Infiniti G37 Coupe. Manual - part 249

BR-34

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BRAKE BOOSTER

• Be careful not to damage brake booster stud bolt threads. If brake booster is tilted during installa-

tion, the dash panel may damage the threads.

•  Never deform or bend the brake tubes when installing the brake booster.
• Always use a new gasket between the brake booster and the dash panel.
• Replace the clevis pin if it is damaged. Refer to 

BR-20, "Inspection and Adjustment"

.

• Install the brake pedal assembly and brake booster mounting nuts, and tighten it to the specified

torque.

• After installation, perform the air bleeding. Refer to 

BR-12, "Bleeding Brake System"

.

CAUTION:

Never reuse drained brake fluid.

Inspection and Adjustment

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INSPECTION AFTER REMOVAL

Input Rod Length Inspection

1.

Loosen the lock nut (1) and adjust the input rod (2) to the speci-
fied length (B).

2.

Tighten the lock nut to the specified torque.

INSPECTION AFTER INSTALLATION

Operation

Depress the brake pedal several times at 5-second intervals with the
engine stopped. Start the engine with the brake pedal fully
depressed. Check that the clearance between brake pedal and dash
lower pane decreases.
NOTE:
A slight impact with a small click may be felt on the pedal when the
brake pedal is fully depressed. This is a normal phenomenon due to
the brake system operation.

Air Tight

• Run the engine at idle for 1 minute to apply vacuum to the brake

booster, and stop the engine. Then depress the brake pedal sev-
eral times at 5-second intervals until the accumulated vacuum is
released to atmospheric pressure. Check that the clearance
between brake pedal and dash lower panel gradually increases (A

→

 B 

→

 C) each time the brake pedal is depressed when perform-

ing this operation.

Standard

Input rod length (B)

: Refer to 

BR-63, "Brake 

Booster"

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BRAKE BOOSTER

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• Depress the brake pedal with the engine running. Then stop the

engine while holding down the brake pedal. Check that the brake
pedal stroke does not change after holding down the brake pedal
for 30 seconds or more.
NOTE:
A slight impact with a small click may be felt on the pedal when the
brake pedal is fully depressed. This is a normal phenomenon due
to the brake system operation.

ADJUSTMENT AFTER INSTALLTION

Perform the brake pedal adjustment after installing the brake pedal assembly. Refer to 

BR-7, "Inspection and

Adjustment"

.

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BR-36

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BRAKE BOOSTER PRESSURE SENSOR

BRAKE BOOSTER PRESSURE SENSOR

Exploded View

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Removal and Installation

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REMOVAL

1.

Remove master cylinder cover.

2.

Remove brake booster pressure sensor.

3.

Remove vacuum hose.

INSTALLATION

Note the following, installation is the reverse order of removal. 

CAUTION:

• Insert vacuum hose at least 25 mm (0.98 in) (A).
• Never use lubricating oil during assembly.
• Face the marking side vehicle front when assembling (brake

booster side).

• Face the marking side connector when assembling (brake

booster pressure sensor side).

Inspection

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INSPECTION AFTER REMOVAL

• Check for correct assembly, damage and deterioration.
• Check for brake booster pressure sensor. Refer to 

EC-352, "Component Inspection"

.

1.

Brake booster

2.

Clamp

3.

Vacuum hose

4.

Brake booster pressure sensor

A.

Paint mark

Refer to 

GI-4, "Components"

 for symbols in the figure.

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VACUUM LINES

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VACUUM LINES

Exploded View

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Removal and Installation

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REMOVAL

1.

Remove the engine cover. Refer to 

EM-24, "Exploded View"

.

2.

Remove the cowl top. Refer to 

EXT-21, "Exploded View"

.

3.

Remove the vacuum hose and tube.

INSTALLATION

Installation is the reverse order of removal.

CAUTION:

• Because vacuum hose contains a check valve, it must be

installed in the correct position. Refer to the stamp to confirm
correct installation. Brake booster will not operate normally if
the hose is installed in the wrong direction. 

• Insert vacuum hose at least 24 mm (0.94 in) (A).
• Never use lubricating oil during assembly.
• Face the marking side up when assembling.

Inspection

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INSPECTION AFTER REMOVAL

Appearance

Check for correct assembly, damage and deterioration.

Check Valve Airtightness

1.

Grommet

2.

Clamp

3.

Vacuum hose (built in check valve)

4.

Vacuum piping

5.

Vacuum hose

A.

To intake manifold

B.

Paint mark

C.

Stamp indicating engine direction

D.

Stamp indicating grommet installa-
tion position

E.

To brake booster

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