Alittle more to it than that.
1. flip truck over loosen the 4 screws and middle screw holding the linkage onto the servo.
2. flip truck back over and remove the cover over the receiver then disconnect the the steering servo. (if the wires are secured with a ziptie youll need to snip that)
3. then the wire should be free and then gently pull the servo out being careful to make sure you dont rip the wire while pulling the servo out
Good luck !