GMC 1976 ZEO 6083 Maintenance Manual page 555

Under normal driving conditions, oil pressure
does not exceed 200 psi except when turning corners
where it does not ordinarily exceed 450 psi. Oil pres
sure, when parking, ranges from 900 to 1,300 psi
depending upon road conditions and weight of the
vehicle. The steering effort during normal driving,
ranges from 1 to 2 lbs. and during parking from 2 to
3-1/2 lbs. again depending upon road conditions .
A check valve located under the high pressure
connector seat hydraulically dampens the shock
transmitted to the steering gear when driving on
washboard roads.
LEFT TURN
When the steering wheel is turned to the left, the
relationship between the spool valve slots and valve
body slots is again changed through twisting of the
torsion bar. Pressure immediately builds up against
the upper end of the rack-piston, forcing it down-
ward to apply turning effort to the pitman shaft. The
oil in the chamber at the lower end of the rack-piston
is forced out through the valve body and spool valve
to the pump reservoir.
Figure 24-Power Steering Gear
STEERING 9- 2 3
TROUBLE DIAGNOSIS
For complete power steering trouble diagnosis
see TROUBLE DIAGNOSIS under POWER
STEERING PUMP earlier in this section .
STEERING GEAR REMOVAL
1 . Disconnect the power steering hoses from the
steering gear and cap the hose fittings .
2. Remove the pitman arm shaft nut. Mark the
relation of the pitman arm to the pitman shaft. Dis-
connect the pitman arm from the pitman shaft using
tool number J-24319 or similar puller .
3 . Loosen steering shaft yoke cinch bolt .
4 . Remove the four bolts attaching the gear to the
frame side rail, permit the steering shaft yoke to slide
free of the steering gear stub shaft and remove the
gear .
INLET OUTLET
LOWER THRUST
SEAL "O" RING
BEARING
4 ° RACES
SPOOL)
WORM
VALVE BODY
VALVE SPOOL
TEFLON SEALS
ADJUSTER PLUG
STUB SHAFT BEARING
UPPER THRUST
BEARING
A-4631