go buy yourself a digital caliper and get the measurements from the book and rebuild it. This will help..

my original MX400, the servo would hang up on one of the nuts for the other servo. I filed the nut smooth, things quit hanging up and it flew great. The servo that controls the left/right swash was hanging on the nut that sits below it when it's moved up and down. (had a brainfart and can't remember names of things right now)