Recently I broke, or should I say mangled, my Tunnel Stay Assembly (rear cross member). I decided to make a sort of DIY on my process of repairing this. I doubt many people will need to replace this as it's not too common and pretty straight forward, but in case people need it, here it is:

Begin simply by just removing the 16 (I think) bolts that hold the TSA on. 3 on each back end, two at the top of each side.

My TSA once I took it off. looks like a pile of scrap metal i know. I guess this is what happens when the previous owner winter drives it for 6 5 years with no under-coating:


The new TSA from Infiniti- $203 with a dealer discount


So first I took it off with somewhat ease seeing how rusted it was. Only two bolts broke on the right side bracket. Unfortunately when my TSA broke (manhole slammed against the bottom) It bent the floor a little where the top left of the TSA bolts on and broke off one of the bolt holes:


This is what it should look like; with a little fabrication, welding and magic, we made it look almost identical:


I had to drill out two screws on the back right side, tap them, and used a Helio-coil (if thats even what its called):


Bought some cheap Undercoating just to re-do the brackets, TSA and the frame where the TSA sits:


Id recommend some thread-locker when you put back each bolt. In my case I had to clean off and shine up each bolt with a wire-wheel.
I'll post a picture of the finished product tomorrow once I put it back on.

And yes i realize my under-carridge looks poor, but trust me, its better in real life. any spots with even the smallest amount of rust was cleaned and undercoated.