ABS SUBARU LEGACY 1999 Service Owner's Guide

5. Brake Booster
A: MODELS WITH ABS
B4M1121A
(1) Push rod
(2) Return spring
(3) Reaction disc
(4) Key(5) Filter
(6) Silencer
(7) Operating rod
(8) Poppet valve(9) Valve body
(10) Plunger valve
(11) Diaphragm plate
(12) Valve return spring
B: MODELS WITHOUT ABS
B4M1122A
(1) Push rod
(2) Return spring
(3) Diaphragm plate
(4) Reaction disc(5) Plunger valve
(6) Key
(7) Poppet valve
(8) Valve return spring(9) Operating rod
(10) Silencer
(11) Filter
(12) Valve body
13
[C5B0]4-4COMPONENT PARTS
5. Brake Booster

6. ABS System
A: SENSOR
B4M1441A
(1) G sensor
(2) Rear ABS sensor RH
(3) ABS spacer
(4) Rear ABS sensor LH(5) Front ABS sensor LH
(6) Front ABS sensor RHTightening torque: N´m (kg-m, ft-lb)
T1:
7.4±2.0 (0.75±0.2, 5.4±1.4)
T2:32±10 (3.3±1.0, 24±7)
14
4-4[C6A0]COMPONENT PARTS
6. ABS System

B: ABS CONTROL MODULE AND HYDRAULIC CONTROL UNIT (ABSCM&H/
U)
B4M1220B
(1) Stud bolt
(2) Damper
(3) ABS control module and hydrau-
lic control unit
(4) Front-LH outlet
(5) Secondary inlet(6) Front-RH outlet
(7) Primary inlet
(8) Rear-LH outlet
(9) Rear-RH outlet
(10) BracketTightening torque: N´m (kg-m, ft-lb)
T1:
18±5 (1.8±0.5, 13.0±3.6)
T2:29±7 (3.0±0.7, 21.7±5.1)
T3:32±10 (3.3±1.0, 24±7)
15
[C6B0]4-4COMPONENT PARTS
6. ABS System

D: ADJUSTMENT
1. SHOE CLEARANCE
1) Remove adjusting hole cover from back plate.
2) Turn adjusting screw using a slot-type screw-
driver until brake shoe is in close contact with disc
rotor.
G4M0416
3) Turn back (downward) adjusting screw 3 or 4
notches.
4) Install adjusting hole cover to back plate.
2. LEVER STROKE
1) Remove console box lid.
2) Forcibly pull parking brake lever 3 to 5 times.
3) Adjust parking brake lever by turning adjusting
nut until parking brake lever stroke is set at 7 to 8
notches with operating force of 196 N (20 kg, 44
lb).
B4M0050A
4) Tighten lock nut.
5) Install console box lid.
Lever stroke:
7 to 8 notches when pulled with a force
of 196 N (20 kg, 44 lb)
Tightening torque (Lock nut):
5.9
±1.5 N´m (0.60±0.15 kg-m, 4.3±1.1 ft-lb)
5. Master Cylinder
A: REMOVAL
1) Thoroughly drain brake fluid from reservoir
tank.
2) Disconnect fluid level indicator harness connec-
tor.
3) Remove brake pipes from master cylinder.
4) Remove master cylinder mounting nuts, and
take out master cylinder from brake booster.
CAUTION:
Be extremely careful not to spill brake fluid.
Brake fluid spilt on the vehicle body will harm
the painted surface; wipe it off quickly if spilt.
B: DISASSEMBLY
1. PRECAUTIONS FOR DISASSEMBLING
1) Remove mud and dirt from the surface of brake
master cylinder.
2) Prepare tools necessary for disassembly
operation, and arrange them neatly on work bench.
3) Clean work bench.
2. DISASSEMBLING PROCEDURE (2200
cc MODEL WITH ABS)
1) Remove pin with drift pin which secures reserve
tank to master cylinder.
B4M1446A
2) Remove cylinder pin with magnetic pick-up tool
while pushing in primary piston.
B4M1447A
37
[W5B2]4-4SERVICE PROCEDURE
5. Master Cylinder

D: ADJUSTMENT
1. SHOE CLEARANCE
1) Remove adjusting hole cover from back plate.
2) Turn adjusting screw using a slot-type screw-
driver until brake shoe is in close contact with disc
rotor.
G4M0416
3) Turn back (downward) adjusting screw 3 or 4
notches.
4) Install adjusting hole cover to back plate.
2. LEVER STROKE
1) Remove console box lid.
2) Forcibly pull parking brake lever 3 to 5 times.
3) Adjust parking brake lever by turning adjusting
nut until parking brake lever stroke is set at 7 to 8
notches with operating force of 196 N (20 kg, 44
lb).
B4M0050A
4) Tighten lock nut.
5) Install console box lid.
Lever stroke:
7 to 8 notches when pulled with a force
of 196 N (20 kg, 44 lb)
Tightening torque (Lock nut):
5.9
±1.5 N´m (0.60±0.15 kg-m, 4.3±1.1 ft-lb)
5. Master Cylinder
A: REMOVAL
1) Thoroughly drain brake fluid from reservoir
tank.
2) Disconnect fluid level indicator harness connec-
tor.
3) Remove brake pipes from master cylinder.
4) Remove master cylinder mounting nuts, and
take out master cylinder from brake booster.
CAUTION:
Be extremely careful not to spill brake fluid.
Brake fluid spilt on the vehicle body will harm
the painted surface; wipe it off quickly if spilt.
B: DISASSEMBLY
1. PRECAUTIONS FOR DISASSEMBLING
1) Remove mud and dirt from the surface of brake
master cylinder.
2) Prepare tools necessary for disassembly
operation, and arrange them neatly on work bench.
3) Clean work bench.
2. DISASSEMBLING PROCEDURE (2200
cc MODEL WITH ABS)
1) Remove pin with drift pin which secures reserve
tank to master cylinder.
B4M1446A
2) Remove cylinder pin with magnetic pick-up tool
while pushing in primary piston.
B4M1447A
37
[W5B2]4-4SERVICE PROCEDURE
5. Master Cylinder

3) Remove C-ring with C-ring pliers.
B4M1448A
4) Gradually supply compressed air via inlet of
master cylinder to force piston out.
CAUTION:
IPiston may jump out from master cylinder.
IDo not apply excessively high-pressure.
B4M1449
CAUTION:
IDo not disassemble the piston assembly;
otherwise, the spring set value may be
changed.
IUse brake fluid or methanol to wash inside
wall of cylinder, pistons and piston cups. Be
careful not to damage parts when washing. If
methanol is used for washing, do not dip rub-
ber parts, such as piston cups, in it for more
than 30 seconds; otherwise, they may become
swelled.
3. DISASSEMBLING PROCEDURE
(OTHER MODELS)
1) Remove reserve tank.
2) Remove cylinder pin. (only vehicle equipped
with ABS)
S4M0123A
3) Pry up the pawl and remove the piston retainer.
NOTE:
Piston may jump out from master cylinder.
S4M0124
4) Extract primary piston assembly and secondary
piston assembly.
CAUTION:
IDo not disassemble the piston assembly;
otherwise, the spring set value may be
changed.
IUse brake fluid or methanol to wash inside
wall of cylinder, pistons and piston cups. Be
careful not to damage parts when washing. If
methanol is used for washing, do not dip rub-
ber parts, such as piston cups, in it for more
than 30 seconds; otherwise, they may become
swelled.
C: INSPECTION
If any damage, deformation, wear, swelling, rust,
and other faults are found on the primary piston
assembly, secondary piston assembly, supply
valve stopper, or gasket, replace the faulty part.
CAUTION:
IThe primary and secondary pistons must be
replaced as complete assemblies.
IThe service limit of the clearance between
each piston and the master cylinder inner dia.
is 0.11 mm (0.0043 in).
IWhen handling parts, be extremely careful
not to damage or scratch the parts, or let any
foreign matter get on them.
38
4-4[W5B3]SERVICE PROCEDURE
5. Master Cylinder

D: ASSEMBLY
1. PRECAUTIONS FOR ASSEMBLING
1) When assembling, be sure to use recom-
mended brake fluid.
2) Ensure that the inside wall of cylinder, pistons,
and piston cups are free from dirt when assem-
bling.
3) Be extremely careful not to damage, scratch, or
dent cylinder inside wall, pistons, and piston cups.
4) Do not drop parts. Never attempt to use any
part that has been dropped accidentally.
2. ASSEMBLING OPERATION (2200 cc
MODEL WITH ABS)
1) Assembling piston assembly:
Apply recommended brake fluid to inside wall of
cylinder, and to outer surface of piston assembly,
and install piston assemblies carefully into cylinder.
2) Assemble cylinder pin by pushing in primary
piston.
3) Assemble plate and guide assembly.
4) Assemble C-ring.
CAUTION:
After assembling, ensure that the C-ring is fit-
ted securely in the ring grove.
5) Install seal to reservoir tank.
B4M1450A
6) Install pin with drift pins which secures reservoir
tank to master cylinder.
3. ASSEMBLING OPERATION (OTHER
MODELS)
1) Assembling piston assembly:
Apply recommended brake fluid to inside wall of
cylinder, and to outer surface of piston assembly,
and install piston assemblies carefully into cylinder.
2) Assembling cylinder pin:3) Press the pawl and install the piston retainer
into the master cylinder.
S4M0124
E: INSTALLATION
To install the master cylinder to the body, reverse
the sequence of removal procedure.
Tightening torque:
Master cylinder mounting nut
14
±4 N´m (1.4±0.4 kg-m, 10.1±2.9 ft-lb)
Piping flare nut
15
+3/þ2N´m (1.5+0.3/þ0.2kg-m, 10.8+2.2/þ1.4ft-lb)
CAUTION:
Be sure to use recommended brake fluid.
39
[W5E0]4-4SERVICE PROCEDURE
5. Master Cylinder

4. LACK OF BOOSTING ACTION CHECK
Turn off engine, and set the vacuum gauge read-
ing at ª0º. Then, check the fluid pressure when
brake pedal is depressed. The pressure must be
greater than the standard value listed below.
Brake pedal force147N (15 kg,
33 lb)294N (30kg, 66
lb)
Models without ABS785 kPa (8
kg/cm
2,114
psi)2,158 kPa (22
kg/cm2, 313 psi)
Models with ABS588 kPa (6
kg/cm
2, 85 psi)1,667 kPa (17
kg/cm2, 242 psi)
5. BOOSTING ACTION CHECK
Set the vacuum gauge reading at 66.7 kPa (500
mmHg, 19.69 inHg) by running engine. Then,
check the fluid pressure when brake pedal is
depressed. The pressure must be greater than the
standard value listed below.
Brake pedal force147N (15 kg,
33 lb)294N (30kg, 66
lb)
Models without ABS5,492 kPa (56
kg/cm
2, 796
psi)8,434 kPa (86
kg/cm2, 1,223 psi)
Models with ABS5,394 kPa (55
kg/cm
2,782 psi)10,003 kPa (102
kg/cm2, 1,450 psi)
7. Brake Hose
A: REMOVAL
1) Separate brake pipe from brake hose.
(Always use flare nut wrench and be careful not to
deform flare nut.)
G4M0426
2) Pull out clamp to remove brake hose.
3) Remove clamp at strut and union bolt.
B: INSTALLATION
1. FRONT BRAKE HOSE
1) Route end of brake hose (on caliper side)
through hole in brake hose bracket at strut loca-
tion.
2) Tighten end of brake hose at caliper using a
union bolt.
Tightening torque (Union bolt):
18
±3 N´m (1.8±0.3 kg-m, 13.0±2.2 ft-lb)
G4M0427
3) Secure middle fitting of brake hose to bracket at
strut location using a clamp.
4) Position disc in straight-forward direction and
route brake hose through hole in bracket on wheel
apron side.
CAUTION:
Be sure brake hose is not twisted.
5) Temporarily tighten flare nut to connect brake
pipe and hose.
6) Fix brake hose with clamp at wheel apron
bracket.
43
[W7B1]4-4SERVICE PROCEDURE
7. Brake Hose

4. LACK OF BOOSTING ACTION CHECK
Turn off engine, and set the vacuum gauge read-
ing at ª0º. Then, check the fluid pressure when
brake pedal is depressed. The pressure must be
greater than the standard value listed below.
Brake pedal force147N (15 kg,
33 lb)294N (30kg, 66
lb)
Models without ABS785 kPa (8
kg/cm
2,114
psi)2,158 kPa (22
kg/cm2, 313 psi)
Models with ABS588 kPa (6
kg/cm
2, 85 psi)1,667 kPa (17
kg/cm2, 242 psi)
5. BOOSTING ACTION CHECK
Set the vacuum gauge reading at 66.7 kPa (500
mmHg, 19.69 inHg) by running engine. Then,
check the fluid pressure when brake pedal is
depressed. The pressure must be greater than the
standard value listed below.
Brake pedal force147N (15 kg,
33 lb)294N (30kg, 66
lb)
Models without ABS5,492 kPa (56
kg/cm
2, 796
psi)8,434 kPa (86
kg/cm2, 1,223 psi)
Models with ABS5,394 kPa (55
kg/cm
2,782 psi)10,003 kPa (102
kg/cm2, 1,450 psi)
7. Brake Hose
A: REMOVAL
1) Separate brake pipe from brake hose.
(Always use flare nut wrench and be careful not to
deform flare nut.)
G4M0426
2) Pull out clamp to remove brake hose.
3) Remove clamp at strut and union bolt.
B: INSTALLATION
1. FRONT BRAKE HOSE
1) Route end of brake hose (on caliper side)
through hole in brake hose bracket at strut loca-
tion.
2) Tighten end of brake hose at caliper using a
union bolt.
Tightening torque (Union bolt):
18
±3 N´m (1.8±0.3 kg-m, 13.0±2.2 ft-lb)
G4M0427
3) Secure middle fitting of brake hose to bracket at
strut location using a clamp.
4) Position disc in straight-forward direction and
route brake hose through hole in bracket on wheel
apron side.
CAUTION:
Be sure brake hose is not twisted.
5) Temporarily tighten flare nut to connect brake
pipe and hose.
6) Fix brake hose with clamp at wheel apron
bracket.
43
[W7B1]4-4SERVICE PROCEDURE
7. Brake Hose

11. Air Bleeding
A: GENERAL RULES FOR
EFFECTIVE BLEEDING
1) Start with the brakes (wheels) connecting to the
secondary chamber of the master cylinder.
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 seconds.
3) The air bleeder on each brake shall be released
for 1 to 2 seconds.
B: BLEEDING PROCEDURE
CAUTION:
IThe FMVSS No. 116, fresh DOT3 or 4 brake
fluid must be used.
ICover bleeder with waste cloth, when loos-
ening it, to prevent brake fluid from being
splashed over surrounding parts.
IAvoid mixing different brands of brake fluid
to prevent degrading the quality of the fluid.
IBe careful not to allow dirt or dust to get into
the reservoir tank.
NOTE:
IDuring bleeding operation, keep the brake
reserve tank filled with brake fluid to eliminate entry
of air.
IBrake pedal operating must be very slow.
IFor convenience and safety, it is advisable to
have two men working.
1) Make sure that there is no leak from joints and
connections of the brake system.2) Fit one end of vinyl tube into the air bleeder and
put the other end into a brake fluid container.
G4M0434
G4M0435
3) 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
operations.
CAUTION:
Cover bleeder with waste cloth, when loosen-
ing it, to prevent brake fluid from being
splashed over surrounding parts.
NOTE:
Brake pedal operating must be very slow.
4) Tighten air bleeder securely when no air
bubbles are visible.
Air bleeder tightening torque:
8
±1 N´m (0.8±0.1 kg-m, 5.8±0.7 ft-lb)
5) Perform these steps for the brakes connecting
to the secondary chamber of master cylinder, first,
and then for the ones connecting to primary cham-
ber. With all procedures 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.
6) Perform sequence control. (With ABS model)
<Ref. to 4-4 [W15D0].>
48
4-4[W11A0]SERVICE PROCEDURE
11. Air Bleeding