air bleeding SUBARU LEGACY 1995 Service User Guide

G4M0434
G4M0438
G4M0435
5) Install one end of a vinyl tube onto the air bleeder of and
insert the other end of the tube into a container to collect
the brake fluid.
6) Instruct your co-worker to depress the brake pedal
slowly two or three times and then hold it depressed.
7) Loosen bleeder screw approximately 1/4 turn until a
small amount of brake fluid drains into container, and then
quickly tighten screw.
8) Repeat steps 6) and 7) above until there are no air
bubbles in drained brake fluid and new fluid flows through
vinyl tube.
CAUTION:
Add brake fluid as necessary while performing the air
bleed operation, in order to prevent the tank from run-
ning short of brake fluid.
9) After completing the bleeding operation, hold brake
pedal depressed and tighten screw and install bleeder cap.
Tightening torque (Bleeder screw):
8±1 N⋅m (0.8±0.1 kg-m, 5.8±0.7 ft-lb)
10) Bleed air from each wheel cylinder using the same
procedures as described in steps 6) through 7) above.
11) Depress brake pedal with a force of approximately 294
N (30 kg, 66 lb) and hold it there for approximately 20 sec-
onds. At this time check pedal to see if it shows any
unusual movement.
Visually inspect bleeder screws and brake pipe joints to
make sure that there is no fluid leakage.
12) Install wheels, and drive vehicle for a short distance
between 2 to 3 km (1 to 2 miles) to make sure that brakes
are operating properly.
58
4-4SERVICE PROCEDURE
12. Brake Fluid Replacement

19. Air Bleeding (With TCS model)
A: RULES FOR EFFECTIVE BLEEDING
1) Pressure is not applied to suction pipe by depressing
brake pedal. When any of the following are performed,
bleed air from suction pipe by air bleeding control opera-
tion.
NOTE:
For TCS vehicle, suction pipe is installed between master
cylinder and hydraulic unit to allow flow of brake fluid
between them during ABS and TCS operation.
(1) When brake pipe is disconnected from master cyl-
inder.
(2) When brake pipe between hydraulic unit and mas-
ter cylinder is disconnected.
(3) When fluid is emptied from reservoir tank.
2) The time interval between two brake pedal operations
(from the time when the pedal is released to the time when
it is depressed another time) shall be approximately 3 sec-
onds.
3) The air bleeder on each brake shall be released for 1
to 2 seconds.
B: BLEEDING PROCEDURE WITH AIR
BLEEDING CONTROL
1. BLEEDING PROCEDURE
CAUTION:

The FMVSS No. 116, fresh DOT3 or 4 brake fluid
must be used.

Cover bleeder with waste cloth, when loosening it,
to prevent brake fluid from being splashed over sur-
rounding parts.

Avoid mixing different brands of brake fluid to pre-
vent degrading the quality of the fluid.

Be careful not to allow dirt or dust to get into the
reservoir tank.

During bleeding operation, keep the brake reserve
tank filled with brake fluid to eliminate entry of air.
NOTE:

Brake pedal operating must be very slow.

For convenience and safety, it is advisable to have two
man working.
G4M0434
1) Start air bleeding control operation. [W19D0].>
2) Make sure that there is no leak from joints and connec-
tions of the brake system.
3) Bleed air through front RH caliper by operating brake
pedal.
(1) Fit one end of vinyl tube into the air bleeder and put
the other end into a brake fluid container.
78
4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

(2) Slowly depress the brake pedal and keep it
depressed. Then, open the air bleeder to discharge air
together with the fluid.
Release air bleeder for 1 to 2 seconds.
Next, with the bleeder closed, slowly release the brake
pedal.
Repeat these steps until there are no more air bubbles
in the vinyl tube.
Allow 3 to 4 seconds between two brake pedal opera-
tions.
CAUTION:
Cover bleeder with waste cloth, when loosening it, to
prevent brake fluid from being splashed over sur-
rounding parts.
NOTE:
Brake pedal operating must be very slow.
4) Bleed air from suction pipe through front RH caliper.
(1) Open the air bleeder.
(2) Keep pressing TCS OFF switch for 20 seconds or
more.
NOTE:
Ensure no air comes out from air bleeder.
(3) Close the air bleeder.
5) Bleed air through front LH caliper by operating brake
pedal. This is the same procedure as step 3).
6) Bleed air from suction pipe through front LH caliper.
This is the same procedure as step 4).
7) Bleed air through front RH and LH calipers by operat-
ing brake pedal. This is the same procedure as step 3).
Repeat steps 3) to 7) until air does no longer comes out.
8) Tighten air bleeders securely when bubbles are visible.
Air bleeder tightening torque:
8±1 N⋅m (0.8±0.1 kg-m, 5.8±0.7 ft-lb)
9) Bleed air through rear LH and RH caliper by operating
brake pedal. This is the same procedure as step 3).
10) Tighten air bleeders securely when bubbles are vis-
ible.
Air bleeder tightening torque:
8±1 N⋅m (0.8±0.1 kg-m, 5.8±0.7 ft-lb)
79
4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

11) Operate FRO (Front Right Outlet) valve and RLO
(Rear Left Outlet) valve to bleed air from hydraulic unit
outlet circuit.
(1) Press TCS OFF switch while depressing brake
pedal.
(2) Make sure ABS warning light illuminates.
(3) Repeatedly depress and release brake pedal 10
times or more while pressing TCS OFF switch.
NOTE:

Air comes out from reservoir tank.
12) Operate FLO (Front Left Outlet) valve and RRO (Rear
Right Outlet) valve to bleed air from hydraulic unit outlet
circuit.
(1) Press TCS OFF switch while depressing brake
pedal.
(2) Make sure TCS warning light illuminates.
(3) Repeatedly depress and release brake pedal 10
times or more while pressing TCS OFF switch.
NOTE:

Air comes out from reservoir tank.

The operations in steps 11) and 12) above can be
switched with each other by operating brake pedal (stop
light switch) while pressing TCS OFF switch.

Repeat procedures 11) and 12) until air no longer comes
out of reservoir tank.
13) Perform these steps for the brakes connecting to the
secondary chamber of master cylinder, first, and then for
the ones connecting to primary chamber. With all proce-
dures completed, fully depress the brake pedal and keep
it in that position for approximately 20 seconds to make
sure that there is no leak evident in the entire system.
14) Turn ignition switch OFF.
15) Perform TCS sequence control.
80
4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

G4M0436
16) Check the pedal stroke.
While the engine is idling, depress the brake pedal with a
490 N (50 kg, 110 lb) load and measure the distance
between the brake pedal and steering wheel. With the
brake pedal released, measure the distance between the
pedal and steering wheel again. The difference between
the two measurements must be less than specified.
Specified pedal stroke:
With TCS
95 mm (3.74 in)
When depressing brake pedal with a 490 N (50 kg,
110 lb) load.
If the distance is more than specifications, there is a
possibility that air is in the brake line. Bleed air from the
brake line.
17) Turn ignition switch OFF.
18) Disconnect select monitor or diagnosis terminal.
19) Add brake fluid to the required level (MAX. level) of
reserve tank.
20) As a final step, test run the vehicle at low speed and
apply brakes relatively hard 2 to 3 times to ensure that
brakes provide normal braking action on all four wheels
without dragging and uneven braking.
2. CONDITIONS FOR AIR BLEEDING CONTROL
Stop light
switchTCS OFF
switchPump
motorTCS
valveFRO
RLOFLO
RROTCS
operating
indicator
lightABS
warning
lightTCS
warning
light
Air
bleeding
control is
operating.OFF ON ON Close Close Close ON ON ON
ON ON OFF Open Open Close ON ON OFF
ON ON OFF Open Close Open ON OFF ON
ON or OFF OFF OFF Open Close Close ON OFF OFF
Stops tem-
porarily.*——OFF Open Close Close OFF OFF OFF
Prohibited.——OFF Open Close Close OFF ON ON
*: When brake fluid level switch detects brake fluid in LOW level, control operation stops temporarily. After refilling brake fluid, operation
re-starts.
81
4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

3. CONDITIONS FOR COMPLETION OF AIR
BLEEDING CONTROL
When any of the following conditions occurs, ABS and TCS
warning lights illuminate. Air bleeding control stops, while
the ABS and TCS function will then stop. The brake sys-
tem functions as a conventional brake system.
1) When the speed of at least one wheel reaches 10 km/h
(6 MPH).
2) When terminal No. 4 is separated from diagnosis termi-
nal. (When select monitor is not used.)
3) When pump motor remains ON for two minutes.
4) When TCS valve remains open for two minutes.
5) When outlet valve remains closed for two minutes.
6) When malfunction is detected.
NOTE:
When a malfunction is detected the air bleeding operation
stops and the trouble codes are stored in memory.
B4M0082C
C: AIR BLEEDING CONTROL WITH
DIAGNOSIS CONNECTOR
1) Connect diagnosis terminals to terminal No. 4 of the
diagnosis connector beside driver’s seat heater unit.
B4M0621A
2) Start the engine while pushing TCS OFF switch.
NOTE:
Keep the TCS OFF switch depressed even after the engine
has started.
3) After ABS and TCS warning lights go out, depress
brake pedal within 0.5 seconds.
4) After ensuring TCS ON indicator illuminates, release
TCS OFF switch and brake pedal.
5) Air bleeding control operation starts.
82
4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

B4M0622A
D: AIR BLEEDING CONTROL WITH SELECT
MONITOR
1) Connect select monitor to data link connector beside
driver’s seat instrument panel lower.

1Data link connector (for Subaru select monitor and
OBD-II general scan tool)

2Data link connector (for Subaru select monitor)
NOTE:
When using data link connector
1above, use ST.
ST 498357200 ADAPTER CABLE
2) Start the engine.
3) Change select monitor to TCS mode by pressing the
function key.
B4M0623
4) Press FD3 ENT key.
B4M0624
5) When the message shown in the figure is displayed,
press ENT key.
B4M0625
6) Air bleeding control operation starts.
83
4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

B4M0626
7) Select monitor indicates that air bleeding control is now
operating.
B4M0627
8) When air bleeding control cannot be started (by system
malfunction, etc.), the message shown in the figure will be
displayed.
NOTE:
Read the trouble codes. Repair faulty parts.
84
4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

D: TROUBLE CODE 31, 33, 35, 37, 61 AND 62
—FAULTY INLET SOLENOID VALVE
CIRCUIT(S) AND TCS SOLENOID VALVE
CIRCUIT(S) IN HYDRAULIC UNIT—
DIAGNOSIS:

Faulty harness/connector

Faulty solenoid valve in hydraulic unit

Faulty ABS/TCS control module
TROUBLE SYMPTOM:

ABS does not operate.

TCS does not operate.

ABS sequence control does not operate.

TCS sequence control does not operate.

Air bleeding mode does not operate.
1. Check resistance of solenoid valve.
OK
Not OK
Replace hydraulic unit.
2. Check body short of solenoid valve.
OK
Not OK
Replace hydraulic unit.
3. Check body short of harness.
OK
Not OK
Repair harness.
4. Check harness between ABS/TCS control
module and hydraulic unit.
OK
Not OK
Repair harness/connector.
Replace ABS/TCS control module.




46
4-4bBRAKES
8. Diagnostics Chart with Trouble Code

E: TROUBLE CODE 32, 34, 36 AND 38
—FAULTY OUTLET SOLENOID VALVE
CIRCUIT(S) IN HYDRAULIC UNIT—
DIAGNOSIS:

Faulty harness/connector

Faulty solenoid valve in hydraulic unit

Faulty ABS/TCS control module
TROUBLE SYMPTOM:

ABS does not operate.

TCS does not operate.

ABS sequence control does not operate.

TCS sequence control does not operate.

Air bleeding mode does not operate.
1. Check resistance of solenoid valve.
OK
Not OK
Replace hydraulic unit.
2. Check body short of solenoid valve.
OK
Not OK
Replace hydraulic unit.
3. Check body short of harness.
OK
Not OK
Repair harness.
4. Check harness between ABS/TCS control
module and hydraulic unit.
OK
Not OK
Repair harness/connector.
Replace ABS/TCS control module.




50
4-4bBRAKES
8. Diagnostics Chart with Trouble Code