymore it theirs.
     
  4. DrivingRockies

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    Easy to push the issue with insurance so you don't get hit with it. The subrogation can be requested.
     
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  5. alexml500

    alexml500 Member

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    This is an Update on the control arm cracked issue

    I finally were able to get the vehicle back about week and a half ago but never had a chance to get a chance to sit down to examine the switch out part

    here are some pictures of the 2 upper control arm

    Not sure how this would justify but with such a crack on the control arm I think the car would sustain tremendous damage

    but no body work require to fix the issue only the suspension part replaced, also 2 damage wheels

    I still believe that it is a part integraty issue. Although the part of the wheel were bend the wheel itself still hold up air and cause no vibration when driving. I have not driven the car at a high speed yet. I am waiting for my replacement image1 (3).JPG image1 (2).JPG image1 (1).JPG wheel to arrive before we will take the car on the road again.
     
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  6. McRat

    McRat Well-Known Member

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    Personally, I'd have used an I-beam forging instead of a cutout billet. It would have been stronger at the same weight. But that is not defect, just a less than optimum decision.

    The fracture shape is interesting. If I were going to do fault analysis, I'd look at grain direction. The grain should have been horizontal. The fracture looks suspiciously like a "with the grain" crack, ie - grain direction is 90° out of phase. This occurs when companies use part clustering CNC software to maximumize the number of components that can be made from a single sheet of stock, if you forget about grain direction, some will have the wrong direction.

    Aluminum is like wood. It has a grain direction. Single sharp cracks with no deformation from bending is normally how 'with the grain' failures look. Against the grain usually shows significant bending before the crack becomes visible to the naked eye.

    This is supercritical on flight hardware.
     
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  7. scottm

    scottm Active Member

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    Which way are you suspecting grain might run on this part, and which way are you suggesting the grain should run?

    Refer to diagram below, and the blue and green lines as being "with the grain" in the direction shown, per line.
    Which is which? cracked.jpg
     
  8. scottm

    scottm Active Member

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    p.s. if a machinist were to make aftermarket forged I-beam arms... I'd consider buying a set and proactively replacing them.. if the price was right.

    p.p.s I've seen a sticker on my rear suspension arms that they were made in Canada. And I've seen made in Canada on the front upper A-arms that I just bought because their ball joints are worn. The front upper arms are stamped steel parts, whereas these rear arms are aluminum.. wondering if the same shop in Canada makes all the arms for Tesla?
     
  9. bhzmark

    bhzmark Supporting Member

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    A friend had a S and bent the exact same part after hitting a deep pothole at speed. It was still drivable. If the friend continued to drive it it might have eventually cracked.

    It was replaced pretty easily. not a big deal.

    Very likely some pothole type hit occurred at some point, stressing the metal, and then it eventually failed.

    There is another thread on this.

    (yawn)

     
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  10. Az_Rael

    Az_Rael Supporting Member

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    Aluminum actually has 3 grain directions. Long Transverse, Short Transverse, and Longitudinal. Depending on the alloy they are using, the properties for each of those grain directions are different.

    We once had a problem with a new aluminum alloy we were using at my work. It turned out to be brittle in the ST direction. So even though our grain direction was correct for our load paths, we ended up having cracks when we started using thicker billets that had more of the ST direction involved.
     
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  11. McRat

    McRat Well-Known Member

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    Longitudinally is how the grain should have went on a billet for maximum strength and fracture resistance.

    The blue line is not the optimum direction. The green line would have been superior but not optimal.

    But lacking a beam structure is a more important problem.
     
  12. jelloslug

    jelloslug Active Member

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    There may be other factors at play here for the design. There could have been some mandate for that part to become a sacrificial part to protect other much more difficult to replace parts in the even of a minor impact. It could also have been designed that way for proper crash worthiness aspects.
     
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  13. bhzmark

    bhzmark Supporting Member

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    What was his offense? That he pointed out, what was almost certainly true, and supported by evidence and reason and experience, that the failure was caused by a pothole or other obstacle type hit? Which, by the way, would have to be the case for your insurance to cover it -- your own auto ins doesn't cover mfr defects.
     
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  14. u00mem9

    u00mem9 Member

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    Everything you have stated here is correct. However, over at the MB dealer, they are smart enough to cover all of this in the interest of future sales. That is an attitude that their customers pay a premium to enjoy. If Tesla wants the service network to treat customers like they are at the Honda dealer, many customers will go elsewhere as soon as there are premium EV options...and that day is fast approaching.
     
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  15. David.85D

    David.85D Member

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    #135 David.85D, Sep 22, 2017
    Last edited: Sep 22, 2017
    I think the part did very well. It held together even though it was deformed. The fracture mode looks like textbook tensile overload with failure on a shear plane.

    And I’m not willing to guess anything about grain direction or grain structure without looking at it with a microscope.

    From this distance, it looks like it had a heck of a whallop, it did its job, and give its life trying :(
     
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  16. laromin

    laromin New Member

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    This part is probably not made from billet because the slot that cracked has too small of an internal radius for efficient machining.

    It is quite likely die-cast, as that should be by far the cheapest and fastest way to produce the part in larger numbers.Most of the other suspension parts are die-cast as well.
    Castings in general will have some issues with porosity and are typically far less ductile compared to rolled or forged material.
     
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  17. David.85D

    David.85D Member

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  18. FlatSix911

    FlatSix911 Porsche 918 Hybrid

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  19. McRat

    McRat Well-Known Member

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    My bad, extrusion it is, but that pretty much guarantees the grain goes in the wrong direction and that it's weaker than a forging.
     
  20. David.85D

    David.85D Member

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    I agree with this, with the caveat that it is not evidence of a defect.

    It could certainly be accounted for in the design. We have no way of knowing what materials properties and max loads were used in the design process.

    And, we don’t know if this part was designed to fail first as an energy absorbing mechanism.
     
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