Operation; Standard Procedure - Power Steering Pump Initial Operation - Chrysler 2004 Concorde Service Manual

LH
PUMP (Continued)
Fig. 2 Power Steering Pump (3.5L Engine)
1 - POWER STEERING PUMP
2 - PUMP PRESSURE FITTING
3 - FLUID SUPPLY FITTING

OPERATION

The Power steering pump operates as follows. A
belt driven pulley turns a shaft which drives a rotor.
Rectangular pumping vanes carried by the shaft
driven rotor move the fluid from the intake to the
cam ring pressure cavities. 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, the 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 pres-
sure area between the pressure plate and the hous-
ing end cover.
When the high pressure area of the power steering
pump is filled with power steering fluid, the fluid
flows under the vanes in the rotor slots, forcing the
vanes to follow the inside oval 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 regulated 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.
When steering conditions exceed maximum pres-
sure requirements, such as turning the wheels
against the stops, the pressure built up in the steer-
ing gear also exerts pressure on the spring end of the
flow control valve. The end of the valve houses the
pressure relief valve. High pressure lifts the relief
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 con-
trol 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, the pressure requirements of the pump are
below maximum, causing the pressure relief valve to
remain closed.
In the event of a power steering pump drive belt
failure, manual steering control of the vehicle can
still to be maintained. However, under these condi-
tions, steering effort will significantly increase.
STANDARD PROCEDURE - POWER STEERING
PUMP INITIAL OPERATION
WARNING: THE FLUID
CHECKED WITH ENGINE OFF TO PREVENT INJURY
FROM MOVING COMPONENTS.
CAUTION: Use only Mopar ATF+4 Automatic Trans-
mission Fluid (MS-9602). Do not overfill.
Wipe the power steering fluid reservoir and filler
cap clean. Check the level of the power steering fluid
in the reservoir. The power steering fluid level should
be between MAX. COLD and MIN. COLD when the
fluid is at a normal ambient temperature of approxi-
mately 32°C to 43°C (90°F to 110°F).
(1) Fill the pump fluid reservoir to the proper level
and let the fluid settle for at least two (2) minutes.
(2) Start the engine and let run for a few seconds.
Then turn the engine off.
(3) Add fluid if necessary. Repeat the above proce-
dure until the fluid level remains constant after run-
ning the engine.
(4) Raise the front wheels off the ground.
(5) Start the engine. Slowly turn the steering
wheel right and left, lightly contacting the wheel
stops for less than 2 seconds at a time.
(6) Add power steering fluid if necessary.
(7) Lower the vehicle and turn the steering wheel
slowly from lock to lock.
(8) Stop the engine. Check the fluid level and refill
as required.
(9) If the fluid is extremely foamy, allow the vehi-
cle to stand a few minutes and repeat the above pro-
cedure.
(10) Lower the vehicle.
PUMP 19 - 59
LEVEL SHOULD BE