The original 80 Series sector shaft is a bit weak for extreme use.
So when it is time to rebuild your steering box, upgrade to the beefier 105 sector shaft that is 10% larger in diameter and will be significantly stronger than the old unit.
Professional installation is required.
( note: on the last picture with the 80 series spline twisting due to steering stress )
This kit comes with
Shaft, Cross ( sector ) 44111-60060
Arm, Pitman 45411-60360 ( LHD )
Gasket kit, Power Steering 04445-60050
Screw, Sector Shaft Adjusting 45357-60030
Nut, Lock 44142-60020