Subaru Legacy (2005 year). Manual - part 855

PS-91

POWER ASSISTED SYSTEM (POWER STEERING)

Power Steering Fluid

11.Power Steering Fluid

A: SPECIFICATION

B: INSPECTION

1) Check the power steering fluid for deterioration
or contamination. If the fluid is highly deteriorated
or contaminated, drain it and refill with new fluid.
2) Check the joints and units for oil leakage. If any
oil leaks are found, repair or replace the applicable
part.
3) Inspect the fluid level on flat and level surface
with engine “OFF” by indicator of reservoir tank.
If the level is at “MIN.” point or below, add fluid to
keep the level in the specified range of the indica-
tor. If at “MAX.” point or above, drain fluid by using
a syringe or the like.

(1) Check at power steering fluid temperature
20

°C (68°F); read the fluid level on the “COLD”

side.
(2) Check at power steering fluid temperature
80

°C (176°F); read the fluid level on the “HOT”

side.

C: REPLACEMENT

1) Lift-up the vehicle.
2) Remove the crossmember support.
3) Remove the pipe joint in the center of gearbox,
and connect the vinyl hose to the pipe and joint.
Wipe fluid off while turning the steering wheel.
4) Add the specified fluid to reservoir tank at MAX
level.
5) Continue to turn the steering wheel slowly from
lock to lock until the bubbles stop appearing on oil
surface while keeping the fluid at the level in the
Step 4).
6) If turning the steering wheel in low fluid level
condition, air will be sucked in pipe. In this case,
leave it about half an hour and then do the step 5)
again.
7) Start the engine and let it idle.
8) Continue to turn the steering wheel slowly from
lock to lock again until the bubbles stop appearing
on oil surface while keeping the fluid at the level in
Step 4).
Normally bubbles stop appearing after three times
turning of steering wheel from lock to lock.
9) In case bubbles do not stop appearing in the
tank, leave it about half an hour and then do the
step 4) all over again.
10) Lower the vehicle, and then idle the engine.
11) Continue to turn the steering wheel from lock to
lock until the bubbles stop appearing and change of
the fluid level is within 3 mm (0.12 in).
12) In case the following happens, leave it about
half an hour and then do step 8) to 11) again.

(1) The fluid level changes over 3 mm (0.12 in).
(2) Bubbles remain on the upper surface of the
fluid.
(3) Grinding noise is generated from oil pump.

13) Check the fluid leakage after turning steering
wheel from lock to lock with engine running.

Recommended power steering fluid

Manufacturer

ATF DEXRON III or equivalent

B.P.

CALTEX

CASTROL

MOBIL

SHELL

TEXACO

PS-00463

HOT  MAX

COLD  MAX

HOT  MIN

COLD  MIN

PS-92

POWER ASSISTED SYSTEM (POWER STEERING)

General Diagnostic Table

12.General Diagnostic Table

A: INSPECTION

*1 If the tires or wheels are wider than standard, the load to power steering system is increased. Accordingly, in a condition, for
example before fluid warms-up, relief valve may work before maximum turning angle. In this case, steering effort may be heavy.
When the measured hydraulic pressure is normal, there is no abnormal thing.
*2 In cold weather, steering effort may be heavy due to increased flow resistance of cold fluid. After warming-up engine, turn the
steering wheel from stop to stop several times to warm-up fluid. Then if steering effort reduces normally, there is no abnormal
thing.

Trouble

Possible cause

Corrective action

• Heavy steering effort in all 
ranges
• Heavy steering effort at 
stand still
• Steering wheel surges when 
turning.

1. Pulley belt
• Unequal length of pulley belts
• Adhesion of oil and grease
• Loose or damage of pulley belt
• Poor uniformity of pulley belt cross section
• Pulley belt touches to pulley bottom
• Poor revolution of pulleys except oil pump pulley
• Poor revolution of oil pump pulley

Adjust or replace.

2. Tire and wheel
• Improper tires out of specification*1
• Improper wheel out of specification*1
• Tires not properly inflated

Replace or reinflate.

3. Fluid
• Low fluid level
• Aeration
• Dust  mix
• Deterioration of fluid
• Poor warming-up of fluid *2

Refill, bleed air, replace or 
instruct customer.

4. Idle speed
• Lower idle speed
• Excessive drop of idle speed at start or at turning steering 
wheel *3

Adjust or instruct customer.

5. Measure hydraulic pressure. <Ref. to PS-86, INSPECTION, 
Oil Pump.>

Replace the problem parts.

6. Measure steering effort. <Ref. to PS-95, MEASUREMENT 
OF STEERING EFFORT, INSPECTION, General Diagnostic 
Table.>

Adjust or replace.

• Vehicle leads to one side or 
the other
• Poor return of steering wheel 
to center
• Steering wheel surges when 
turning.

1. Fluid line
• Folded hose
• Flattened pipe

Correct or replace.

2. Tire and wheel
• Flat tire
• Mix use of different tires
• Mix use of different wheels
• Abnormal wear of tire
• Unbalance of remained grooves
• Unbalance of tire pressure

Adjust, fix or replace.

3. Front alignment
• Improper or unbalance caster
• Improper or unbalance toe-in
• Loose connection of suspension

Adjust or retighten.

4. Others
• Damaged joint assembly
• Unbalanced height
• Unbalanced weight

Replace, adjust or instruct cus-
tomer.

5. Measure steering effort. <Ref. to PS-95, MEASUREMENT 
OF STEERING EFFORT, INSPECTION, General Diagnostic 
Table.>

Adjust or replace.

PS-93

POWER ASSISTED SYSTEM (POWER STEERING)

General Diagnostic Table

*3 In cold weather or with insufficient warm-up of engine, steering effort may be heavy due to excessive drop of idling when turn-
ing steering wheel. In this case, it is recommended to start the vehicle with increasing engine speed than usual. Then if steering
effort reduces normally, there is no abnormal thing.

1. NOISE AND VIBRATION

CAUTION:
Do not keep the relief valve operated over five seconds 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 char-
acteristic 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 provided that the noise
eliminates when the vehicle is running.
• When turning the steering wheel with service brake and/or parking brake applied, the noise is generated
by creaking between disc and pads. However this does not indicate abnormal function in system.
• There may be a little vibration around the steering devices when turning steering wheel at standstill, 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 be-
cause of combined conditions, i.e., road surface and tire surface, engine speed and turning speed of steering
wheel, fluid temperature and braking condition.
These phenomena do not indicate there are some abnormal functions in the system.
Confirm the vibration by turning the steering wheel repeatedly at various speeds from slow to rapid step by
step with parking brake applied on concrete road and in “D” range for AT model.

Trouble

Possible cause

Corrective action

Hiss noise (continuous) 
While engine is running.

Relief valve emits operating sound when steering wheel is 
completely turned in either direction. (Do not keep this 
condition over five seconds.)

Normal

Relief valve emits operating sound when steering wheel is 
not turned. This means that the relief valve is defective.

Replace the oil pump.

Rattling noise (intermittent)
While engine is running.

Interference with adjacent parts

Check the clearance.
Correct if necessary.
<Ref. to PS-71, INSPECTION, 
Pipe Assembly [LHD Model].>

Loosened installation of oil pump, oil tank, pump bracket, 
gearbox or crossmember

Retighten.

Loosened installation of oil pump pulley or other pulley(s)

Retighten.

Loosened linkage or play of steering or suspension Loos-
ened tightening of joint or steering column

Retighten or replace.

Sound generates from the inside of gearbox or oil pump.

Replace the faulty parts of the 
gearbox or oil pump.

Knocking
When turning steering wheel in 
both directions with small angle 
repeatedly at engine ON or OFF.

Excessive backlash
Loosened lock nut for adjusting backlash

Adjust and retighten.

Loosened tightening or play of tie-rod, tie-rod end

Retighten or replace.

Grinding noise (continuous)
While engine is running.

Vane pump aeration

Inspect and retighten the fluid 
line connection.
Refill the fluid and vent air.

Vane pump seizing

Replace the oil pump.

Pulley bearing seizing of oil pump

Replace the oil pump.

Folded hose, flattened pipe

Replace.

PS-94

POWER ASSISTED SYSTEM (POWER STEERING)

General Diagnostic Table

Squeal, squeak (intermittent or 
continuous)
While engine is running.

Maladjustment of pulley belt
Damaged or charged pulley belt
Unequal length of pulley belts

Adjust or replace.
(Replace two belts as a set.)

Runout or defacement of V-groove surface of oil pump pul-
ley

Clean or replace.

Sizzling noise (continuous)
While engine is running.

Fluid aeration

Fix the wrong part causing aera-
tion.
Replace the fluid and vent air.

Damaged pipe of gearbox

Replace the pipe.

Abnormal inside of hose or pipe
Flattened hose or pipe

Rectify or replace.

Abnormal inside of oil tank

Replace.

Removed oil tank cap

Install cap.

Whistle (continuous)
While engine is running.

Abnormal pipe of gearbox or abnormal inside of hose

Replace the faulty parts of the 
gearbox or hose.

Whine or growl (intermittent or 
continuous)
While engine is running with/
without steering turned.

Loosened installation of oil pump, oil pump bracket

Retighten.

Abnormal inside of oil pump, hose

Replace the oil pump or hose, if 
the noise can be heard when 
running as well as stand still.

Torque converter growl, air conditioner compression growl

Remove the power steering pul-
ley belt and confirm.

Grinding noise (continuous)
While engine is running with the 
steering turned.

Abnormal inside of gearbox

Replace the faulty parts of gear-
box.

Abnormal bearing for steering shaft

Apply grease or replace.

Generates when turning steering wheel with brake (ser-
vice or parking) applied.

If the noise goes off when brake 
is released, it is normal.

Vibration
While engine is running with/
without steering turned.

Too low engine speed

Adjust and instruct customers.

Vane pump aeration

Fix the wrong part.
Vent air.

Damaged valve in oil pump, gearbox

Replace the oil pump, faulty parts 
of gearbox.

Looseness of play of steering, suspension parts

Retighten.

Trouble

Possible cause

Corrective action