CGR,

The force that broke the rudder may have affected the servo gears and linkages and clevis.

Check the operation under load, as combatpigg has suggested.

The needle valves are like a bottle neck, where junk likes to become solid when it has been dry for so long.
Soaking them in fuel for several hours may also prevent tuning head aches, and that is a good opportunity to check the o-rings out.

Best luck!