GMC 1982 Light Duty Truck Service Manual page 267

maintained approximately 1/2 to 1 inch from top with
wheels in full left turn position.
2. Fill, if necessary, to proper level with G M Power
Steering Fluid or equivalent.
NOTICE: Never use brake fluid in the power steering
pump, or dam age may occur.
B L E E D IN G H Y D R A U L IC S Y S T E M
1. Fill oil reservoir to proper level and let oil remain
undisturbed for at least two minutes.
2. S ta rt engine and run only for about two seconds.
3. Add oil if necessary.
4. Repeat above procedure until oil level remains constant
after running engine.
5. Raise front end of vehicle so that wheels are off the
ground.
6. Increase engine speed to approximately 1500 rpm.
7. Turn the wheels (off ground) right and left, lightly
contacting the wheel stops.
8. Add oil if necessary.
9. Lower the vehicle and turn wheels right and left on the
ground.
10. Check oil level and refill as required.
11. If oil is extremely foamy, allow vehicle to stand a few
minutes with engine off and repeat above procedure.
a. Check belt tightness and check for a bent or loose
pulley. (Pulley should not wobble with engine
running.)
b. Check to make sure hoses are not touching any other
parts of the truck, particularly sheet metal except
where design calls for a clamp.
•c. Check oil level, filling to proper level if necessary,
following operations 1 through 10. This step and
Step " d " are extremely important as low oil level
a n d /o r air in the oil are the most frequent causes of
objectional pump noise,
d. Check the presence of air in the oil. If air is present,
attem pt to bleed system as described in operations 1
through 10. If it becomes obvious that the pump will
not bleed after a few trials, proceed as outlined under
Hydraulic System Checks.
B E L T T E N S I O N
5 /1 6 "
W ID E
N E W 350 N M ax.
B E L T
80 Lbs. M ax.
U S E D 200 N M in.
B E L T 50 Lbs. M in.
U S E D
C O G G E D
B E L T
Fig. 3B 3-11 — Belt Tension C hart
3 /8 " 15/32"
W ID E
W ID E
620 N M ax.
750 N M ax.
140 Lbs. M ax . 165 Lbs. M ax.
300 N M in. 400 N Min.
70 Lbs. Min. 90 Lbs. M in.
250 N M in.
60 Lbs. M in.
POWER STEERING SYSTEM
H Y D R A U L IC S Y S T E M C H E C K S
The following procedure outlines methods to identify
and isolate power steering hydraulic circuit difficulties. The
test provides means of determining whether power steering
system hydraulic parts are actually faulty. This test will
result in readings indicating faulty hydraulic operation, and
will help to identify the faulty component.
Before perform ing hydraulic circuit test, carefully
check belt tension, fluid level and condition of driving pulley.
P o w e r S te e rin g S y s te m Test
Engine must be at normal operating tem peratu re.
Inflate front tires to correct pressure. All tests are made with
engine idling, check idle adjustment and if necessary adjust
engine idle speed to correct specifications listed in Section
6C and proceed as follows:
1. With engine NOT runnning disconnect pressure hose
from pum p and install Tool J-5176 using a spare
pressure hose between gauge and pump. Gauge must be
between shut-off valve and pump (Fig. 3B3-12), Open
shut-off valve.
2. Remove filler cap from pump reservoir and check fluid
level. Fill pump reservoir to full mark on dip stick. Start
engine and, m om entarily holding steering wheel
against stop, check connections at Tool J-5176 for
leakage.
3. Bleed system as outlined under M ainten an ce and
Adjustments.
4. Insert thermometer (Tool J-5421) in reservoir filler
opening. Move steering wheel from stop to stop several
times until thermometer indicates that hydraulic fluid
in reservoir has reached temperature of 150° to 170°F.
NOTICE: To prevent scrubbing flat spots on tires, do not
turn steering wheel more than five times without rolling
vehicle to change tire-to-floor contact area.
5. Start engine and check fluid level adding any fluid if
required. When engine is at normal operating tem pera­
ture, the initial pressure read on the gage (valve open)
should be in the 80-125 PSI range. Should this pressure
be in excess of 200 PSI - check the hoses for restrictions
and the poppet valve for proper assembly.
POWER STEERING
GAGE J-5 1 7 6 -0 1
PRESSURE HOSE TO
P/S GEAR
Fig. 3B3-12-C hecking Power Steering Pressures
3B3-11
AnAPTFR
j-2 2 3 2 6
PRESSURE HOSE
FROM PU M P