The Cessna mechanic needs to pay attention to the service
manual when troubleshooting badly rigged rudders. The rudder trim tab
has limited authority, and the pilot shouldn't have to hold large
amounts of pedal even if the tabs is off some. There are three possible
defects in this system:
1. A broken right rudder bar return spring. The left spring will pull
the left pedals forward and the pilot has to constantly hold right
rudder to fight it. These springs break rather often.
2. Someone may have fooled with the cable adjustments at the rudder to
center it. Those adjustments never need changing unless the pedals
aren't lined up when the rudder is centered. The rudder centering is
controlled by the nosewheel centering cam at the nosegear torque links,
and adjustments are made by changing the length of the nosegear
steering spring rods.
3 Everything might be OK but someone has bent the rudder trim tab the
wrong way altogether. To get right trim, the tab has to bend left.

The service manual rigging procedures are a bit complex, and a lot of
mechanics just ignore them and end up misadjusting stuff. We've often
found all the control systems way out of whack, sometimes dangerously
so.

Dan