2006 SUBARU IMPREZA WRX Owners Manual

11-26 Maintenance and service
Clutch fluid (MT vehicles)
Checking the fluid level
Check the fluid level on the outside of the
reservoir. If the level is below “MIN ” level
mark, add the recommended clutch fluid
to “MAX ” level mark.
Use only clutch fluid from a sealed con-
tainer.
Recommended clutch fluid
FMVSS No. 116, fresh DOT 3 or 4 brake flu-
idB00126
Never let clutch fluid contact your
eyes because clutch fluid can be
harmful to your eyes. If clutch fluid
gets in your eyes, immediately flush
them thoroughly with clean water.
For safety, when performing this
work, wearing eye protection is ad-
visable.
Clutch fluid absorbs moisture
from the air. Any absorbed mois-
ture can cause improper clutch
operation.
If the vehicle requires frequent re-
filling, there may be a leak. If you
suspect a problem, have the vehi-
cle checked at your SUBARU
dealer.
Never use different brands of
clutch fluid together.
When clutch fluid is added, be
careful not to allow any dirt into
the tank.
Never splash the clutch fluid over
painted surfaces or rubber parts.
Alcohol contained in the clutch
fluid may damage them.
Be careful not to spill clutch fluid
when adding it. If clutch fluid
touches the exhaust pipe, it may
cause a bad smell, smoke, and/or
a fire. If clutch fluid gets on the ex-
haust pipe, be sure to wipe it off.
Avoid mixing DOT 3 and DOT 4
clutch fluids even if they are of the
same brand.

Maintenance and service 11-27
Brake booster
If the brake booster does not operate as
described in the following, have it checked
by your SUBARU dealer.
1. With the engine off, depress the brake
pedal several times, applying the same
pedal force each time. The distance the
pedal travels should not vary.
2. With the brake pedal depressed, start
the engine. The pedal should move slight-
ly down to the floor.
3. With the brake pedal depressed, stop
the engine and keep the pedal depressed
for 30 seconds. The pedal height should
not change.
4. Start the engine again and run for ap-
proximately one minute then turn it off.
Depress the brake pedal several times to
check the brake booster. The brake boost-
er operates properly if the pedal stroke de-
creases with each depression.
Brake pedal
Check the brake pedal free play and re-
serve distance according to the mainte-
nance schedule in the “Warranty and
Maintenance Booklet ”.
Checking the brake pedal free
play
1) 0.04 – 0.12 in (1.0 – 3.0 mm)
Stop the engine and firmly depress the
brake pedal several times. Lightly press
the brake pedal down with one finger to
check the free play with a force of less
than 2 lbs (10 N, 1 kg).
If the free play is not within proper specifi-
cation, contact your SUBARU dealer.
Checking the brake pedal re-
serve distance
1) More than 2.56 in (65 mm)
Depress the pedal with a force of approxi-
mately 66 lbs (294 N, 30 kg) and measure
the distance between the upper surface of
the pedal pad and the floor.
When the measurement is smaller than
the specification, or when the pedal does
not operate smoothly, contact with your
SUBARU dealer.1
B00377
1
B00378

11-28 Maintenance and service
Clutch pedal (MT vehicles)
Check the clutch pedal free play and re-
serve distance according to the mainte-
nance schedule in the “Warranty and
Maintenance Booklet ”.
Checking the clutch function
Check the clutch engagement and disen-
gagement.
1. With the engine idling, check that there
are no abnormal noises when the clutch
pedal is depressed, and that shifting into
1st or reverse feels smooth.
2. Start the vehicle by releasing the pedal
slowly to check that the engine and trans-
mission smoothly couple without any sign
of slippage.
Checking the clutch pedal
free play
1) 0.16 – 0.51 in (4.0 –13.0 mm)
Lightly press the clutch pedal down with
your finger until you feel resistance, and
check the free play.
If the free play is not within proper specifi-
cation, contact your SUBARU dealer.
Replacement of brake pad
and lining
The right front disc brake and the right rear
disc brake have audible wear indicators
on the brake pads. If the brake pads wear
close to their service limit, the wear indica-
tor makes a very audible scraping noise
when the brake pedal is applied.
If you hear this scraping noise each time
you apply the brake pedal, have the brake
pads serviced by your SUBARU dealer as
soon as possible.
1
B00377
700040

Maintenance and service 11-29
Breaking-in of new brake
pads and linings
When replacing the brake pad or lining,
use only genuine SUBARU parts. After re-
placement, the new parts must be broken
in as follows:
Brake pad and lining
While maintaining a speed of 30 to 40 mph
(50 to 65 km/h), step on the brake pedal
lightly. Repeat this five or more times.
Parking brake lining
1. Drive the vehicle at a speed of approx-
imately 22 mph (35 km/h).
2. With the parking brake release button
pushed in, pull the parking brake lever
SLOWLY and GENTLY. (Pulling with a
force of approximately 33 lbs [147 N, 15
kg].)
3. Drive the vehicle for approximately 220
yards (200 meters) in this condition.
4. Wait 5 to 10 minutes for the parking brake to cool down. Repeat this proce-
dure.
5. Check the parking brake stroke. If the
parking brake stroke is out of the specified
range, adjust it by turning the adjusting nut
located on the parking brake lever.
Parking brake stroke:
7
– 8 notches / 44 lbs (196 N, 20 kg)
Parking brake stroke
Check the parking brake stroke according
to the maintenance schedule in the “War-
ranty and Maintenance Booklet ”. When
the parking brake is properly adjusted,
braking power is fully applied by pulling
the lever up seven to eight notches gently
but firmly (approximately 44 lbs [196 N, 20
kg]). If the parking brake lever stroke is not
within the specified range, have the brake
system checked and adjusted at your
SUBARU dealer.
If you continue to drive despite the
scraping noise from the audible
brake pad wear indicator, it will re-
sult in the need for costly brake ro-
tor repair or replacement.
A safe location and situation should
be selected for break-in driving.
Pulling the parking brake lever too
forcefully may cause the rear
wheels to lock. To avoid this, be cer-
tain to pull the lever up slowly and
gently.
B00379

11-30 Maintenance and service
Tires and wheels
Types of tires
You should be familiar with type of tires
present on your vehicle.
The factory-fitted 17-inch tires on the
WRX-STI are summer tires. The factory-
fitted tires on other versions are all-sea-
son tires.
All season tires
All season tires are designed to provide
an adequate measure of traction, handling
and braking performance in year-round
driving including snowy and icy road con-
ditions. However all season tires do not of-
fer as much traction performance as win-
ter (snow) tires in heavy or loose snow or
on icy roads.
All season tires are identified by “ALL
SEASON ” and/or “M+S ” (Mud & Snow) on
the tire sidewall.
Summer tires
Summer tires are high-speed capability
tires best suited for highway driving under
dry conditions.
Summer tires are inadequate for driving
on slippery roads such as on snow-cov-
ered or icy roads.
If you drive your vehicle on snow-covered
or icy roads, we strongly recommend the use of winter (snow) tires.
When installing winter tires, be sure to re-
place all four tires.
Winter (snow) tires
Winter tires are best suited for driving on
snow-covered and icy roads. However
winter tires do not perform as well as sum-
mer tires and all season tires on roads oth-
er than snow-covered and icy roads.
Tire inspection
Check on a daily basis that the tires are
free from serious damage, nails, and
stones. At the same time, check the tires
for abnormal wear.
Contact your SUBARU dealer immediate-
ly if you find any problem.
NOTE
When the wheels and tires strike
curbs or are subjected to harsh treat-
ment as when the vehicle is driven on a
rough surface, they can suffer damage
that cannot be seen with the naked eye.
This type of damage does not become
evident until time has passed. Try not
to drive over curbs, potholes or on oth-
er rough surfaces. If doing so is un-
avoidable, keep the vehicle ’s speed
down to a walking pace or less, and ap-
proach the curbs as squarely as possi- ble. Also, make sure the tires are not
pressed against the curb when you
park the vehicle.
If you feel unusual vibration while
driving or find it difficult to steer the ve-
hicle in a straight line, one of the tires
and/or wheels may be damaged. Drive
slowly to the nearest authorized
SUBARU dealer and have the vehicle
inspected.
Tire pressures and wear
Maintaining the correct tire pressures
helps to maximize the tires ’ service lives
and is essential for good running perfor-
mance. Check and, if necessary, adjust
the pressure of each tire (including the
spare) at least once a month (for example,
during a fuel stop) and before any long
journey.

Maintenance and service 11-31
– CONTINUED –
Check the tire pressures when the tires
are cold. Use a pressure gauge to adjust
the tire pressures to the values shown on
the tire placard. The tire placard is located
on the door pillar on the driver
’s side.
Driving even a short distance warms up
the tires and increases the tire pressures.
Also, the tire pressures are affected by the
outside temperature. It is best to check tire
pressure outdoors before driving the vehi-
cle.
When a tire becomes warm, the air inside
it expands, causing the tire pressure to in-
crease. Be careful not to mistakenly re-
lease air from a warm tire to reduce its
pressure.
NOTE
The air pressure in a tire increases
by approximately 4.3 psi (30 kPa, 0.3
kgf/cm
2) when the tire becomes warm.
The tires are considered cold when
the vehicle has been parked for at least
three hours or has been driven less
than one mile (1.6 km).
Incorrect tire pressures detract from con-
trollability and ride comfort, and they
cause the tires to wear abnormally.
Correct tire pressure (tread worn
evenly)
Roadholding is good, and steering is re-
sponsive. Rolling resistance is low, so fuel
consumption is also lower.
B00164Do not let air out of warm tires to ad-
just pressure. Doing so will result in
low tire pressure.
B00050

11-32 Maintenance and service
Abnormally low tire pressure (tread
worn at shoulders)
Rolling resistance is high, so fuel con-
sumption is also higher.Abnormally high tire pressure (tread
worn in center)
Ride comfort is poor. Also, the tire magni-
fies the effects of road-surface bumps and
dips, possibly resulting in vehicle damage.
If the tire placard shows tire pressures for
the vehicle when fully loaded and for the
vehicle when towing a trailer, adjust the
tire pressures to the values that match
current loading conditions.
Wheel balance
Each wheel was correctly balanced when
your vehicle was new, but the wheels will
become unbalanced as the tires become
worn during use. Wheel imbalance caus-
es the steering wheel to vibrate slightly at
certain vehicle speeds and detracts from
the vehicle ’s straight-line stability. It can
also cause steering and suspension sys-
tem problems and abnormal tire wear. If
you suspect that the wheels are not cor-
rectly balanced, have them checked and
adjusted by your SUBARU dealer. Also
have them adjusted after tire repairs and
after tire rotation.
NOTE
Loss of correct wheel alignment* caus-
es the tires to wear on one side and re-
duces the vehicle ’s running stability.
B00051B00052
Driving at high speeds with exces-
sively low tire pressures can cause
the tires to deform severely and to
rapidly become hot. A sharp in-
crease in temperature could cause
tread separation, and destruction of
the tires. The resulting loss of vehi-
cle control could lead to an acci-
dent.

Maintenance and service 11-33
– CONTINUED –
Contact your SUBARU dealer if you no-
tice abnormal tire wear.
*: The suspension system is designed to hold
each wheel at a certain alignment (relative to
the other wheels and to the road) for optimum
straight-line stability and cornering perfor-
mance.
Wear indicators
1) New tread
2) Worn tread
3) Tread wear indicator
Each tire incorporates a tread wear indica-
tor, which becomes visible when the depth
of the tread grooves decreases to 0.063 in
(1.6 mm). A tire must be replaced when
the tread wear indicator appears as a solid
band across the tread.
NOTE
For safety, inspect tire tread regularly
and replace the tires before their tread
wear indicators become visible.
Tire rotation
Tire wear varies from wheel to wheel. To
maximize the life of each tire and ensure
that the tires wear uniformly, it is best to
rotate the tires every 7,500 miles (12,500
km). Rotating the tires involves switching
the front and rear tires on the right-hand
side of the vehicle and similarly switching
the front and rear tires on the left-hand
side of the vehicle. (Each tire must be kept
on its original side of the vehicle.)
Replace any damaged or unevenly worn
tire at the time of rotation. After tire rota-
tion, adjust the tire pressures and make
sure the wheel nuts are correctly tight-
ened.
After driving approximately 600 miles
(1,000 km), check the wheel nuts again
and retighten any nut that has become
loose.
Tire replacement
The wheels and tires are important and in-
tegral parts of your vehicle ’s design; they
cannot be changed arbitrarily. The tires fit-
ted as standard equipment are optimally
matched to the characteristics of the vehi-
cle and were selected to give the best pos-
sible combination of running performance,
ride comfort, and service life. It is essential
for every tire to have a size and construc-
tion matching those shown on the tire
1 2 3
B00327
When a tire’s tread wear indicator
becomes visible, the tire is worn be-
yond the acceptable limit and must
be replaced immediately. With a tire
in this condition, driving at high
speeds in wet weather can cause
the vehicle to hydroplane. The re-
sulting loss of vehicle control can
lead to an accident.
B00054