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G4M0744
2. AIR TIGHTNESS CHECK
Start engine, and run it for 1 to 2 minutes, then turn it off.
Depress brake pedal several times applying the same
pedal force as that used in ordinary braking operations.
The pedal stroke should be greatest on the 1st depression,
and it should become smaller with each successive
depression. If no change occurs in the pedal height while
in a depressed state, brake booster is faulty.
NOTE:
In the event of defective operation, inspect the condition
of the check valve and vacuum hose.
Replace them if faulty and conduct the test again.
If no improvement is observed, check precisely with
gauges.
G4M0914
3. OPERATION CHECK
1) With engine off, depress brake pedal several times
applying the same pedal force and make sure that the
pedal height does not vary with each depression of the
pedal.
2) With brake pedal depressed, start engine.
3) As engine starts, brake pedal should move slightly
toward the floor. If no change occurs in the pedal height,
brake booster is faulty.
NOTE:
If faulty, check precisely with gauges.
4. LOADED AIR TIGHTNESS CHECK
Depress brake pedal while engine is running, and turn off
engine while the pedal is still depressed. Keep the pedal
depressed for 30 seconds; if no change occurs in the pedal
height, brake booster is functioning normally; if the pedal
height increases, it is faulty.
NOTE:
If faulty, check precisely with gauges.
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6. Brake Booster
Page 762 of 2248

G4M0423
5. CHECKING WITH GAUGES
Connect gauges as shown in Figure. After bleeding air from
pressure gauges, proceed to each check.
G4M0746
6. AIR TIGHTNESS CHECK
1) Start engine and keep it running until a vacuum of 66.7
kPa (500 mmHg, 19.69 inHg) = point A is indicated on
vacuum gauge. Do not depress brake pedal.
2) Stop engine and watch the gauge. If the vacuum drop
range is less than 3.3 kPa (25 mmHg, 0.98 inHg) within 15
seconds after stopping engine, brake booster is functioning
properly.
If defective, the cause may be one of those listed below.
Check valve malfunction
Leak from vacuum hose
Leak from the shell jointed portion or stud bolt welded
portion
Damaged diaphragm
Leak from valve body seal and bearing portion
Leak from plate and seal assembly portion
Leak from poppet valve assembly portion
G4M0747
7. LOADED AIR TIGHTNESS CHECK
1) Start engine and depress brake pedal with pedal force
of 196 N (20 kg, 44 lb). Keep engine running until a vacuum
of 66.7 kPa (500 mmHg, 19.69 inHg) = point B is indicated
on vacuum gauge while the pedal is still depressed.
2) Stop engine and watch vacuum gauge.
If the vacuum drop range is less than 3.3 kPa (25 mmHg,
0.98 inHg) within 15 seconds after stopping engine, brake
booster is functioning properly.
If defective, refer to“AIR TIGHTNESS CHECK”described
above.
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6. Brake Booster
Page 763 of 2248

8. LACK OF BOOSTING ACTION CHECK
Turn off engine, and set the vacuum gauge reading at“0”.
Then, check the fluid pressure when brake pedal is
depressed. The pressure must be greater than the stan-
dard value listed below.
Brake pedal force 147N (15 kg, 33 lb) 294N (30kg, 66 lb)
Models without ABS and
TCS785 kPa
(8 kg/cm
2, 114 psi)2,158 kPa
(22 kg/cm2, 313 psi)
Models with ABS and
TCS588 kPa
(6 kg/cm
2, 85 psi)1,667 kPa
(17 kg/cm2, 242 psi)
9. BOOSTING ACTION CHECK
Set the vacuum gauge reading at 66.7 kPa (500 mmHg,
19.69 inHg) by running engine. Then, check the fluid pres-
sure when brake pedal is depressed. The pressure must
be greater than the standard value listed below.
Brake pedal force 147N (15 kg, 33 lb) 294N (30kg, 66 lb)
Models without ABS and
TCS5,492 kPa
(56 kg/cm
2, 796 psi)8,434 kPa
(86 kg/cm2, 1,223 psi)
Models with ABS and
TCS5,394 kPa
(55 kg/cm
2,782 psi)10,003 kPa
(102 kg/cm2, 1,450
psi)
D: HANDLING PRECAUTIONS
1) Be careful not to drop brake booster. Brake booster
should be discarded if it has been dropped.
2) Use special care when handling operating rod.
If excessive force is applied to operating rod, sufficient to
cause a change in the angle in excess of ±3°, it may result
in damage to the power piston cylinder.
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6. Brake Booster
Page 764 of 2248
G4M0425
3) Use care when placing brake booster on the floor.
CAUTION:
If external force is applied from above when brake
booster is placed in this position, the resin portion as
indicated by“P”, may be damaged.
G4M0424
4) Do not change the push rod length. If it has been
changed, reset the projected length“L”to the standard
length.
Standard:
L = 10 mm (0.39 in)
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6. Brake Booster
Page 765 of 2248

G4M0426
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.)
2) Pull out clamp to remove brake hose.
3) Remove clamp at strut and union bolt.
G4M0427
B: INSTALLATION
1. FRONT BRAKE HOSE
1) Route end of brake hose (on caliper side) through hole
in brake hose bracket at strut location.
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)
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.
7) While holding hexagonal part of brake hose fitting with
a wrench, tighten flare nut to the specified torque.
Tightening torque (Brake pipe flare nut):
15
+3
2N⋅m (1.5+0.3
0.2kg-m, 10.8+2.2
1.4ft-lb)
8) Bleed air from the brake system.
2. REAR BRAKE HOSE
1) Pass brake hose through the hole of bracket, and lightly
tighten flare nut to connect brake pipe.
2) Insert clamp upward to fix brake hose.
3) Perform the same procedures as before mentioned in
steps 7) and 8).
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7. Brake Hose
Page 766 of 2248

G4M0428
8. Hill Holder
A: REMOVAL
1) Drain brake fluid from reservoir of master cylinder.
2) Remove adjusting nut and cable clamp, and disconnect
PHV cable from cable bracket on engine.
3) Detach PHV cable from clips.
4) Remove cable clamp, and disconnect PHV cable from
PHV stay.
CAUTION:
Carefully protect boots and inner cable from damage
when disconnecting PHV cable.
5) Disconnect brake pipes from PHV.
CAUTION:
Pay attention not to drop brake fluid onto body
painting since it may dissolve paint.
Pay attention not to damage hexagonal head of flare
nut by using pipe wrench without fail.
6) Detach PHV along with support from side frame.
CAUTION:
Exercise utmost care to prevent foreign matter from
entering into PHV when removing it.
B: INSPECTION
Check up removed parts as follows, and replace defective
ones.
1) Check if boots of PHV cable are damaged or degraded,
and if inner cable is damaged or corroded.
2) Check if return spring is worn out, damaged or cor-
roded.
3) Confirm that rolling sound of ball is heard with PHV
inclined and lever rotates smoothly.
CAUTION:
Never disassemble PHV. Replace entire PHV assembly
if necessary.
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8. Hill Holder
Page 767 of 2248