GMC 1982 Light Duty Truck Service Manual page 264

3B3-8 POWER STEERING SYSTEM
POW ER STEERING SYSTEM EXTERNAL LEAKAGE
G eneral Procedure
1. Wipe suspected area dry.
2. Check for overfilled reservoir.
3. Check for oil aeration and overflow.
4. Check hose connections - tighten if necessary.
5. Verify exact point of leakage.
Example:Torsion bar, stub shaft and adjuster seals are
close together; exact leakage point could be confused.
Example: The point oil drips from is not necessarily the
leakage point - oil overflowing from reservoir for instance.
6. When service is required:
a. Clean leakage area upon disassembly.
b. Replace leaking seal.
c. Check component sealing surfaces for damage.
d. Reset bolt torque to specifications where required.
C u sto m e r D escriptions
Some of the customer complaints associated with the
power steering system may be reported as:
1. Oil leakage on garage floor.
2. Oil leaks visible on steering gear, pump, or anywhere
else on the left side of engine compartment.
3. Growling noise especially when parking or when engine
is cold.
4. Loss of power when parking.
5. Heavy steering effort.
For the purpose of trouble shooting complaints of this
nature, assume that there is an external leak in the power
steering system.
L e a k a g e D ia g n o s is (F ig . 3 B 3 -8 )
This section is a guide, which will enable you to locate,
identify, and repair leaks in the power steering system. It
contains:
A. Diagram of the complete power steering system with
the areas of potential leakage identified.
B. Recommended procedure for locating external leakage
in the vehicle.
C. Areas of leakage to be checked, which can be serviced
at once.
D. Part replacement recommendations.
E. Diagram of the actual areas where leakage will be
observed and the action recommended to repair this
leakage.
Leakage Check
The purpose of the diagnostic procedure is to pin-point
the location of the leak. The method outlined in this manual
can be followed to locate the leak and repair it.
In some cases you will be able to locate the leak easily.
However, seepage type leaks may be more difficult to isolate.
For seepage leaks, the following method is recommended.
A. With the vehicle's engine off, wipe the complete power
steering system dry
connections).
B. Check oil level in p u m p 's reservoir and adjust as
directed in maintenance section.
C. Start engine and turn steering wheel from stop to stop
several times. Do not hold in corner for any length of
time as this can damage the power steering pump. It is
easier if someone else operates the steering wheel while
you search for the seepage.
D. Find the exact area of leakage.
E. Refer to the diagnostic chart to find the recommended
method of repair.
Quick Fixes
The purpose of this section is to acquaint you with the
types of leakage which can be repaired very easily. It
contains information on reservoir oil level, the hoses and the
hose connections.
An overfilled pump reservoir can be a cause for leakage
complaint. The oil in the steering system expands as heated
during normal usage. If overfilled the excess is forced
thhrough the breather cap hole and may be sprayed over the
engine by air blast. Operate the engine and steering system
until normal operating temperature is obtained. Remove the
reservoir cap and check the graduated level on the dipstick.
Adjust the oil level as required.
Seepage at the hose connections can be a cause for
leakage complaint and can be due to loose connection nuts.
If leakage is observed at the hose connections, and the nut is
not cross threaded, tighten the nuts at the gear to 30 foot
pounds.
The nut at the power steering pump should be tight­
ened to 40 foot pounds. If tightening to this torque does not
stop the leak, refer to the diagnostic chart.
If either the return hose or the pressure hose leaks,
replace the hose.
Component Replacement
Lip seals, which seal rotating shafts, require special
treatment. This type of seal is used on the steering gear at
the pitman shaft, at the stud shaft, and on the drive shaft of
the pump. When leakage occurs in one of these areas,
always replace the seal(s), after inspecting and thoroughly
cleaning the sealing surfaces. Replace the shaft only if very
severe pitting is found. If the corrosion in the lip seal contact
zone is slight, clean the surface of the shaft with crocus
cloth. Replace the shaft only if the leakage cannot be
stopped by smoothing with crocus cloth first.
Housing or Cover Seepage - Both the power steering
gear and pum p assemblies are leakage checked before
shipment. However, occasionally oil seepage may occur
from the gear or pump other than the seal areas. If this type
of leakage is found, replace the leaking part.
Fig. 3B3-8 has been prepared to show the potential
areas of leakage. If leakage occurs in the zones shown,
replace the part listed using the service manual as a guide.
(gear, pump, hoses, and