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[Speculation] Second-hand report of ball joint broken after parking

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One of the first ModelS owners in China just had one of the cardan joints cracked completely during stall parking. It is unthinkable if this happens when the vehicle is moving at high speed. Tesla service center then replaced all 4 cardan joints and responded that 'the cardan joints were improved in 2015'.

In China a couple of owners (delivered in 2014) experienced similar issue. Some owners claim that if the steering wheel is pushed to extreme, they will hear loud noise coming from wheels and the car would be bumping up and down like a boat in waves.

This has not been the case for ModelS delivered in or after 2015. Then the speculation is that there could be potential design flaw that lead to severe security concerns for ModelS delivered in 2014.

Anyone on this forum encountered similar issue?

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Thank you. Editing.

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Just found that I cannot edit my post. Check if moderator can help to delete it or edit it. I believe the right term should be 'steering ball'.

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Sorry it is the 'steering ball' cracked.
 
I'm going to add yet another term. :)

That looks like a ball joint to me. It looks like the stud broke clean off. Not good.

A cardan joint would be the equivalent of one of the half shaft joints breaking and if that wouldn't result in the wheel coming out like that. It would just result in no power to that wheel.
 
Well your term should be the word...

The right front wheel just fell off. 3 cases reported on local forum. If this is a universal issue for 2014 deliveries should a recall be started...

Tesla has previously shown itself to act responsibly regarding safety and recalls. I would like to think that they will keep an eye out on this situation and act appropriately.
That said, road conditions in China are very variable mainly due to poor construction on some roads not being able to cope with the ever increasing traffic flow, extremely overloaded lorries (trucks) and extreme changes of weather in some parts of the country. This leads to heavier wear on suspension parts, especially for cars with larger wheeled, low profile set ups with sportier suspension.

Having driven both 19" and 21" Model S in China I am very much of the view that when I spec my X I will go for the 20" wheels and probably pass on the air suspension.
 
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I agree it is fair to say that road conditions are not perfect and vary from location to location. That being said, this is basic mandatory requirement of build quality for a vehicle. Consumers would never expect to have to worry about that situation with any other brand, entry brands to exotics, in China.

Right now the service responded to this case very quickly, but the concern among owners and potential owners is whether there is broader/universal issue that needs to be uncovered before some tragedy happens, and if there is, would Tesla stand up to admit it and solve it publicly.
 
For whatever it's worth -

From the color banding on the shaft of the stud, it looks like the stud was way overheated and probably lost most of it's strength due to loss of heat treatment prior to failure. The photo of the broken end appears to show severe metal fatigue, which would be consistent with a failure due to loss of strength.

In essence, it looks like the part was severely abused.
 
Do we know exactly what this part is, where it goes in the system, and what it is supposed to look like?

Looking at the first picture, it really looks like the threaded part ends and is then welded to the broken part - there's a line of discoloration that looks to be the result of heating (from the weld?) a little below the apparent joint, and what might be a bit of slag or extra weld material spanning the joint (or could be dirt left on the part for some reason?)

There's some evidence of fatigue damage on the right side of the failure face, but most of what I see in the last picture looks like a static overload failure, I think.
Walter
 
This failure could be from abuse (the pot hole from hell) or it could be any number of manufacturing or assembly errors: Steel not living up to the design spec, due to using the wrong material or improper heat treating... Or it could be as simple as some clown over tightening the nut. If the pre-load is really excessive, it doesn't take much of a bump to push the metal past the breaking point....

This is obviously a serious problem. Please preserve the broken parts and make sure they are sent for failure analysis. Also ask the shop to take their torque wrench and measure the amount of torque needed to loosen the nut on the same part on the opposite wheel. (just keep raising the torque setting a little at a time until the nut breaks free before the wrench clicks) If it's too late for that, just ask the technician who changed them if he thought they were torqued down correctly or were way too tight.

If you have seen more than one of these types of failures, make sure the Service Manager reports the problem to someone from the factory who can figure out what went wrong.

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Also, I would like to Thank Segarvv for taking the time to report the problem here. We have a saying here in America that "the squeaky wheel gets the grease". We don't want to punish anyone for reporting problems. We just need to recognize and fix them.

I'm curious, as a Tesla stock holder, if you are satisfied with how the local Tesla people are handling this? Are they only concerned with fixing the one car, or do you feel like they recognize there could be a larger problem and are trying to figure out the root cause? Also, are they getting the help they need from the factory/experts in California?

Hopefully the organization is responding properly to this, but if you are not satisfied, please tell us why. (Some of the people here have contacts with the factory and may be able to help get the right people interested in/aware of this problem)

This is not necessarily a design flaw.
 
...

Right now the service responded to this case very quickly, but the concern among owners and potential owners is whether there is broader/universal issue that needs to be uncovered before some tragedy happens, and if there is, would Tesla stand up to admit it and solve it publicly.

So far, I don't remember reading about such a problem nor have I found other occurrences of this issue on this forum (TMC).
Considering the number of other issues that can be found in these threads :), it doesn't look as if this is a recurring issue.
Your concerns about this being a 'universal' issue are probably un-justified for now.
 
Do agree something happened to cause the metal part to fail, likely frequent or long time overheating. I wouldn't suggest any intentional behavior by owners until there is evidence that those owners have reasons to do so.

So the suspicion is that potential design issue lead to the result under certain driving behavior or environment but is not with low probability. This is why I am posting to see if anyone here saw the issue. Especially if any Model S delivered in or before 2014 generate loud noise when trying to do a U turn pushing the steering wheels to extreme.

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yep do hope so. The owner in the incident just edited the original post and removed all content. So I suppose PR was effective.

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Well it is quite hard to maintain a car clean in north China or east coast. South-west regions are much better like Hongkong and Chengdu.

The logic shocked me though. First of all White is the fast emerging, if not top selling, color for the recent years, in China. Then white, after silver, is much easier to maintain looking clean than black or other deep colors.

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Thank you for the constructional response. Agree we should not call it a design flaw until fully investigated.

From the original post, there are a few owners, verified or not by the forum, mentioning that Model S (manufactured in 2014, rear engine) moves with loud noise and car body got noticeable vertical movements when turning. It felt like a shaking boat. Service center said to one of the owner that it is a known issue with steering bump, but right now it doesn't look so. I personally saw 2 different individuals posting similar incidents with obviously different car, within the last 2 month, and I was kind of defending Tesla since I believed the first author was trying to blame Tesla for fault of his own.

I believe Tesla local reaction is very quick. They replaced all 4 parts (currently only 1 failed of course). Now the original post content was gone, edited by the owner, stating being contacted by Tesla and signed a NDA. Sad.

Not sure if the local team would report this to headquarter.