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Major accident 'cos of abnormal behaviour of Punto

Discussion in 'Technical' started by ani1900s, Apr 29, 2014.

  1. Italia-Linea

    Italia-Linea Staff Member Janitor

    Messages:
    2,123
    Pune
    If i believe that the car never hit anything earlier then i shall give you the only possible cause of this happening.

    CV joint giving up. When this particular part gives up the left wheel and right wheel velocity changes happen abruptly and instead of car turning left or right in proper manner it might go straight or anywhere.

    The name itself of this part is Constant Velocity Joint.
    7 people like this.
  2. asimpleson

    asimpleson Esperto

    Messages:
    3,000
    Heptanesia
    Linea 1.3
    ^^That's the closest and perhaps only explanation to this. However, he has not mentioned of any noise during his earlier driving. Could it be that he missed it completely or that there where no indications of CV joints going weak? Hopefully his answer will clarify.
    1 person likes this.
  3. PKMohan

    PKMohan Amatore

    Messages:
    59
    Bangalore
    I believe CV joints has nothing to do with steering going out of control. The main and only function of CV joints is to transfer the torque to the wheels from the engine.

    Whereas steering is controlled by a number of link rods connected till the steering wheel and loss of steering control can happen by breakage of any of these links.

    Breaking of CV joints can only lead to loss of complete power to the wheels but definitely not going out of control.
  4. mahesh.bandel

    mahesh.bandel Amatore

    Messages:
    240
    Pune
    Grande Punto 1.3
    Exactly CV joint has nothing to do with the direction of travel, it's just transferring power to wheels. I have seen the Ani's car and believe me the front right alloy wheel is bent and literally on the verge of breaking. Now if you say that the car hit the bridge railing/wall, the car should have damage on the front right fender, bumper, tyre etc on the outer side but on visual inspection the inside of the alloy is completely bent whereas the outside of the wheel and body are completely safe.

    This clearly shows the wheel has sustained a major impact and caused the steering rack to break. Now the question is, when did this impact happen?

    Cheers,
    Mahesh
    7 people like this.
  5. Vighnesh81

    Vighnesh81 Novizio

    Messages:
    40
    Pune, MH
    Sorry to hear about your strange accident. first time ever heard on a Fiat.
    Fortunately every one is safe thats more imp.


    Sent from my iPhone using Tapatalk
  6. pushkaraj

    pushkaraj Amatore

    Messages:
    107
    Pune
  7. ani1900s

    ani1900s Novizio

    Messages:
    25
    Mumbai
    Mumbai
    Grande Punto 1.3
    Hi Mahesh, firstly thanks for paying a visit to see my car and sharing your thoughts here, appreciate it bro. On the first hit i.e. on left side, the air bags were opened, so could not visually witness the second hit that happened on right divider; but could feel that it did have a second impact from right where the car eventually stopped. Even the screech marks in the pictures indicates that the car after hitting left barricade headed towards right & that it hit on right and moved for 5-10m before coming to a halt (diversion of screech marks also seen). And as there is no damage to right side body (bumper/ fender, or anywhere on right side body), it makes one think & believe that the impact was taken only on right front tyre (the divider has a protruding edge at bottom as seen in picture as well, so hitting the divider at an angle may cause only the tyre to hit this protruding edge and body 'might' remain unharmed; thanks to very good ground clearance of Punto) and rest was consequential damage due to this hit. If it has hit alloy wheel from inner part only, then that is another mystery in a mystery.
    A question that comes in my mind; let us assume that something damaged the inner side of right front tyre and consequentially steering rod damaged and I lost control over wheels, will the car with a damaged right wheel will head towards left doing left right? And what really can cause the wheel to be damaged so badly while driving that it is now on verge of breaking (right tyre in punctured, so a punctured right tyre will cause the car to move in right direction, whereas I went left doing left right).
    Thanks again Mahesh for visiting :)
  8. Italia-Linea

    Italia-Linea Staff Member Janitor

    Messages:
    2,123
    Pune
    Seems you both are not fully conversant with how the CV joint works.

    CV joints are connected to the main drive shaft and the function of CV joints is to transfer continuous power from one shaft to another at varied steering angles.
    So when you are turning left or right it ensures that the power is still delivered to both wheels.

    If either side of the CV joint fails there will be power only to left or right wheel which in turn will throw the vehicle left or right depending on which direction you are turning.

    Example: If you are turning right and the left CV joint fails, instead of making right turn the car will violently swerve to left.
    4 people like this.
  9. mahesh.bandel

    mahesh.bandel Amatore

    Messages:
    240
    Pune
    Grande Punto 1.3
    Completely agree to the above stated point. The point which I intend to make is what you are saying can happen while the vehicle is accelerating, that's when the CV joints and transmission plays a role but when a person is trying to stop the vehicle it is but obvious that the vehicle is not being accelerated and so the CV joint no longer transmitting any power to the wheels and hence the possibilities of it steering the vehicle to any of the sides is ruled out at least in this case.



    Cheers,
    Mahesh
    1 person likes this.
  10. asimpleson

    asimpleson Esperto

    Messages:
    3,000
    Heptanesia
    Linea 1.3
    ^^CV joints will keep functioning in a car in motion, accelerating or otherwise until car is in stand still and unless disengaged from the transmission. Even when brakes were applied in emergency car was still in motion, when the loss of steering orientation happened simultaneously.

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