Chevrolet 70 1969 Series, Shop Manual

Page: 471 / 913

STEERING SYSTEM 9B-20
TUBES, HOSES, AND FITTINGS
Stationary tubes and flexible hoses are used
to carry hydraulic fluid through the power steering
system. These tubes and hoses connect the steer­
ing gear to the power cylinder and hydraulic pump.
N O T E : On vehicles equipped with the F-160
front axle, a junction block is used between the
control valve and right and left power cylinders.
Tag each tube or hose prior to removal to insure
installation in same relative location.
All tubes, hoses, and fittings should be inspec­
ted for leakage at regular intervals. Fittings must
be tightened to torque listed in "Specifications" at
end of this section. Make sure clips, clamps, and
unions supporting tubes and hoses are in place.
POWER STEERING GEAR AND CONTROL VALVE
CONTROL VALVE
The power steering system control valve is
mounted on top of the steering gear housing and is
activated by a torsion bar that tends to keep the
valve in neutral position. Should the torsion bar
break, the spool and valve body "lock up" into a
complete unit that then operates as a mechanical
unit.
The valve shown in figure 5 is an open-cen­
tered, rotary-type, three-way valve. The spool is
held in the neutral position by means of the torsion
bar. The spool is attached by means of a stud fas­
tened to one end of the torsion bar and the valve
body to the other end. Twisting of the torsion bar
allows the spool to displace in relation to the valve
body, thereby operating the valve.
CONTROL VALVE OPERATION
When the valve is in neutral or straight-ahead
position, the fluid flows from pump through the
1 Valve Body
2 Top Cover
3 Valve Spool
4 Valve Spool Dampener
5
Upper Thrust Bearing
6 Spool Spring
7 Stub Shaft Seal
8 Seal Retaining Ring
9 Stub Shaft
10 Torsion Bar Pin
11 Torsion Bar Sleeve
12 Torsion Bar Seal
13 Seal Back-up Washer
14 Needle Bearing
15 Adjuster Plug Lock Nut
16 Adjuster Plug
17 O-ring Seal
18 Torsion Bar
19 Valve Body Ring
20 Back-up Seal
21 Valve Assembly
22 Torsion Bar Cap
23 Back-up Washer
24 Worm Bearing
25 Worm Oil Seal
TPM-9060
25 24
Figure 5 — Power Steering Control Valve (Type 5 S 3 D V I (Typical)
CHEVROLET SERIES 70 -S0 H EAVY DUTY TRUCK S H O P M A N U A L