I have completely dis-assembled and re-assembled one before.
Go slow, keep the bench clean, keep track of the parts as they come out.
It is built in layers. Easy to understand.
What I cannot tell you is how to adjust the resistor in the top layer
after the cover is off, the last layer you will put back on when putting it
together.
Did you read this particular guide from Chrysler ?
http://www.imperialclub.com/Repair/Lit/Master/281/cover.htm
It does not have the rebuild or even pictures of a disassembled servo.
But an excellent read, with a great schematic of the arm that controls
the fan and compressor electric switches.