Recirculating-Ball Steering Gear, Pitman Arm & Linkage

Bolted to the inside of the left front frame rail is the heavy-duty cast-iron recirculating-ball power steering gearbox, driving the forged Pitman arm, the long right-hand center drag link, the left-hand tie rod teeing into the drag link, threaded toe-adjustment sleeves, and high/low-pressure hydraulic lines.

Torsion-Bar Rotary Valve & Recirculating Balls: When you turn the steering wheel against tire resistance, a calibrated steel torsion bar inside the input stub shaft twists by a few degrees—rotating a hydraulic spool valve that directs up to 1,100 psi of fluid to one side of the internal rack piston. Simultaneously, a closed loop of hardened steel ball bearings rolls through the spiral grooves between the worm shaft and rack piston, converting rotation into linear motion with almost zero friction before turning the 3-tooth sector shaft and Pitman arm.

Why Haltenberger Linkage Works with Twin-I-Beam Axles: On a Twin-I-Beam front suspension, each front wheel swings through a long cross-vehicle arc pivoted near the opposite frame rail. By attaching the long drag link to the Pitman arm on the left frame rail and running it all the way to the right knuckle—with the left tie rod teeing off the middle of the drag link—the steering rods swing along the exact same arc length as the axle beams, preventing "bump steer" as the suspension moves.