Subaru Legacy 2003 Service Manual page 3416

GENERAL DIAGNOSTIC TABLE
POWER ASSISTED SYSTEM (POWER STEERING)
1. NOISE AND VIBRATION
CAUTION:
Don't keep the relief valve operated over 5 sec-
onds at any time or inner parts of the oil pump
may be damaged due to rapid increase of fluid
temperature.
NOTE:
• Grinding noise may be heard immediately after
the engine start in extremely cold condition. In this
case, if the noise goes off during warm-up there is
no abnormal function in the system. This is due to
the fluid characteristic in extremely cold condition.
• Oil pump makes whine or growl noise slightly
due to its mechanism. Even if the noise can be
heard when steering wheel is turned at stand still
there is no abnormal function in the system provid-
ed that the noise eliminates when the vehicle is
running.
• When stopping with service brake and/or parking
brake applied, power steering can be operated
easily due to its light steering effort. If doing so, the
disk rotates slightly and makes creaking noise. The
noise is generated by creaking between the disk
and pads. If the noise goes off when the brake is re-
leased, there is no abnormal function in the system.
• There may be a little vibration around the steer-
ing devices when turning steering wheel at stand-
still, even though the component parts are properly
adjusted and have no defects.
Hydraulic systems are likely to generate this kind of
vibration as well as working noise and fluid noise
because of combined conditions, i.e., road surface
and tire surface, engine speed and turning speed of
steering wheel, fluid temperature and braking con-
dition.
This phenomena does not indicate there is some
abnormal function in the system.
The vibration can be known when steering wheel is
turned repeatedly at various speeds from slow to
rapid step by step with parking brake applied on
concrete road and in "D" range for automatic trans-
mission vehicle.
PS-95