How to remove the shoulder pylon of a 1st gen. Eva and not kill him trying:

Lift the arm you want to remove the shoulder pylon from...

...and remove it....

Remove the joint from the arm (Revopliers come in handy)

Bend the pylon towards the place the joint is stuffed in...

...and pull it out of it's axis.

Here in detail the pylon and the axis that holds it, you can see the "rail" used to pull the pylon out.

To place it back, just put it on the arm and push it into the axis from "Eva 1" mark side.
Never attempt to place it back pushing from the joint side!!!


There... Wait...
I forgot to tell you about hemorrhages!