E21 Trunk Floor Repair

As we were finishing up the M42 drive train swap about a month ago, we discovered a decent amount of rust in the trunk of the car. The area of the trunk that sits directly above the exhaust was showing some signs of rust.  There was no clear rust through, but the seam sealer was pushing up from the floor very slightly and there was residue of rust around the panel seams.  Once we started a little digging and probing, this is what we found:

This rust was most likely caused by the repeated heat cycling of the exhaust.  The rust was mostly contained to the area spot welds and welded flanges.  

Joel removed the rusty metal and cleaned the surrounding areas.  A piece of replacement sheet metal was hand formed to replicate the shape of the trunk pan and welded in.

The trunk separation bracket was welded back in.  All of the seams were covered in seam sealer and brushed to replicate the factory appearance.  The area was then epoxy primed.  Please note, while there are no pictures from underneath the car, these processes were repeated on the seams and welds under the car.

We had some factory color mixed from the previous work to the engine compartment and were able to use it to repaint the repair area.  

Luckily, the rust in this car is very minimal and it has failed to expand into the rear shock towers.  This repair came out pretty well and will prolong the life of this E21.