I have a 2010 Explorer XLT and completed adding a 3rd row. I came across a 2006 Explorer in a junkyard and took the 3rd row out using JPinUSMC's instructions. Since the Explorer had black cloth seats and the 3rd row was leather, my wife convinced me to upgrade the 2nd row to leather as well. I ended up using seats from a 2006 Mercury Mountaineer. In hindsight, it was a good call on her part because the 3rd row works in conjunction with the 2nd row. You don't need to upgrade, but it is more of a convenience to fully move the 2nd row out of the way for kids to get to the 3rd row. The additional instructions I would add is to ensure the side panels have enough spacing for the addition of the the seat belt module. My left side panel had no issues but the right side panel needed an upgrade from the donor vehicle as dbreen3 described. The original right side panel had room for 6 inches before it cut to the side panel but the addition of the right seat belt needed 9 inches before cutting to the panel. (Adding the right seat belt was the most time consuming as there is not a lot of room to tap in threads. I ended up wearing out the Tap Wrench halfway through the install and needed a replacement. Most Tap Wrenches that come in a set are cheap so expect to replace it.) Once the install was complete, I realized just as Bill Socha did that the left side panel also needed an upgrade from the donor vehicle since the tabs at the bottom of the left plastic that contains a cup holder needed notches in the left side panel. The cup holder still works without an upgrade, but, for a few bucks at the junkyard, I might as well swap out the side panels.
In hindsight, here were the items that I used from donor vehicles (2006 Explorer XLT and 2006 Mercury Mountaineer):
2nd row seats
3rd row seats
Left and right side panels
Left and right rear seat belts
Left and right plastic seat trim containing cup holders
Jack holder
Rear cover
Carpet that extended to the front of the 2nd row seat (trimmed it down for the install but better to have more as I ended up sliding the donor carpet under my original and the 2nd row seats installed with no issues)
All the screws, nuts, bolts, clips, tabs, etc.. that I removed to get to the previous items.
I was able to complete the install within a day (started mid morning and finished at dusk). Tapping threads was the most time consuming as I tapped 13 for the 3rd row seats and 5 for the 2nd row seats (4X M12 1.75, 1X M10 1.5). I read aaronajb1981's comment about insurance being an issue if someone gets injured using the 3rd row seats. However, there are 6 bolts holding the rear of the 3rd row seat down and 3 holding the front. Since each of the rear and the center front needed to be tapped, you will know the condition of the work. I had never tapped threads before this project, but I am confident of the work I did.
The T50 Torx and Tap & Die set were the only special tools needed. Everything else was screwdrivers and a mechanical set of tools. Be prepared to get into tight spaces at junkyards as the vehicles don't have power so you will need to be determined. I generally brought 3 toolboxes each time I went to a junkyard as I could see that others had tried to remove the seats but did not have the right tools to complete the task.
If anyone is interested in black cloth 2nd row seats and the components to create storage (in black) where the 3rd row seats are, let me know. My next project is to replace the passenger manual seat with a power seat.
