What was found
ON TAKEOFF, ON BRINGING THE POWER UP, THE AIRPLANE REQUIRED INCREASING AMOUNTS OF LEFT RUDDER UNTIL IT WAS FULL RUDDER. THE RUDDER THEN SUDDENLY SNAPPED BACK TO CENTERED. ABORTED TAKEOFF AROUND 40KTS. PERFORMED ENGINE RUNS AND VERIFIED DISCPREPANCY. PERFORMED RUDDER BIAS ACTUATOR ADJUSTMENT TEST WITH NO DEFECTS NOTED. OPENED ENGINE COWLING AND PERFORMED CHECK ON RUDDER BIAS BLEED LINES AND FOUND OUTBOARD B-NUT ON BLEED MANIFOLD LOOSE. TIGHTENED B-NUT AND PERFORMED SATISFACTORY OPS CHECK WITH NO DEFECTS NOTED. WORK DONE IN REF AMM 27-20-10.