Over-Center Preload

NOTE: Adjust thrust bearing preload before adjusting over-center preload.

Ensure steering gear is centered. Loosen pitman shaft adjuster screw lock nut. Tighten pitman shaft lash adjuster screw. Retighten lock nut. Measure gear over-center torque by rotating torque wrench attached to stub shaft in a 90 degree arc, 45 degrees on each side of center. Record highest degree of arc on each side of center. Record highest reading.
Continue adjustment until over-center reading is within specification. See LASH ADJUSTMENT PRELOAD below. Ensure lock nut is tight when reading is obtained. See Fig 1 .

LASH ADJUSTMENT PRELOAD

Application

Over-Center INCH Lbs.(N.m)

⁽¹⁾ Total INCH Lbs. (N.m)

New Gears

6-10 (0.7-1.1)

18 (2.0)

Used Gears ⁽²⁾

4-5 (.5-.6)

14 (1.6)

⁽¹⁾	Total preload is sum of thrust bearing and over-center preload.

⁽²⁾	In service for more than 400 miles.

Fig 1: Adjusting Over-Center Preload

Courtesy of GENERAL MOTORS CORP.