Today I undertook the installation of a Torklift trailer hitch on my new Model S and encountered a scary situation. The Torklift hitch is a custom designed hitch for the Model S and comes with detailed instructions on how to remove the rear bodywork, bottom panels, and bumper crossbars to install the hitch receiver. It installs without any drilling, using existing bolts and nus that are part of the Tesla bumper system. It is a great piece and will allow us to use a bicycle carrier with nothing touching the car.
Installation is quite complex, and for most people would be a job for a body shop. However, we have a lift in our barn and all the needed tools, so I tackled it myself. All went well until I removed the bumper cover. Immediately inside the bumper cover is a second stamped steel bumper cross member that is attached with eight nuts to studs that protrude from the aluminum body. This steel cross member is actually a cover for an extruded aluminum cross member that is the main structural element inside the rear bumper. The instructions are to remove the eight nuts holdng the steel cross member with a 17mm socket wrench, then remove eight more nuts that hold on the aluminum crossbar, using a 15mm socket wrench. The trailer hitch is then mounted behind (forward on the car) both crossbars using the original nuts to hold all three crosspieces (including the new hitch) in place.
Imagine my shock when I saw the following pictures (I hope these links work this is my first try at embedding links on the forum). When I pulled the plastic bumper cover away, it was immediately obvious that Tesla had at least one serious quality control issue when assembling my car. Three of the four nuts holding the right side of the steel bumper crossmember were barely threaded onto their respective studs. They were not even hand tight, but very obviously just started onto the studs and far away fom being seated. The fourth nut was properly torqued to 40 ft. lbs. (the torque recommended in the hitch instructions).
If I had not seen this myself I might not have believed it. It was obvious, and in my opinion, the bumper cover installer would have had difficulty missing the loose nuts left behind by the cross member installer. I do not know if that function is robotic, but doubt it. It is serendipitous that these loose nuts are three of the very fitments that I was going to be removing anyway to position the hitch assembly.
This is disturbing on several fronts. How many people with ths condition would uncover it? The loose nuts are fully enclosed in the bumper cavity and cannot be seen. I presume that only a small fraction of Model S owners will install hitches. It is a big job, and requires removing dozens of screws, the entire rear body panel system, carpets, hatch seal, interior panels, rear key sensor etc. Very few people will ever see these nuts in their cars, and they cannot be inpected without hours of surgery to get the external panels out of the way. These bolts are part of the rear crash protection system and are critical to safety. I presume that this means that our car did not meet its safety design specifications, and we never would have known if it were not for my home wrenching project.
Lastly, if assembly quality is this haphazard, I wonder what else isn't bolted tight where it cannot be seen? Part of me wants to ask TM to do a thorough build-level inspection, removing all interior and exterior panels to ensure everything is properly tightened and torqued. Perhaps this is an isolated assemby error, but I worry that it means smething more fundamental - that in the rush to meet its production objectives, TM is having quality issues on the assembly line. I love my car, but it isn't going to be quite the same after this experience.
Links to detailed pictures follow.