Chevrolet 70 1969 Series, Shop Manual

Page: 473 / 913

STEERING SYSTEM 9B-22
nut, and w asher. Tighten bolt to torque listed in
"Specifications" at end of this section.
5. Move dust cap down on yoke tube and bend
fangs down to secure in position.
6. If not previously installed, position Pitman
arm on Pitman shaft.
N O T E : Pitman arm and shaft have matching
blank serrations which must be aligned. On vehicles
equipped with 553-DV-67 and 553-DV-70 type power
steering
gears, align scribe mark on Pitman arm
and shaft then install Pitman arm on shaft and se­
cure with pinch bolt, special hardened washer, and
nut. Tighten nut to torque listed in "Specifications"
at end of this
section.
On all other vehicles, install lock washer and
nut to attach Pitman arm to Pitman shaft. Tighten
nut to torque listed in "Specifications."
TROUBLESHOOTING THE
NOISE
Several different types of noise may be heard
with the control valve steering gear. Trouble shoot
noises as follows:
R A T T L E O R C H U C K L E
1. Cause could be loose adjustment. Make ad­
justment as follows:
(a)
On
553- DV
type steering gears, adjust
thrust bearing preload.
(b) On 568-DV type steering gears, adjust
worm bearings and sector gear lash.
2. Noise could be caused by steering gear
being loose on frame.
(a) Check
steering
gear
installation as des­
cribed earlier in this section under "Steer­
ing Gear Replacem ent."
(b) Torque steering gear mounting bolts to
the torque specified under "Specifications"
later in this section.
3. Coupling pin stops hitting against the upper
flange could
also cause this type
of
noise. Realign­
ment of
the
shaft
with the gear or an endwise ad­
justment of shaft should correct this condition.
N O T E : A slight rattle may occur on turns be­
cause of
the
increased
lash off
the high point. This
is
normal.
HISS
There is some noise in all power steering
gears which cannot be eliminated. One of the most
common is the "hissing" sound most evident at
standstill parking with wheels at end of travel. The
"hissing" noise is usually caused by a faulty valve.
D o
not replace the
valve
unless the "hiss” is
extremely objectionable, since the replacement
valve will also have a slight "hissing" noise. Be
7. On conventional cab models and Series R M /
RG-7500, connect drag link to Pitman arm. Adjust
drag link as explained in "M E C H A N IC A L S T E E R ­
IN G " section. Connect power cylinder end socket
assembly to Pitman arm.
8. On tilt cab models, connect idler link or
connecting rod to Pitman arm and attach with nut.
Tighten nut to 125-150 foot-pounds, advance to
nearest slot and install cotter pin.
9. Connect control valve to pump return tube,
pump to control valve pressure tube, and right-
and left-turn tubes from power cylinder or junc­
tion block to control valve ports. Tighten fittings
to torque recommended in "Specifications.”
10. Bleed the system and bring fluid to proper
level as described under "Bleeding Hydraulic Sys­
tem" previously.
POWER STEERING GEAR
sure, however, that the steering shaft and gear
are properly aligned as the shaft rotates, since
misalignment will transmit the "hissing" noise
into the cab.
V A L V E S Q U A W K
Valve squawk when turning or when recover­
ing from a turn may be caused by a worn dampener
ring on the valve spool or by a loose or worn valve
body. In both cases replace faulty parts.
STEERING GEAR LEAKS
IN T E R N A L L E A K S
High internal leakage will cause a momentary
increase in the steering effort when turning the
wheel fast. If this situation should occur, replace
the control valve.
E X T E R N A L L E A K S
To determine the source of external leaks,
thoroughly clean the steering gear and inspect.
External leakage may be due to loose hose con­
nections or damaged hose, adjuster plug seals or
torsion bar seals. Correct external leaks as
follows:
C A U SE R E M E D Y
1. Loose hose connections . Tighten Connections
2. Damaged h o s e ..........................Replace Hose
3. Damaged adjuster plug seals . . Replace Seals
4. Damaged torsion bar seal . . . . Replace Seal
STEERING GEAR MALFUNCTIONS
Each of the malfunctions listed here has a
number of causes and each cause has a remedy.
These causes and remedies are given in the "Trouble
Shooting Quick Reference Chart" later in this sec­
tion.
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L