I was pretty intimidated by this little project by reading everyone else's troubles with fixing this leak. But it turned out it was a walk in the park. Here's what I used: T60 torx bit, 3/4 ratchet, hollow metal pipe for leverage and torque, and a 9/16 hex key.
I tackled it from underneath since that seemed like the best option. The pin broke loose with only moderate effort on the pipe/ratchet. Since the ratchet doesn't give you enough room between the unibody once you start undoing the pin, I inserted the hex key into the hole on the torx bit and it came undone with plenty of room to spare.
Hope this helps!