Being a remanufactured box, they are set to predetermined values and that sector shaft may be a bit too snug. It will feel good, but may cause premature wear and the problem your experiencing on the wheel not returning to center. If you mark it and slowly adjust it 1/4-1/2 turn at a time, you really can't mess it up. No need to disconnect the pitman arm either. Just raise the front wheels off the ground, center the wheel, loosen the sector shaft until there is slight play or "backlash", then tighten until it's gone. Finally add an additional 3/8 turn in and lock the jam nut. Make each adjustment with the engine off and lock the jam nut each time. You'll need to keep the Allen wrench in the shaft while tightening the nut to prevent it from turning. It's all in the photos I attached above. If that doesn't fix it, look into purchasing the Moog K7103 upper control arm offset bushings to increase the caster. Lots of threads on these bushings to read up on. Good luck!