Subaru Impreza 2004 User manual

FUJI HEAVY INDUSTRIES LTD. G1870GE5
2004 IMPREZA SERVICE MANUAL QUICK REFERENCE INDEX
CHASSIS SECTION
This service manual has been prepared
to provide SUBARU service personnel
with the necessary information and data
for the correct maintenance and repair
of SUBARU vehicles.
This manual includes the procedures
for maintenance, disassembling, reas-
sembling, inspection and adjustment of
components and diagnostics for guid-
ance of experienced mechanics.
Please peruse and utilize this manual
fully to ensure complete repair work for
satisfying our customers by keeping
their vehicle in optimum condition.
When replacement of parts during
repair work is needed, be sure to use
SUBARU genuine parts.
All information, illustration and specifi-
cations contained in this manual are
based on the latest product information
available at the time of publication
approval.
FRONT SUSPENSION FS
REAR SUSPENSION RS
WHEEL AND TIRE SYSTEM WT
DIFFERENTIALS DI
TRANSFER CASE TC
DRIVE SHAFT SYSTEM DS
ABS ABS
ABS (DIAGNOSTICS) ABS(diag)
BRAKE BR
PARKING BRAKE PB
POWER ASSISTED SYSTEM
(POWER STEERING) PS

BRAKE
BR
Page
1. General Description ....................................................................................2
2. Front Brake Pad ........................................................................................25
3. Front Disc Rotor ........................................................................................29
4. Front Disc Brake Assembly.......................................................................31
5. Rear Brake Pad.........................................................................................37
6. Rear Disc Rotor.........................................................................................40
7. Rear Disc Brake Assembly .......................................................................42
8. Rear Drum Brake Shoe.............................................................................47
9. Rear Drum Brake Drum ............................................................................49
10. Rear Drum Brake Assembly......................................................................50
11. Master Cylinder .........................................................................................53
12. Brake Booster ...........................................................................................55
13. Proportioning Valve...................................................................................59
14. Brake Fluid ................................................................................................60
15. Air Bleeding...............................................................................................62
16. Brake Hose ...............................................................................................65
17. Brake Pipe.................................................................................................67
18. Brake Pedal...............................................................................................68
19. Stop Light Switch ......................................................................................73
20. Hill Holder..................................................................................................75
21. General Diagnostics..................................................................................78

BR-2
BRAKE
General Description
1. General Description
A: SPECIFICATIONS
Model BASE, TS GX, RS, OBK WRX STi
Front
disc
brake
Size 14 inch type 15 inch type 16 inch type 17 inch type
Type Disc (Floating type, ventilated) Disc (Fixed type, ventilated)
Effective disc
diameter 210 mm (8.27 in) 228 mm (8.98 in) 255 mm (10.04 in) 268 mm (10.55 in)
Disc thickness ×
Outer diameter
24 ×260 mm
(0.94 ×10.24 in)
24 ×277 mm
(0.94 ×10.91 in)
24 ×294 mm
(0.94 ×11.57 in)
30 ×326 mm
(1.18 ×12.83 in)
Effective cylinder
diameter 57.2 mm (2.252 in) 42.8 mm (1.685 in) ×2 40.4 mm (1.591 in) ×4
40.0 mm ×2,
46.0 mm ×2
(1.575 in ×2,
1.811 in ×2)
Pad dimensions
(length ×width ×
thickness)
115.0 ×44.3 ×11.0
mm
(4.528 ×1.744 ×0.433
in)
117.8 ×50.5 ×11.0
mm
(4.638 ×1.988 ×0.433
in)
116.0 ×47.7 ×10.0
mm
(4.567 ×1.878 ×0.394
in)
129.8 ×60.5 ×9.2 mm
(5.110 ×2.382 ×0.362
in)
Clearance adjust-
ment Automatic adjustment
Rear
disc
brake
Size —14 inch type 15 inch type 17 inch type
Type —Disc (Floating type) Disc (Fixed type, ventilated)
Effective disc
diameter —230 mm (9.06 in) 261 mm (10.28 in) 268 mm (10.55 in)
Disc thickness ×
Outer diameter —10 ×266 mm
(0.39 ×10.47 in)
18 ×290 mm
(0.71 ×11.42 in)
20 ×316 mm
(0.79 ×12.44 in)
Effective cylinder
diameter —38.1 mm (1.500 in) 36.0 mm (1.417 in)
Pad dimensions
(length ×width ×
thickness)
—
89.4 ×33.7 ×9.0 mm
(3.520 ×1.327 ×0.354
in)
71.8 ×35.0 ×11.5 mm
(2.827 ×1.378 ×0.453
in)
74.8 ×45.0 ×9.0 mm
(2.945 ×1.772 ×0.354
in)
Clearance adjust-
ment —Automatic adjustment
Rear
drum
brake
Type Drum
(Leading-Trailing type) ———
Effective drum
diameter 228.6 mm (9 in) ———
Effective cylinder
diameter 17.5 mm (0.689 in) ———
Lining dimensions
(length ×width ×
thickness)
218.8 ×35.0 ×4.1 mm
(8.61 ×1.378 ×0.161
in)
———
Clearance adjust-
ment Automatic adjustment ———
Master
cylinder
Type Tandem
Effective diameter 23.81 mm (0.9374 in)
[25.4 mm (1 in)] 26.99 mm (1-1/16 in)
Reservoir type Sealed type
Brake fluid reser-
voir capacity 205 cm3(12.51 cu in)
Brake
booster
Type Vacuum suspended
Effective diameter
230 mm (9.06 in)
[180 + 205 mm
(7.09 + 8.07 in)]
205 + 230 mm
(8.07 + 9.06 in)

BR-3
BRAKE
General Description
[ ]: Model with ABS.
NOTE:
Refer to “PB section”for parking brake SPECIFICATIONS. <Ref. to PB-2, SPECIFICATIONS, General De-
scription.>
Propor-
tioning
valve
Split point 1,961 kPa
(20 kg/cm2, 285 psi) —
Reduce ratio 0.4 —
Brake line Dual circuit system
Brake fluid
C
AUTI
O
N:
•Avoid mixing brake fluid
of different brands to pre-
vent the fluid performance
from degrading.
•When brake fluid is sup-
plemented, be careful not to
allow any dust into the res-
ervoir.
•Use fresh DOT3 brake
fluid when replacing or
refilling the fluid.
FMVSS No. 116, DOT3
ITEM STANDARD SERVICE LIMIT
Front brake
Pad thickness
14″, 15″11 mm (0.43 in) 1.5 mm (0.059 in)
16″10 mm (0.39 in) 1.5 mm (0.059 in)
17″9.2 mm (0.362 in) 1.2 mm (0.047 in)
Disc thickness
Except
for 17″24 mm (0.94 in) 22 mm (0.87 in)
17″30 mm (1.18 in) 28 mm (1.10 in)
Disc runout —0.075 mm (0.0030 in)
Rear brake (Disc type)
Pad thickness
14″9.0 mm (0.354 in) 1.5 mm (0.059 in)
15″11.5 mm (0.452 in) 1.5 mm (0.059 in)
17″9.0 mm (0.354 in) 1.2 mm (0.047 in)
Disc thickness
14″10 mm (0.39 in) 8.5 mm (0.335 in)
15″18 mm (0.71 in) 16 mm (0.63 in)
17″20 mm (0.79 in) 18 mm (0.71 in)
Disc runout —0.07 mm (0.0028 in)
Rear brake (Drum type) Inside diameter 228.6 mm (9 in) 230.6 mm (9.08 in)
Lining thickness 4.1 mm (0.161 in) 1.5 mm (0.059 in)
Rear brake (Disc type
parking)
Inside diameter 170 mm (6.69 in) 171 mm (6.73 in)
Lining thickness 3.2 mm (0.126 in) 1.5 mm (0.059 in)
Parking brake Lever stroke 7 to 8 notches/196 N (20 kgf, 44 lb)
Model BASE, TS GX, RS, OBK WRX STi

BR-4
BRAKE
General Description
Brake pedal
force
Fluid pressure
BASE, TS GX, RS, OBK WRX STi
Without ABS With ABS
Brake
booster
Brake fluid pressure
without engine running
147 N
(15 kgf, 33 lb)
686 kPa
(7 kg/cm2,
100 psi)
588 kPa
(6 kg/cm2,
85 psi)
588 kPa
(6 kg/cm2, 85 psi)
294 N
(30 kgf, 66 lb)
1,961 kPa
(20 kg/cm2,
284 psi)
1,667 kPa
(17 kg/cm2,
242 psi)
1,471 kPa
(15 kg/cm2, 213 psi)
Brake fluid pressure
with engine running
and vacuum at 66.7
kPa (500 mmHg, 19.69
inHg)
147 N
(15 kgf, 33 lb)
5,982 kPa
(61 kg/cm2,
868 psi)
5,982 kPa
(61 kg/cm2,
868 psi)
5,296 kPa
(54 kg/cm2,
768 psi)
4,707 kPa
(48 kg/cm2,
683 psi)
4,021 kPa
(41 kg/cm2,
583 psi)
294 N
(30 kgf, 66 lb)
7,649 kPa
(78 kg/cm2,
1,109 psi)
8,434 kPa
(86 kg/cm2,
1,223 psi)
9,120 kPa
(93 kg/cm2, 1,323 psi)
8,336 kPa
(85 kg/cm2,
1,209 psi)
Brake pedal Free play 1 —3 mm (0.04 —0.12 in)
[Depress brake pedal pad with a force of less than 10 N (1 kgf, 2 lb).]

BR-5
BRAKE
General Description
B: COMPONENT
1. FRONT DISC BRAKE
•14 INCH TYPE
(1) Caliper body (9) Support (17) Bushing
(2) Air bleeder screw (10) Pad clip
(3) Guide pin (Green) (11) Outer shim Tightening torque: N·m (kgf-m, ft-lb)
(4) Pin boot (12) Inner shim T1: 8 (0.8, 5.8)
(5) Piston seal (13) Pad (Outside) T2: 18 (1.8, 13.0)
(6) Piston (14) Pad (Inside) T3: 37 (3.8, 27.5)
(7) Piston boot (15) Disc rotor T4: 80 (8.2, 59)
(8) Lock pin (Yellow) (16) Disc cover
BR-00377
(1) (2)
(3)
(9)
(10)
(11)
(11)
(15)
(16)
(12)
(12)
(13)
(14)
(5)
(6)
(7)
T3
T4
T2
T1
(4)
(4)
(17)
(8)

BR-6
BRAKE
General Description
•15 INCH TYPE
(1) Caliper body (9) Support (17) Bushing
(2) Air bleeder screw (10) Pad clip
(3) Guide pin (Green) (11) Outer shim Tightening torque: N·m (kgf-m, ft-lb)
(4) Pin boot (12) Inner shim T1: 8 (0.8, 5.8)
(5) Piston seal (13) Pad (Outside) T2: 27 (2.8, 19.9)
(6) Piston (14) Pad (Inside) T3: 37 (3.8, 27.5)
(7) Piston boot (15) Disc rotor T4: 80 (8.2, 59)
(8) Lock pin (Yellow) (16) Disc cover
BR-00378
(2)
(3)
T1
T3
(4)
(1)
(5)
(6)
(7)
(9)
(10)
(8)
(17)
(4)
(11)
(12)
(12)
T2
(15)
(11)
(16)
T4
(13)
(14)

BR-7
BRAKE
General Description
•16 INCH TYPE
(1) Housing (9) Piston boot (17) Spacer
(2) Air bleeder screw (10) Boot ring
(3) Caliper body (11) Outer shim Tightening torque: N·m (kgf-m, ft-lb)
(4) M clip (12) Inner shim T1: 8 (0.8, 5.8)
(5) Cross spring (13) Pad (Outside) T2: 18 (1.8, 13.0)
(6) Pad pin (14) Pad (Inside) T3: 80 (8.2, 59)
(7) Piston seal (15) Disc rotor
(8) Piston (16) Disc cover
BR-00379
(15)
(11)
(12)
(13)
(14)
(12)
(11)
(7)
(8)
(9)
(10)
(10)
(9)
(8)
(7)
(6)
(5)
(4)
(3)
(2)
T1
(1)
T3
(17)
(17)
T2
(16)

BR-8
BRAKE
General Description
•17 INCH TYPE
(1) Housing (8) Piston boot (15) Disc rotor
(2) Caliper body (9) Piston (16) Disc cover
(3) Air bleeder screw (10) Piston seal
(4) Guide plate (11) Pad shim (Outside) Tightening torque: N·m (kgf-m, ft-lb)
(5) Cross spring (12) Pad shim (Inside) T1: 18 (1.8, 13.0)
(6) Clip (13) Pad (Outside) T2: 20 (2.0, 14.5)
(7) Pad pin (14) Pad (Inside) T3: 155 (15.8, 114.3)
BR-00380
T2
T3
(15)
(5)
(4)
(6)
(14)
(3)
(2)
(1)
T1
(16)
(13)
(11)
(11) (10)
(10)
(9)
(9)
(8)
(8) (7)
(12)
(12)

BR-9
BRAKE
General Description
2. REAR DISC BRAKE
•14 INCH TYPE
(1) Caliper body (14) Shim (27) Primary shoe return spring
(2) Air bleeder screw (15) Shoe hold-down pin (28) Adjusting spring
(3) Guide pin (Green) (16) Cover (29) Adjuster
(4) Pin boot (17) Back plate (30) Shoe hold-down cup
(5) Piston seal (18) Retainer (31) Shoe hold-down spring
(6) Piston (19) Spring washer (32) Disc rotor
(7) Piston boot (20) Parking brake lever (33) Bushing
(8) Boot ring (21) Parking brake shoe (Secondary)
(9) Lock pin (Yellow) (22) Parking brake shoe (Primary) Tightening torque: N·m (kgf-m, ft-lb)
(10) Support (23) Strut T1: 8 (0.8, 5.8)
(11) Pad clip (24) Strut shoe spring T2: 37 (3.8, 27.5)
(12) Inner pad (25) Shoe guide plate T3: 52 (5.3, 38.3)
(13) Outer pad (26) Secondary shoe return spring
BR-00326
(1)
(2)
(3)
(4)
(4)
(33)
(10)
(14)
(11)
(11)
(18)
(19) (20) (21)
(22)
(23)
(24)
(25)
(26)
(27)
(28)
(29)
(30)
(31)
(32)
(12)
(13)
(14)
(17)
(16)
(15)
(5)
(6)
(7)
(8)
(9)
T2
T3
T3
T1

BR-10
BRAKE
General Description
•15 INCH TYPE
(1) Caliper body (14) Washer (27) Secondary shoe return spring
(2) Air bleeder screw (15) Cross spring (28) Primary shoe return spring
(3) Pad pin (16) Shoe hold-down pin (29) Adjusting spring
(4) Piston seal (17) Cover (30) Adjuster
(5) Piston (18) Back plate (31) Shoe hold-down cup
(6) Piston boot (19) Retainer (32) Shoe hold-down spring
(7) Boot ring (20) Spring washer (33) Disc rotor
(8) Pad clip (21) Parking brake lever
(9) Inner pad (22) Parking brake shoe (Secondary) Tightening torque: N·m (kgf-m, ft-lb)
(10) Outer pad (23) Parking brake shoe (Primary) T1: 8 (0.8, 5.8)
(11) Inner shim (24) Strut T2: 52 (5.3, 38.3)
(12) Outer shim (25) Strut shoe spring
(13) M clip (26) Shoe guide plate
BR-00327
T1
T2
T2
T2
(1)
(2)
(3)
(12)
(11)
(10)
(4)
(5)
(6)
(7)
(7)
(6)
(5)
(4)
(15)
(8)
(13)
(14)
(12)
(11)
(9)
(8)
(24)
(22)
(25)
(21)
(20)
(19)
(18)
(17)
(16)
(23)
(29)
(32)
(31)
(30)
(28)
(27)
(26)
(33)

BR-11
BRAKE
General Description
•17 INCH TYPE
(1) Caliper body (13) Shoe hold-down pin (25) Primary shoe return spring
(2) Air bleeder screw (14) Cover (26) Adjusting spring
(3) Guide plate (15) Back plate (27) Adjuster
(4) Cross spring (16) Retainer (28) Shoe hold-down cup
(5) Piston boot (17) Spring washer (29) Shoe hold-down spring
(6) Piston (18) Parking brake lever (30) Disc rotor
(7) Piston seal (19) Parking brake shoe (Secondary)
(8) Clip (20) Parking brake shoe (Primary) Tightening torque: N·m (kgf-m, ft-lb)
(9) Pad pin (21) Strut T1: 20 (2.0, 14.5)
(10) Pad shim (22) Strut shoe spring T2: 52 (5.3, 38.3)
(11) Pad (Outside) (23) Shoe guide plate T3: 65 (6.6, 47.9)
(12) Pad (Inside) (24) Secondary shoe return spring
BR-00281
T1
(5)
(5)
(4)
(6)
(6)
(3)
(2)
(1)
(18)
(14)
(25)
(26) (27)
(28)
(29)
(21)
(22)
(23)
(24)
(20)
(19)
(30)
(13)
(16) (17)
(15)
(12)
(11)
(10)
(10)
(9)
(8)
(7)
(7)
T3
T2

BR-12
BRAKE
General Description
3. REAR DRUM BRAKE
(1) Air bleeder cap (11) Upper shoe return spring (21) Lower shoe return spring
(2) Air bleeder screw (12) Retainer (22) Adjusting spring
(3) Boot (13) Washer (23) Drum
(4) Piston (14) Parking brake lever (24) Plug
(5) Cup (15) Brake shoe (Trailing)
(6) Spring (16) Brake shoe (Leading) Tightening torque: N·m (kgf-m, ft-lb)
(7) Wheel cylinder body (17) Shoe hold-down spring T1: 8 (0.8, 5.8)
(8) Pin (18) Cup T2: 10 (1.0, 7.2)
(9) Plug (19) Adjusting lever T3: 52 (5.3, 38.3)
(10) Back plate (20) Adjuster
T1
T2
T3
(1) (2)
(8)
(8)
(9)
(3)
(13)
(12)
(11)
(16)
(10)
(24)
(21)
(23)
(22)
(20)
(19)
(15)
(14)
(17)
(18)
(3)
(4)
(5)
(5)
(6)
(7)
(4)
BR-00004

BR-13
BRAKE
General Description
4. MASTER CYLINDER
•LHD MODEL
(1) Cap (6) Secondary piston Tightening torque: N·m (kgf-m, ft-lb)
(2) Filter (7) Cylinder body T1: 15 (1.5, 10.8)
(3) Reservoir tank (8) Cylinder pin
(4) Piston retainer (9) Seal
(5) Primary piston (10) Pin
BR-00153
T
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)

BR-14
BRAKE
General Description
•RHD MODEL
(1) Cap (6) Secondary piston Tightening torque: N·m (kgf-m, ft-lb)
(2) Filter (7) Cylinder body T1: 15 (1.5, 10.8)
(3) Reservoir tank (8) Cylinder pin
(4) Piston retainer (9) Seal
(5) Primary piston (10) Pin
BR-00196
T1
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)

BR-15
BRAKE
General Description
5. FRONT BRAKE PIPES AND HOSE
•LHD MODEL
(A) Model without ABS (B) Model with ABS (C) Model with ABS (with hill holder)
(1) Front brake pipe assembly (7) ABS control module and hydraulic
control unit (ABSCM&H/U)
Tightening torque: N·m (kgf-m, ft-lb)
(2) Proportioning valve T1: 15 (1.5, 10.8)
(3) Front brake hose RH (8) Bracket T2: 18 (1.8, 13.0)
(4) Front brake hose LH (9) Master cylinder T3: 32 (3.3, 23.6)
(5) Clamp (10) Hill holder
(6) Gasket (11) Two-way connector
BR-00283
(A) (B)
T1
T1
T1
T1
T1
T1
T2
T2
T2
T2
T3
T3
(8) (11)
(7)
(6)
(5)
(1)
(9)
(3)
(4)
(5)
(6)
(C)
T1
T1
T1
T1
T1
T2
T2
T2
T2
T3
T3
(11)
(8)
(7)
(6)
(5)
(10)
(9)
(3)
(4)
(5)
(6)
(1)
T2
(8)
(2)
T2
T3
T1 T1
(1)
(5)
(6) (3)
T2
T2
(6)
(4)
(5)
(9)
T3
T1
T1

BR-16
BRAKE
General Description
•RHD MODEL
(A) Model without ABS (B) Model with ABS (C) Model with ABS (With hill holder)
(1) Front brake pipe assembly (7) ABS control module and hydraulic
control unit (ABSCM&H/U)
Tightening torque: N·m (kgf-m, ft-lb)
(2) Proportioning valve T1: 15 (1.5, 10.8)
(3) Front brake hose RH (8) Bracket T2: 18 (1.8, 13.0)
(4) Front brake hose LH (9) Master cylinder T3: 32 (3.3, 23.6)
(5) Clamp (10) Hill holder
(6) Gasket (11) Two-way connector
BR-00284
(A) (B)
(1)
(8) (11)
(7)
(6)
(5)
(3)
(9)
(5)
(4)
(6)
T1
T1
T1
T1
T1
T1
T2
T2
T2
T2
T3
T3
(C)
T1
T1
T1
T1
T1
T1
T1
T2
T2
T2
T2
T3
T3
(1)
(11)
(8)
(5)
(7)
(6)
(3)
(9)
(10) (5)
(4)
(6)
T3
T2
T1
T1
T1
T2
T2
T3
(6) (6)
(5)
(9)
(8)
(2)
(6)
(3) (5)
(1)
(11)

BR-17
BRAKE
General Description
6. CENTER AND REAR BRAKE PIPES AND HOSES
(1) Center brake pipe assembly (6) Rear brake hose LH (Disc brake
model)
Tightening torque: N·m (kgf-m, ft-lb)
(2) Two-way connector T1: 15 (1.5, 10.8)
(3) Rear brake pipe assembly (7) Rear brake hose LH (Drum brake
model)
T2: 18 (1.8, 13.0)
(4) Rear brake hose RH (Disc brake
model) (8) Clamp
(5) Rear brake hose RH (Drum brake
model)
(9) Gasket
BR-00007
(5)
(8)
(9)
(8)
(3)
(6)
(2)
(1)
(8)
(8)
(8)
(7)
(9)
(4)

BR-18
BRAKE
General Description
7. BRAKE BOOSTER
•MODEL With ABS
•MODEL Without ABS
(1) Push rod (5) Filter (9) Valve body
(2) Return spring (6) Silencer (10) Plunger valve
(3) Reaction disc (7) Operating rod (11) Diaphragm plate
(4) Key (8) Poppet valve (12) Valve return spring
(1) Push rod (5) Plunger valve (9) Operating rod
(2) Return spring (6) Key (10) Silencer
(3) Diaphragm plate (7) Poppet valve (11) Filter
(4) Reaction disc (8) Valve return spring (12) Valve body
BR-00008
(11)
(10)
(12)
( 8 )
( 7 )
( 6 )
( 5 )
( 4 )
( 3 )
( 1 )
( 2 )
( 9 )
BR-00285
(3)
(5) (7) (8) (9)
(10)
(11)
(6)
(12)
(4)
(2)
(1)

BR-19
BRAKE
General Description
8. BRAKE PEDAL
•1.6 L MODEL
(A) LHD (B) RHD
(1) Stopper (10) Clutch pedal Tightening torque: N·m (kgf-m, ft-lb)
(2) Bushing (11) Clutch cable T1: 5.9 (0.6, 4.3)
(3) Pedal bracket (12) Clutch cable clamp T2: 8 (0.8, 5.8)
(4) Snap pin (13) Clip T3: 18 (1.8, 13.0)
(5) Brake pedal pad (14) Spring assist T4: 30 (3.1, 22.4)
(6) Brake pedal (15) Stop light switch T5: 33 (3.3, 24.3)
(7) Clevis pin (16) Brake pedal bracket ASSY
(8) Spring (17) Cover
(9) Clutch pedal pad (18) Protector
BR-00286
(17)
(16)
(15)
(1)
(18)
(5)
(6)
(4) (7)
T1
T2
T3
T4
T3
T2
(15)
(2)
(1)
(4)
(5)
(6)
(7)
(2)
(2) (8)
(13)
(1)
(2)
(8)
(14)
(10)
(9)
T2
(11)
(12)
(3)
(13) (14)
T3
T3
T5
T2
(A)
(B)