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Found out what’s causing undercarriage composite to break apart

Discussion in 'Model 3: Interior & Exterior' started by Redrick00, Nov 19, 2018.

  1. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    I see a lot of worry about this lining breaking apart and I am not sure why.

    I haven’t seen anything here that suggests that the lining is not weather capable, and it does not seem particularly absorbent. It’s not cardboard. It can be soaked and maintain full strength as far as I can tell on my car.

    The issues I see are:
    1) Bolts must be present and tight enough to not loosen. I need to look up a torque spec on a torque chart, but mine were at 2ft-lbs which is not enough. If any come off damage can occur.

    2) in winter, possibility of snow chunks from tires dumping on top of the cover weighing it down enough to rip it off. It is hard to tell without having the vehicle lifted, but to me it looks unlikely that this is a problem.

    3) the rear bumper cover can fill with a lot of water (and freeze) when parked facing uphill. When level, there doesn’t seem to be an issue. The bumper cover also has two bottom bolts that must be present and tight. The middle one has no hole AFAIK.

    The bumper cover issue seems unrelated to the composite axle cover issue to me, though they have the common theme of loose bolts causing problems. The composite sheet doesn’t appear to accumulate water from what I have seen in all the prior videos and the other thread.

    Best thing you can do here, in my opinion, is to immediately check that all bolts and washers are present and tighten them to the torque spec.
     
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  2. outdoors

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    tin can see ^
    Vin 2201

    Have center bolt and it is tight. Also have all the clips in the wheel wells that newer cars are missing. As I said earlier. At SC inspected many cars with both clips and center bolt missing. Strange.....
     
  3. bonaire

    bonaire Active Member

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    Conspiracy theory may say that they built some of the rushed cars in Sept and June without some bolts and such, intending to install them before delivery but it wasn't part of the final-check process or not all service centers are checking.

    Sounds like all bolts, which are missing should be installed and not called-out by new-buyers. Otherwise, the end result is a customer-charged comprehensive-insurance repair that may have to be "fought" to be made right. It's now a new checkbox to look at when people are picking up their cars when-new.
     
  4. Lon12

    Lon12 Member

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    I had clips missing. The one I've circled in this picture adds a lot of rigidly to the lower shelf as it attaches there as well. I noticed it moved up and down a lot before the clip was inserted.
    IMG_0555.jpg
     
  5. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #45 AlanSubie4Life, Nov 21, 2018
    Last edited: Nov 21, 2018
    Interesting. I'll have to double check this (it is difficult when the vehicle is not on a lift), but the center bolt hole for the rear bumper cover does not appear to exist on my vehicle (081xxx) - but perhaps it is just misaligned enough that I couldn't feel it or see it.

    I've noticed the missing fender shield retainers and I'll probably just buy some rather than arguing with the service center about them. Looks like adding them can't hurt, the fender lining does move a little bit without it but it doesn't seem like that big a deal. But if you're hitting the fender liner with huge chunks of snow, and it's accumulating frozen slush, maybe it's best for it to be attached as well as possible. I'm in California, so, shrug.

    Mine is an October build so I don't think the "rush" hypothesis works. It's possible it was just cost reduction, but it seems a bit odd. Not a lot of cost!
     
  6. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    Has anyone measured these fender shield retainer plastic "rivets"/"push pins"/"pop-its"? Hole diameter, stem length, flange diameter? I guess I'll go pop out one of the ones I have at some point and get a caliper on it if not...
     
  7. SMAlset

    SMAlset Well-Known Member

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    #47 SMAlset, Nov 21, 2018
    Last edited: Nov 21, 2018
    Distinction noted (not a car person :)). But anything falling off a vehicle unintended would be a safety issue, at least I would consider it to be.

    Our Model 3 is a Sept build, 088xxx. My husband tried to examine and take photos of the underside before it rains here but said he couldn't get a good photo and see much due to the underside being so close to driveway surface. He did say that our middle of the 3-bolt area does not have a bolt in it.

    As to the wheel well holes, we had some but had that on our due bill and they were taken care of then.
     
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  8. reheat

    reheat Member

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    I bought a set of the plastic fasteners on amazon that come with different sizes and used the ones that fit.
     
  9. Eno Deb

    Eno Deb Active Member

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    Same here. I have no bolt (and no threaded hole) in the middle. I have a threaded hole in the left and right ones, but the right bolt is missing. Nothing feels loose though.

    Left:
    [​IMG]

    Middle:
    [​IMG]

    Right:
    [​IMG]
     
  10. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    It's really amazing that these aren't tightened properly! Probably creating a lot of road hazards with bolts flying out. Definitely get this bolt & washer put back. Once you have 10-20 pounds of water (or ice) in your bumper cover, you're going to want it firmly attached in as many places as possible.
     
  11. Redrick00

    Redrick00 Member

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    My car has mfd 07/18 VIN 49xxx. I have not spoken to service as I just found this out a few days ago. I looked into it because I would always find a long streak of water down my driveway when backing out after washing the car.
     
  12. SMAlset

    SMAlset Well-Known Member

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    I'm thinking if you have a selfie stick and set the cellphone camera to flash you might get some decent underbody photos.
     
  13. Redrick00

    Redrick00 Member

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    BC9A4335-60C0-4A04-8DA2-597A7A8A860C.jpeg
    Those are also missing on mine, rear both sides. I don’t think they’re as important as the bumper cover ones but I do plan on putting them on eventually.
     
  14. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #54 AlanSubie4Life, Nov 21, 2018
    Last edited: Nov 21, 2018
    Just park your car pointed downhill when washing, or when rain is expected. The underbody cover isn’t a concern, as far as I can tell. As long as it is attached. My friend suggested that Tesla will provide a software update to remind you which way to park when rain is in the forecast. What other car company can do that! ;)

    Just did a quick survey of the Model 3s in our garage.

    Rear bumper cover:
    Older RWD vehicles delivered in ~March/April have three bolt holes. One that I looked at had the middle bolt, but was missing both of the outer bolts.
    My P3D, October build, has no hole for the middle bolt, but has both of the outer bolts.

    My car:
    It's missing a bolt on the front undercarriage cover which I noted at delivery.

    The rear undercarriage cover has more bolts than I thought - I think it actually has 6 on the leading edge, and at least 2 on the trailing edge, I think. I found a car in the garage without one of these bolts, makes it very floppy on the corner. Seems very common.
     
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  15. Eno Deb

    Eno Deb Active Member

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    My guess is that the factory "forgot" to put in the missing right bolt in the first place. But the middle bolt appears to be a design change since there is no threaded hole behind it. Perhaps their attempt to provide a drain hole?
     
  16. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    Based on how loose mine were, and the pictures earlier in this thread showing loose bolts, I doubt they were forgotten. They simply walk themselves out. It's possible the use scenario is such that threadlocker will be required. I'm not an expert on fasteners, but in the right situations, even very tight bolts can work themselves free.
     
  17. Eno Deb

    Eno Deb Active Member

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    After taking another look at the picture I posted earlier, I think you are right. If you look closely there is a circular imprint around the right hole right where the washer would have been. The middle hole, on the other hand, looks completely untouched.
     
  18. Redrick00

    Redrick00 Member

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    143667FA-9985-4E11-A6AE-2795E2D31C4A.jpeg
    Today while searching I found a thread where they had problems with undercarriage during rain. I posted photo showing where mine dripped and where the person on linked thread had the problem. When I recorded my videos the front of car was about 3” higher than rear because of driveway slant. If I was to park reverse, then I’m sure water would of flowed all the way forward to where the composite broke down on linked thread.
     
  19. Redrick00

    Redrick00 Member

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    Ripped Undercarriage Composite from the rain?
     
  20. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    I understand and am familiar with that thread. But I suspect this is only a problem after a significant number of bolts fall out (which they likely will), and then the whole thing collapses due to rain, wind, and snow.

    I don’t think the composite broke down. It got ripped off because it wasn’t properly attached. That is just a guess on my part.

    I’d like to see a case where there is damage to this cover but EVERY bolt and washer is still present and tight. Then we could suspect the cover material.
     

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