power steering CHEVROLET DYNASTY 1993 Workshop Manual

cle and or engine application the Saginaw T/C style
power steering pump is used on, it will be equipped
with a plastic integral or remote mounted power
steering fluid reservoir. Drive tangs on the power steering gear pinion, mate
loosely with the stub shaft of the steering gear. This
will allow manual steering control to be maintained, if
the drive belt on the power steering pump should
break. However, under these conditions, steering effort
will significantly increase.
STEERING COMPONENTS SERVICE DIAGNOSIS
POWER STEERING PUMP SERVICE
The service procedures for the Saginaw power steer-
ing pump are limited to the areas and components
listed below. No repair procedures are to be done
on internal components of the Saginaw power
steering pumps.
² Repair of power steering fluid leaks from areas of
the power steering pump sealed by O-rings is allowed
(See Pump Leak Diagnosis). However power steering
pump shaft seal leakage will require replacement of
the pump.
² Power steering fluid reservoirs, related components
and attaching hardware.
² Power steering fluid reservoir filler cap/dipstick as-
semblies. Because of unique shaft bearings, flow control levels
or pump displacements, power steering pumps may be
used only on specific vehicle applications. Be sure that
all power steering pumps are only replaced with a
pump that is the correct replacement for that specific
application. Hydraulic pressure is provided for operation of the
power steering gear by the belt driven power steering
pumps (Fig . 1 & 2). It is a constant displacement, vane
type pump. The power steering pump is connected to
the steering gear by a power steering fluid pressure
hose and return hose.
Rectangular pumping vanes in the shaft driven rotor,
move power steering fluid from the intake to the cam ring
pressure cavities of the power steering pump. As the rotor
begins to turn, centrifugal force throws the vanes against
the inside surface of the cam ring to pickup residual oil.
This oil is then forced into the high pressure area. As more
oil is picked up by the vanes. That additional oil is forced
into the cavities of the thrust plate through two crossover
holes in the cam ring and pressure plate. The crossover
holes empty into the high pressure area between the
pressure plate and the housing end cover.
As the high pressure area is filled, oil flows under
the vanes in the rotor slots, forcing the vanes to follow
the inside surface of the cam ring. As the vanes
reach the restricted area of the cam ring, oil is
forced out from between the vanes. When excess oil
flow is generated during high-speed operation, a regu-
lated amount of oil returns to the pump intake side
through a flow control valve. The flow control valve
reduces the power required to drive the pump
and holds down temperature build-up.
Fig. 1 Saginaw Ham Can Power Steering Pump
Fig. 2 Saginaw T/C Style Power Steering Pump
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POWER STEERING SERVICE DIAGNOSIS
Ä STEERING 19 - 3

POWER STEERING SERVICE DIAGNOSIS
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POWER STEERING SERVICE DIAGNOSIS
Ä STEERING 19 - 5

POWER STEERING SERVICE DIAGNOSIS
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POWER STEERING SERVICE DIAGNOSIS
Ä STEERING 19 - 7

POWER STEERING SERVICE DIAGNOSIS
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When steering conditions exceed maximum pres-
sure requirements, such as when the wheels are
turned against the stops. The pressure built up in
the steering gear exerts pressure on the spring end of
the flow control valve. The high pressure lifts the re-
lief valve ball from its seat and allows oil to flow
through a trigger orifice located in the outlet fitting.
This reduces pressure on the spring end of the flow
control valve which then opens and allows the oil to
return to the intake side of the pump. This action
limits maximum pressure output of the pump to a
safe level. Under normal power steering pump operating con-
ditions, pressure requirements of the pump are below
maximum, causing the pressure relief valve to re-
main closed.
CHECKING POWER STEERING FLUID LEVEL
WARNING: FLUID LEVEL SHOULD BE CHECKED
WITH ENGINE OFF TO PREVENT INJURY FROM
MOVING PARTS. DO NOT USE AUTOMATIC TRANS-
MISSION FLUID IN THE POWER STEERING SYS-
TEM. DO NOT OVERFILL THE POWER STEERING
SYSTEM.
Wipe reservoir filler cap free of dirt, before check-
ing power steering fluid level. The dipstick should in- dicate FULL COLD when fluid is at normal ambient
temperature, approximately 21ÉC to 27ÉC (70ÉF to
80ÉF). In all pumps add fluid as necessary to obtain
proper level, using only MopartPower Steering
Fluid, or equivalent. DO NOT USE ANY TYPE
OF AUTOMATIC TRANSMISSION FLUID.
POWER STEERING PUMP PRESSURE TEST
The following procedure can be used to test the op-
eration of the power steering system on the vehicle. (1) Check power steering pump drive belt tension
and adjust as necessary. (2) Disconnect power steering fluid pressure hose,
at steering gear or power steering pump. Use a con-
tainer for dripping fluid. (3) Connect Pressure Gauge, Special Tool C-3309-E
(Fig. 1) to both hoses using adapter fittings. Connect
spare pressure hose to gear or pump. (4) Completely open valve on Special Tool
C-3309-E (Fig. 1). (5) Start engine and let idle.
(6) Check power steering fluid level, and add fluid
as necessary. (7) Gauge should read below 862 kPa (125 psi), if
above, inspect the hoses for restrictions and repair as
necessary. The initial pressure should be in the
range of 345-552 kPa (50-80 psi).
PUMP LEAKAGE DIAGNOSIS
Ä STEERING 19 - 9

CAUTION: The following test procedure involves test-
ing power steering pump maximum pressure output
and flow control valve operation. Do not leave valve
closed for more than 5 seconds as the pump could be
damaged.
(8) Close valve fully three times and record highest
pressure indicated each time. All three readings
must be above specifications and within 345 kPa
(50 psi) of each other. Power steering pump maximum relief pressure
is 8275 to 8975 kPa (1200 to 1300 psi.).
² Power steering pump pressures above specifications
but not within 345 kPa (50 psi) of each other, replace
pump.
² Pressures within 345 kPa (50 psi) of each other but
below specifications, replace pump.
CAUTION: Do not force the pump to operate against
the stops for more than 5 seconds at a time because,
pump damage will result.
(9) Open test valve. Turn steering wheel to the
extreme left and right positions until against the stops,
recording the highest indicated pressure at each posi-
tion. Compare pressure gauge readings to power steer-
ing pump specifications. If highest output pressures
are not the same against either stop, the steering gear
is leaking internally and must be replaced.
POWER STEERING PRESSURE SWITCH
New for 1993 M.Y., is the use of an idle quality power
steering pressure switch on some front wheel drive
passenger car applications. The purpose of this switch is to signal the power
train control module, that the power steering system is
putting additional load on the engine. This type of
condition exists when turning the front tires of the
vehicle, when the vehicle is stationary and the engine
is at idle speed. When this condition is sensed by the
power train control module, through a signal from the power steering pressure switch, engine idle
speed is increased. This increase in engine idle speed
compensates for the additional load, thus maintain-
ing the require engine idle speed and idle quality.
The power steering pressure switch is mounted to
the power steering pressure hose on the applications
that require its usage. Refer to (Fig. 1 and 2) below
for the pressure switch location on the different en-
gine applications.
REMOVE
(1) Locate power steering pressure switch on power
steering pressure hose. Refer to (Fig. 1 and 2) for the
engine application showing the location of the power
steering switch. (2) Remove vehicle wiring harness connector from
the power steering pressure switch. (3) Remove power steering pressure switch, from
power steering pressure hose.
Fig. 1 Power Steering Pressure Switch Location 3.0L
Fig. 2 Power Steering Pressure Switch Location 3.3 & 3.8L
Fig. 1 Pressure Test Gauge
19 - 10 STEERING Ä

INSTALL
(1) Install power steering pressure switch into fit-
ting on power steering pressure hose by hand until
fully seated. Then torque power steering pressure
switch to 12 N Im (106 in. lbs.).
(2) Install vehicle wiring harness connector onto
power steering pressure switch. Be sure latch on wir-
ing harness connector is fully engaged with locking
tab on power steering pressure switch.
CAUTION: Do not use automatic transmission fluid
in power steering system. Only use Mopar T, Power
Steering Fluid, or equivalent.
(3) Fill power steering pump reservoir to correct
fluid level. (4) Connect negative cable back on negative post of
battery. (5) Start engine and turn steering wheel several
times from stop to stop to bleed air from fluid in sys-
tem. Stop engine, check fluid level, and inspect sys-
tem for leaks. See Checking Fluid Level.
POWER STEERING HOSES
Service all power steering hoses with the vehicle
raised on a hoist. Cap all open ends of hoses, power
steering pump fittings and steering gear ports to pre-
vent entry of foreign material into the components.
WARNING: POWER STEERING OIL, ENGINE PARTS
AND EXHAUST SYSTEM MAY BE EXTREMELY HOT
IF ENGINE HAS BEEN RUNNING. DO NOT START
ENGINE WITH ANY LOOSE OR DISCONNECTED
HOSES. DO NOT ALLOW HOSES TO TOUCH HOT
EXHAUST MANIFOLD OR CATALYST.
For part reference and part location on the vehicle
being serviced, refer to Figs. 3 to 6. These show the
hose bracket locations, hose routings and fitting loca-
tions by the engine application of the vehicle. Use
these figure numbers when referring to the removal
or installation procedures for the power steering
hoses listed below.
REMOVAL
(1) Remove vehicle's wiring harness connector (if
applicable to vehicle being serviced) from the power
steering pressure switch (Fig .1&2).
(2) Remove bolts from power steering hose routing
brackets to crossmember attachment points. (3) Disconnect power steering hose at opening clos-
est to power steering gear assembly. Drain power
steering fluid from power steering pump and hose
through open end of hose. (4) Disconnect opposite end of hose and remove
power steering hose assembly from vehicle. (5) Discard O-ring or sealing washer located at end
of tube. (6) Remove power steering pressure switch, from
the removed power steering hose for installation into
the replacement power steering hose.
INSTALLATION
(1) Install the removed power steering pressure
switch into replacement power steering pressure
hose. Torque power steering pressure switch to 12
N Im (106 in. lbs.).
Fig. 3 Power Steering Hose Routing 2.2 & 2.5L
Fig. 4 Power Steering Hose Routing 3.0L
Ä STEERING 19 - 11