SERVICE MANUAL
All three readings must be within the listed
specifications and must not vary more than 345
kilopascals (50 PSI). If readings do not meet
this criteria, check for loose belt. If no problem
exists with belt, replace pump flow control valve.
7
Increase engine speed to 1500 RPM and record
flow. Subtract this flow from the flow recorded in
Step 2. Flow should not vary more than 3.8
1/MIN (1 GPM). If flow does vary more than 3.8
1/MIN (1 GPM), remove flow control valve and
clean. Check oil condition. If oil is dirty,
disassemble
pump
and
gear,
clean
and
reassemble.
8.
With engine idling, turn wheel slightly in both
directions
and
observe
pressure
readings.
Release wheel quickly; if pressure does not snap
back, disassemble and clean gear hydraulic
control valve. If oil is dirty, disassemble and
clean gear and pump.
9
With engine idling, turn and hold wheel against
wheel stops in both directions. A noticeable drop
in pressure should occur as the wheel hits the
stops. If no drop, or a rise in pressure occurs,
adjust steering gear relief plungers (if so
equipped) or replace steering gear relief valve (if
so equipped) to correct.
Fig. 2 SE-2780 Power Steering Analyzer
EXTERNAL LEAKAGE DIAGNOSIS
The adjacent diagram has been prepared to show
the potential areas of leakage. If leakage occurs in the
areas shown, perform the operation described.
When diagnosing external leakage, always check for
the possibility of system overheating. An indication of
overheating is when the major-
ity of the pump gaskets become hard and brittle within
48,000 kilometers (30,000 miles) of vehicle operation.
Some gaskets normally harden during routine operation,
therefore it is important to determine if the majority of the
gaskets are hard and brittle. Another indication of
overheating is when the power steering fluid has de-
composed and significantly darkened interior pump
surfaces. Occasionally a "burnt" oil odor will be
noticeable with overheated systems. Overheating is
normally caused by restricted lines causing excessive
back pressure or by severe operating conditions. A
complete gasket overhaul and/or addition of a cooler
may be required.
Fig. 3 Suspected Leakage Areas
1.
Check oil level. An overfilled pump reservoir can
be a cause for leakage. The oil in the steering
system expands as heated during normal usage.
If overfilled the excess is forced through the
reservoir cap vent. Operate the engine and
steering
system
until
nor-mal
operating
temperature is obtained. Remove the reservoir
cap and check level. Adjust the oil level as
required. If leakage persists with the oil level
correct and the cap tight, replace the cap.
CTS-4027 - Page 7
SERVICE MANUAL
