Found out what’s causing undercarriage composite to break apart

[xilex]

Is this undercarriage something that you can physically rip apart with your hands?

 

[Redrick00]

I have news on the rear undercarriage cover (not the rear bumper cover). I put the back of the car up on ramps to get this information.

• There are 12 10mm bolt/washer combo attachment points for the cover. There is actually a spot for a 13th in the middle, but my car didn't have that (the threaded hole and the cover hole didn't align too well - and it looked like a bolt had never been inserted).
  
• There are multiple drain holes. They are located at the lowest points. Water is not going to accumulate on top of this cover.
• There are several other attachment points at the edges of the cover near the wheel wells, with rivet like joins to metal bars which run above the cover. There are also attachments on each side to the wheel well composite shield.

Attached are a few pictures. If someone has the middle bolt on this cover, please let us know and provide a picture. I especially wonder if the early builds had this bolt? (I'm not talking about the bumper cover middle bolt which we've already discussed.) I'd like to have this last bolt inserted, because it seems to snug the cover up against the bottom of the car by a fraction of an inch. But it might take some forcing to get it past the cover due to the misalignment.

The summary is: This undercarriage composite is quite robustly attached (assuming all bolts are present), and it seems very unlikely that it will sustain damage unless it is not properly attached, or something hits it and damages it.

I definitely don't think car washing or it getting soaked is going to be an issue at all; it's just too well attached & well drained. The effect of snow and ice is a little less clear, but it also seems unlikely to be an issue unless it is a very bad icing situation, or you're driving in deep snow and throwing up a lot of it. It looked to me like the snow being thrown off the wheels would tend to be diverted from landing on top of the cover.

So, as far as the OP goes - I continue to think the damage most likely occurred because the cover was never properly attached. Or, it sustained damage somehow inadvertently, due to road debris.

Definitely no need to do anything to it, other than to make sure it is attached - it's been solidly engineered to remain attached to the vehicle, as far as I can tell.

Thanks for the work, I’ll have to check and see if I’m missing any of those bolts. I watched one of my videos and see where it’s possibly draining from one of the holes you indicated. On the attached screenshot I marked that possible hole location and the spot where it overspills, which is where I first spotted after car wash.

 

[AlanSubie4Life]

No it can’t be ripped apart easily. It’s the same material as the wheel well stuff as far as I can tell.

 

[Redrick00]

Update after latest car wash. Before drilling holes on bumper cover water would spill from front side of felt composite panel leaving one streak of water down the driveway. I covered drilled holes and only left holes 4 & 5 uncovered. On attached image you can now see two streaks of water that drained from drilled holes before over spilling to composite panel.

 

[AlanSubie4Life]

I confirmed with a couple other people that they have the center bolt on the undercarriage composite, and I can see the bolt head in your pictures as well. Mine was very likely never installed, based on the condition of the threads and no imprint marks from a washer.

Guess I have to add another bolt (was missing one on the front at delivery) to the list for the mobile ranger, if they ever contact me! Maybe I will swing by the service center to see what they can give me on the spot. Just can’t leave the car there; it is apparently a dangerous place.

Personally I wouldn’t drill the cover; I plan to park my car facing downhill (it is easy for me) when I wash it from now on. It seems like drainage isn’t perfect but is adequate, except for the bumper cover, with the car facing uphill. That could be bad in freezing conditions, as mentioned.

 

[ChrisH]

My early August build has all 3 bolts in the plastic cover areas.

I can’t see far enough under my car to see how many of the bolts for the composite cover are there/not there.

 

[AlanSubie4Life]

My early August build has all 3 bolts in the plastic cover areas.

I can’t see far enough under my car to see how many of the bolts for the composite cover are there/not there.

Probably easiest to take a picture with a phone, reaching from in front of the rear driver side tire. That way you can relatively easily capture that middle bolt on the composite cover. The rest of the bolts are mostly visible for that cover, with the exception of a couple on each side tucked behind the wheel, which are easy to miss.

 

[reheat]

Tesla has new trunk weather seal design, it might be better at keeping the water out.

 

[ChrisH]

Tesla has new trunk weather seal design, it might be better at keeping the water out.

Interesting. Did they add an additional seal?

 

[reheat]

Interesting. Did they add an additional seal?

It felt like one piece so not and additional seal but a redesign of the old seal with better coverage.

 

[xilex]

Will they replace our old seals?

 

[Redrick00]

Tesla has new trunk weather seal design, it might be better at keeping the water out.

The new weatherstripping will keep water out of trunk but not out of bumper cover. Water enters bumper from behind tail lights. This is the same seal installed on my vehicle after I found my old one had a wide gap to bumper.

 

[ChrisH]

It felt like one piece so not and additional seal but a redesign of the old seal with better coverage.

The coverage looks way better than mine!

 

[Skione65]

The new weatherstripping will keep water out of trunk but not out of bumper cover. Water enters bumper from behind tail lights. This is the same seal installed on my vehicle after I found my old one had a wide gap to bumper.

@Redrick00,

Is this the same wide gap to bumper in the lower left/right corner of the trunk/seal as in my photos? Have a Ranger coming tomorrow to look at same issue.

Ski

 

[AlanSubie4Life]

The new weatherstripping will keep water out of trunk but not out of bumper cover. Water enters bumper from behind tail lights. This is the same seal installed on my vehicle after I found my old one had a wide gap to bumper.

How does this new seal keep water out of the trunk? While it is certainly more aesthetically pleasing, it seems like that gap with the old sea just lets additional water (in addition to the water coming behind the lights) behind the bumper cover - the trunk should still be sealed - because isn’t the only opening to it this seal around the trunk lid? (Which either seal works to seal.)

 

[MP3Mike]

How does this new seal keep water out of the trunk? While it is certainly more aesthetically pleasing, it seems like that gap with the old sea just lets additional water (in addition to the water coming behind the lights) behind the bumper cover - the trunk should still be sealed - because isn’t the only opening to it this seal around the trunk lid? (Which either seal works to seal.)

I was assuming that they were saying that the seal was redesigned around the top to prevent water running off the back window to go over the seal and into the trunk. But maybe that was wishful thinking on my part. I would love to see side-by-side pictures of the old and new design.

 

[Redrick00]

How does this new seal keep water out of the trunk? While it is certainly more aesthetically pleasing, it seems like that gap with the old sea just lets additional water (in addition to the water coming behind the lights) behind the bumper cover - the trunk should still be sealed - because isn’t the only opening to it this seal around the trunk lid? (Which either seal works to seal.)

Yes, both weatherstripping designs keep water out of trunk, I’ve never had water in mine. If someone gets water in their trunk it must be because they didn’t close trunk all the way which has happened to me a couple of times. My concern with gap on my old weatherstripping seal was with water entering the bumper. SC told me nothing would be damaged by water going in there but that they would fix the seal for me. After I had the new seal installed is when I noticed water still entering bumper cover from behind tail lights. The tail lights have small sealing gasket on mounting screws but as you can see on attached image, it’s a cheap seal which might eventually let water seep into trunk.

 

[Redrick00]

@Redrick00,

Is this the same wide gap to bumper in the lower left/right corner of the trunk/seal as in my photos? Have a Ranger coming tomorrow to look at same issue.

SkiView attachment 357465View attachment 357466

Yes, I had the same gap on lower left corner. I was told they had to remove bumper and readjust the seal but when I look at the before pictures it looks like it’s a different seal.

 

[Eno Deb]

@Redrick00,

Is this the same wide gap to bumper in the lower left/right corner of the trunk/seal as in my photos? Have a Ranger coming tomorrow to look at same issue.

I have the same gap in the lower left corner. As others have said, it seems to lead into the bumper. Please let us know what the ranger says.

 

[brkaus]

One is never going to keep water out of the bumper area. The solution is proper drainage.