Chevrolet 70 1969 Series, Shop Manual

Page: 481 / 913

STEERING SYSTEM 9B-30
1. If not previously removed, remove cotter
pin, adjuster screw, and ball seats from one end
of the power cylinder. Use a wide blade screw­
driver to turn adjuster screw out. Repeat these
procedures at opposite end of the cylinder.
2. Loosen clamp bolt on the outside of the
socket.
3. Using a wide blade screwdriver to keep the
piston from turning, unthread socket end from
piston rod.
4. Force piston rod in and out of power cyl­
inder to drain remaining fluid.
5. Using Tru-Arc snap ring pliers, remove the
scraper retainer snap ring from groove in piston
rod guide assembly.
6. Apply air pressure to the retraction port
in the guide assembly while at the same time hold­
ing a finger over the extension port (fig. 10). This
will dislodge wiper ring assembly, scraper retain­
er, scraper retainer O-ring seal, and piston rod
seal from the guide assembly.
C L E A N IN G A N D INSPECTION
Clean and inspect the components using clean­
ing solvent and compressed air. Replace all parts
that are not in first class condition.
A S S E M B L Y (Refer to Fig. 11)
1. Lubricate lip of the piston rod seal with a
thin layer of Lubriplate or equivalent, and insert
it into the guide assembly with the " U " of the cup
toward the bottom of opening in guide.
2. Install scraper retainer O-ring seal.
3. Install the scraper retainer in guide with
" U ” side pointing out.
4. Insert the wiper ring assembly; then using
Tru-Arc snap ring pliers, install the retaining
snap ring. Make sure retaining ring is well seated
in groove of the guide assembly.
5. Thread the socket end assembly on piston
rod until it shoulders against the rod.
6. Tighten the clamp bolt securely.
7. At both ends of the power cylinder, install
ball seats; then thread the adjuster screws into the
sockets loosely.
POWER CYLINDER ADJUSTMENT
A X L E M O U N T E D C Y L IN D E R
Adjustment dimensions for all axle mounted
cylinders are shown in Figure 12. Before fully
tightening clamp to tie rod, push steering knuckle
against stop in full left turn position and set pis­
ton shaft to dimension applicable to axle being
used (fig. 12).
SIDE M O U N T E D C Y L IN D E R
No adjustment is required on side mounted
cylinders since the distance between ball stud con­
nections is not subject to adjustment or change.
TROUBLESHOOTING THE POWER CYLINDER
POWER CYLINDER LEAKAGE
IN T E R N A L L E A K S
Internal leakage in the power cylinder will
show up in a momentary increase in driver effort
when turning the wheel fast. If this occurs, replace
complete cylinder assembly.
E X T E R N A L L E A K S
If the power cylinder is leaking externally,
wipe it clean to determine where it is leaking.
Leakage around the piston rod seals may be cor­
rected by replacing the seals. If the power cylinder
still leaks after replacing the seals, the pressure
relief valve is not operating properly and the com ­
plete power cylinder will have to be replaced. Any
leakage around the welds on the cylinder will nec­
essitate replacing the complete power cylinder
assembly. Tighten the hose connections at the ex­
tension and retraction ports if this is a source of
leakage. If tightening the connection does not stop
leakage, replace complete cylinder assembly.
N O T E : Any damage to the cylinder which will
hamper its operation necessitates replacement of
the complete power cylinder assembly. The cylin­
der is not serviced except for the piston rod seals.
N O T E : For additional trouble shooting infor­
mation, refer to ''Quick Reference Troubleshooting
Chart” at end of this section.
TIE ROD ANTI-ROTATION BUSHING
On some trucks covered in this manual equip­
ped with power steering, anti-rotation bushings
are installed over tie rod end studs between tie
rod ends and steering arms (fig. 13). Each bushing
consists of two cupped washers and a rubber wash­
er. Purpose of anti-rotation bushings is to prevent
weight of the power cylinder, which is clamped to
the tie rod, from rotating the tie rod and causing
tie rod ends to bind against the ball studs. Bushings
should be replaced if they become worn enough to
permit rotation of the tie rod.
BUSHING REPLACEMENT
R E M O V A L
1. At each end of the tie rod, remove cotter
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L