Which push rods are binding? If they are the ones for both the elevator and rudder, it might indicate that you glued the ply piece with the 2 holes for the guide tubes comming into the servo compartment too high on the former. That can cause binding (been there, done that). If you are using standard servos, the piece should only be like 1/8th of an inch up from the surface of the servo tray. To stop the throttle servo from doing this, you can put a medium "Z" bend close to the servo. I did this after also getting a lot of binding/noise from my servos and it made all the difference. Just remove and reglue the rear ply piece after checking the alignment with the pushrod ends next to the servo arms.

Don