Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 23

PM-30

Suspension

PERIODIC MAINTENANCE SERVICES

3. WHEEL ARCH HEIGHT

1) Unload the vehicle, so that it is at curb weight.

2) Check the wheel arch height of the front and rear

suspensions to ensure that they are within toler-

ance. <Ref. to FS-8, Wheel Alignment.>

3) If the wheel arch height is out of the specifica-

tion, visually check the following components and

replace deformed parts.

• Suspension components [Front strut assembly

and rear shock absorber assembly]

• Parts connecting suspension and body

4) When no components are deformed, adjust the

wheel arch height by replacing the suspension for

which the wheel arch height is not within tolerance.

<Ref. to FS-8, Wheel Alignment.>

4. WHEEL ALIGNMENT OF FRONT SUS-

PENSION

1) Check the alignment of front suspension to

make sure the following items are within tolerance.

• Toe-in

• Camber

• Caster (referential value)

• Steering angle

<Ref. to FS-8, Wheel Alignment.>

2) When the caster angle does not conform to the

reference value obviously, visually inspect the fol-

lowing components and replace deformed parts.

• Suspension components [Strut assembly, cross-

member, front arm, etc.]

• Parts connecting suspension and body

3) When the toe-in and camber are outside of the

tolerance value, adjust each one so that they con-

form to the tolerance value.

4) When the rotating angles of the right and left

tires are not within tolerance, adjust them to stan-

dard. <Ref. to FS-8, Wheel Alignment.>

5. WHEEL ALIGNMENT OF REAR SUS-

PENSION

1) Inspect the alignment of the rear suspension and

check the following items are within the specified

range.

• Toe-in

• Camber

• Thrust angle

<Ref. to RS-8, Wheel Alignment.>

2) If camber is out of the specification, visually

check the items listed below. If the deformation is

found, replace the damaged part.

• Suspension component [shock absorber, front

lateral link, rear lateral link, upper arm, trailing link,

sub frame etc.]

• Parts connecting suspension and body

3) If the toe-in or thrust angle is out of the tolerance,

adjust to the tolerance value. <Ref. to FS-8, Wheel

Alignment.>

6. OIL LEAKAGE OF STRUT AND SHOCK

ABSORBER

Visually inspect the front strut and rear shock ab-

sorber for oil leakage. Replace the front strut and

rear shock absorber if oil leaks excessively.

7. TIGHTNESS OF BOLTS AND NUTS

Check the bolts and nuts for looseness. Retighten

the bolts and nuts to specified torque. If the self-

locking nuts and bolts are removed, replace them

with new parts.

Front suspension: <Ref. to FS-2, General Descrip-

tion.>

Rear suspension: <Ref. to RS-2, General Descrip-

tion.>

8. DAMAGE TO SUSPENSION PARTS

Check the following parts and the fastening portion

of the vehicle body for deformation or excessive

rusting which impairs the suspension. If necessary,

replace the damaged parts with new parts. If minor

rust formation, pitting, etc. are noted, remove the

rust and take rust prevention measure.

• Front suspension

• Front arm
• Crossmember
• Strut

• Rear suspension

• Sub frame

• Front lateral link
• Rear lateral link
• Upper arm

• Trailing link
• Shock absorber

• In the area where salt is sprayed to melt snow on

a road in winter, check suspension parts for dam-

age caused by rust every 12 months after lapse of

60 months. Take rust prevention measures as re-

quired.

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PM-31

Wheel Bearing

PERIODIC MAINTENANCE SERVICES

21.Wheel Bearing

A: INSPECTION

1. FRONT HUB UNIT

1) Jack-up the front side of vehicle.

2) While holding the front wheel by hand, swing it in

and out to check that there is no bearing free play.

3) Loosen the wheel nuts, and remove the front

wheel.

4) If the bearing free play exists in step 2) above,

attach a dial gauge to hub and measure the loose-

ness in the axial direction.
Service limit:

Straight-ahead position within 0.05 mm

(0.0020 in)

5) Remove the bolts and self-locking nuts, and ex-

tract transverse link from the front crossmember.

6) Remove the AAR of front drive shaft from trans-

mission. <Ref. to DS-14, Front Axle.>

7) While supporting the front drive shaft horizontal-

ly with one hand, turn the hub with the other hand to

check for noise or binding.

If the hub is noisy or binds, replace the front hub

unit.

2. REAR HUB UNIT

1) Jack-up the rear side of vehicle.

2) While holding the rear wheel by hand, swing it in

and out to check bearing free play.

3) Loosen the wheel nuts, and remove the rear

wheel.

4) If the bearing free play exists in step 2) above,

attach a dial gauge to hub and measure the loose-

ness in the axial direction.
Service limit:

Straight-ahead position within 0.05 mm

(0.0020 in)

5) Remove the EDJ of the rear drive shaft from the

rear differential. <Ref. to DS-35, Rear Drive Shaft.>

6) While supporting rear drive shaft horizontally

with one hand, turn the hub with the other to check

for noise or binding.

If the hub is noisy or binds, replace the rear hub

unit.

PM-00408

PM-00408

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PM-32

Axle Boots & Joints

PERIODIC MAINTENANCE SERVICES

22.Axle Boots & Joints

A: INSPECTION

1. FRONT AND REAR AXLE BOOTS

Inspect the front axle boots (A) and rear axle boots

(B) for deformation, damage or failure. If faulty, re-

place with new part. <Ref. to DS-27, Front Drive

Shaft.> <Ref. to DS-35, Rear Drive Shaft.>

2. PROPELLER SHAFT

Inspect the propeller shaft for damage or failure. If

faulty, replace with new part. <Ref. to DS-11, Pro-

peller Shaft.>

PM-00390

(A)

PM-00391

(B)

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PM-33

Tire Rotation

PERIODIC MAINTENANCE SERVICES

23.Tire Rotation

A: INSPECTION

1) When the tread has worn down to less than 1.6

mm (0.063 in) or the wear indicator appears across

the tread, replace the tire. (Replace the right and

left tires as a set.)

2) If the tire appears to be worn unevenly, adjust

the wheel alignment.

3) Next, make a tire rotation between front and rear

as shown in the figure, make sure tires are worn

evenly.

• When the direction of tire rotation is not specified

• When the direction of tire rotation is specified

(A) New tread
(B) Damaged tread

(C) Tread wear indicator

(1) Front

(1) Front

(A)

(B)

(C)

PM-00080

WT-00113

1

WT-00115

1

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