Brake booster INFINITI QX56 2008 Factory Service Manual

QUICK REFERENCE CHART: QX56
2008
Brake SpecificationsINFOID:0000000006237755
Unit: mm (in)
Brake PedalINFOID:0000000006237756
Unit: mm (in)
CAUTION:
When equipped with adjustable pedal, the pedal must be in the forward most position (closest to the floor) for pedal height
adjustment. Front brake Brake model AD41VA
Rotor outer diameter × thickness 350 x 30 (13.78 x 1.181)
Pad Length × width × thickness 151.6 x 56.5 x 12.0 (5.97 x 2.22 x 0.476)
Cylinder bore diameter 50.8 (2.00)
Rear brake Brake model AD14VE Rotor outer diameter × thickness 320 x 14 (12.60 x 0.551)
Pad Length × width × thickness 83.0 x 33.0 x 12.0 (3.268 x 1.299 x 0.472)
Cylinder bore diameter 48 (1.89)
Control valve Valve model Electric brake force distribution
Brake booster Booster model C215T
Diaphragm diameter 215 (8.46)
Pedal free height (H) with pedal in forward most position 182.3 - 192.3 (7.18 - 7.57)
Pedal travel (T) 153.3 (6.04)
Stop lamp switch and ASCD cancel switch threaded end to brake pedal bracket gap 0.74 - 1.96 (0.029 - 0.077)
ALFIA0149ZZ

BR-1
BRAKES
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SECTION BR
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BR
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CONTENTS
BRAKE SYSTEM
PRECAUTION ....... ........................................3
PRECAUTIONS .............................................. .....3
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
3
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect ............................... ......
3
Precaution for Brake System ....................................4
PREPARATION ............................................5
PREPARATION .............................................. .....5
Special Service Tool ........................................... ......5
Commercial Service Tool ..........................................5
FUNCTION DIAGNOSIS ...............................6
NOISE, VIBRATION AND HARSHNESS
(NVH) TROUBLESHOOTING ........................ .....
6
NVH Troubleshooting Chart ................................ ......6
BASIC INSPECTION ....................................7
FRONT DISC B RAKE .................................... .....7
BRAKE PAD .......................................................... ......7
BRAKE PAD : Inspection ..........................................7
DISC ROTOR ......................................................... ......7
DISC ROTOR : Inspection ........................................7
REAR DISC BRAKE ...................................... .....9
BRAKE PAD .......................................................... ......9
BRAKE PAD : Inspection ..........................................9
DISC ROTOR ......................................................... ......9
DISC ROTOR : Inspection ........................................9
BRAKE BOOSTER ............................................10
Inspection ............................................................ ....10
VACUUM LINES ............................................. ....11
Inspection ............................................................ ....11
BRAKE MASTER CYLINDER ..........................12
On Board Inspection ................................................12
BRAKE TUBE AND HOSE ...............................13
Hydraulic Circuit ......................................................13
FRONT BRAKE ..................................................... ....13
FRONT BRAKE : Inspection ......................... ...........13
REAR BRAKE ........................................................ ....14
REAR BRAKE : Inspection ........................ ..............14
ON-VEHICLE MAINTEN ANCE ....................15
BRAKE PEDAL .................................................15
Inspection and Adjustment .................................. ....15
BRAKE FLUID ..................................................17
On Board Inspection ............................................ ....17
Drain and Refill ........................................................17
Bleeding Brake System ...........................................17
ON-VEHICLE REPAIR .................................19
BRAKE PEDAL .................................................19
Removal and Installation ..................................... ....19
BRAKE TUBE AND HOSE ...............................21
Hydraulic Circuit ......................................................21
Removal and Installation of Front Brake Piping
and Brake Hose .......................................................
21
Removal and Installation of Rear Brake Piping
and Brake Hose .......................................................
22
Inspection After Installation .....................................23
BRAKE MASTER CYLINDER ..........................25
Removal and Installation .........................................25
BRAKE BOOSTER ...........................................26
Removal and Installation ..................................... ....26
VACUUM LINES ...............................................28
Revision: March 2010 2008 QX56

BR-2
Removal and Installation ........................................28
FRONT DISC BRAKE ........................................29
Exploded View of Brake Pads ............................. ...29
Removal and Installation of Brake Pads .................29
Brake Burnishing Procedure ...................................30
Exploded View of Brake Caliper .............................31
Removal and Installation of Brake Caliper and Ro-
tor ...........................................................................
31
REAR DISC BRAKE ..........................................34
Exploded View of Brake Pads ............................. ...34
Removal and Installation of Brake Pad ..................34
Brake Burnishing Procedure ...................................35
Exploded View of Brake Caliper .............................35
Removal and Installation of Brake Caliper and
Disc Rotor ............................................................ ...
36
DISASSEMBLY AND ASSEMBLY .............37
BRAKE MASTER CYLINDER ........................ ...37
Disassembly and Assembly ................................. ...37
FRONT DISC BRAKE .......................................39
Disassembly and Assembly ................................. ...39
REAR DISC BRAKE ....................................... ...42
Disassembly and Assembly ................................. ...42
SERVICE DATA AND SPECIFICATIONS
(SDS) .......... ................................. ...............
45
SERVICE DATA AND SPECIFICATIONS
(SDS) .............................................................. ...
45
General Specification ........................................... ...45
Brake Pedal ............................................................45
Brake Booster .........................................................46
Check Valve ............................................................46
Front Disc Brake .....................................................46
Rear Disc Brake ......................................................46
Revision: March 2010 2008 QX56

BR-10
< BASIC INSPECTION >
BRAKE BOOSTER
BRAKE BOOSTER
InspectionINFOID:0000000004894486
OPERATION
With engine stopped, change vacuum to atmospheric pressure by
depressing brake pedal several times. Then with brake pedal fully
depressed, start engine and when vacuum pressure reaches the
standard, make sure that clearance between brake pedal and floor
panel decreases.
AIR TIGHT
• Run engine at idle for approximately 1 minute, and stop it afterapplying vacuum to booster. Depress brake pedal normally to
change vacuum to atmospheric pressure. Make sure that distance
at intervals of 5 seconds between brake pedal and floor panel
gradually increases.
• Depress brake pedal while engine is running, and stop engine with pedal depressed. The pedal stroke should not change after holding pedal down for 30 seconds.
BRA0037D
SBR365AA
Revision: March 2010 2008 QX56

VACUUM LINESBR-11
< BASIC INSPECTION >
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VACUUM LINES
InspectionINFOID:0000000004894487
VISUAL INSPECTION
Check for improper assembly, damage and de terioration. Replace as necessary.
CHECK VALVE INSPECTION
Airtightness Inspection
Use a suitable vacuum pump to check. Connect to brake booster
side of check valve.
Check valve specification : Refer to BR-46, "
Check
Va l v e".
LFIA0217E
Revision: March 2010 2008 QX56

BR-12
< BASIC INSPECTION >
BRAKE MASTER CYLINDER
BRAKE MASTER CYLINDER
On Board InspectionINFOID:0000000004894488
LEAK INSPECTION
Check for leaks at master cylinder to brake booster attachment point, reservoir tank, and brake tube connec-
tions.
Revision: March 2010 2008 QX56

BRAKE TUBE AND HOSEBR-13
< BASIC INSPECTION >
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BRAKE TUBE AND HOSE
Hydraulic CircuitINFOID:0000000004894489
CAUTION:
• All hoses and piping (tubes) must be fr ee from excessive bending, twisting and pulling.
• Make sure there is no interference with other parts when turning the steering wheel both clockwise
and counterclockwise.
• The brake piping is an important safety part. If a brake fluid leak is detected, always disassemble the
parts. Replace applicable part with a new one, if necessary.
• Be careful not to splash brake fluid on painted areas; it may cause paint damage. If brake fluid is
splashed on painted areas, wash it away with water immediately.
• Do not bend or twist brake hose sharply, or strongly pull it.
• When removing components, cover connections so that no dirt, dust, or other foreign matter gets in.
• Refill with new specified brake fluid. Refer to MA-12, "
Fluids and Lubricants".
• Do not reuse drained brake fluid.
FRONT BRAKE
FRONT BRAKE : InspectionINFOID:0000000004894490
INSPECTION AFTER REMOVAL
CAUTION:
Brake tubes and hoses are important safety parts. Always disassemble the parts and retighten their fit-
tings, if a brake fluid leak is det ected. Replace applicable part with a new one, if damaged part is
detected.
1. Actuator 2. Master cylinder3. Brake booster
4. Connector A. Union bolt
18.2 N·m (1.9 kg-m, 13 ft-lb) B. Flare nut M12
18.2 N·m (1.9 kg-m, 13 ft-lb)
C. Flare nut M10 13.0 N·m (1.3 kg-m, 10 ft-lb)
AWFIA0411ZZ
Revision: March 2010 2008 QX56

BR-20
< ON-VEHICLE REPAIR >
BRAKE PEDAL
3. Disconnect the adjustable brake pedal cable from the adjustablepedal electric motor.
• Unlock (1) then pull (2) the adjustable brake pedal cable to dis-connect it from the adjustable pedal electric motor as shown.
4. Remove snap pin and clevis pin from the clevis of brake booster.
5. Remove brake pedal assembly nuts and remove the brake pedal assembly. • Temporarily install the brake pedal assembly nuts by hand to support the brake booster.
WARNING:
Do not bend the brake tubing.
CAUTION:
• Before removal and installation, the accelerator and brake pedals must be in the forward mostposition (closest to the floor). This is to align the base position of the accelerator and brake ped-
als.
• Do not disassemble the brake pedal adjusting mechanism.
• Avoid damage from dropping th e brake pedal assembly during handling.
• Keep the brake pedal assembly away from water.
INSPECTION AFTER REMOVAL
Check the brake pedal assembly for the following items:
• Crack or deformation of clevis pin stopper
• Clevis pin deformation
• Crack of any welded portion of the brake pedal assembly
• Brake pedal bend or deformation
INSTALLATION
Installation is in the reverse order of removal.
• Check the brake pedal for smooth operation. Ther e should be no binding or sticking when applying or
releasing the brake pedal.
• Check the brake pedal adjustable feature for smooth operation. There should be no binding or sticking when adjusting the brake pedal forward or backward.
• After installing the brake pedal assembly, be sure to adjust it. Refer to BR-15, "
Inspection and Adjustment".
LBIA0374E
SBR997
Revision: March 2010 2008 QX56

BRAKE TUBE AND HOSEBR-21
< ON-VEHICLE REPAIR >
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BRAKE TUBE AND HOSE
Hydraulic CircuitINFOID:0000000004894506
CAUTION:
• All hoses and piping (tubes) must be fr ee from excessive bending, twisting and pulling.
• Make sure there is no interference with other parts when turning the steering wheel both clockwise
and counterclockwise.
• The brake piping is an important safety part. If a brake fluid leak is detected, always disassemble the
parts. Replace applicable part with a new one, if necessary.
• Be careful not to splash brake fluid on painted areas; it may cause paint damage. If brake fluid is
splashed on painted areas, wash it away with water immediately.
• Do not bend or twist brake hose sharply, or strongly pull it.
• When removing components, cover connections so that no dirt, dust, or other foreign matter gets in.
• Refill with new specified brake fluid. Refer to MA-12, "
Fluids and Lubricants".
• Do not reuse drained brake fluid.
Removal and Installation of Fr ont Brake Piping and Brake HoseINFOID:0000000004894507
REMOVAL
1. Remove front wheel and tire using power tools.
2. Remove brake reservoir cap.
1. Actuator 2. Master cylinder3. Brake booster
4. Connector A. Union bolt
18.2 N·m (1.9 kg-m, 13 ft-lb) B. Flare nut M12
18.2 N·m (1.9 kg-m, 13 ft-lb)
C. Flare nut M10 13.0 N·m (1.3 kg-m, 10 ft-lb)
AWFIA0411ZZ
Revision: March 2010 2008 QX56

BRAKE MASTER CYLINDERBR-25
< ON-VEHICLE REPAIR >
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BRAKE MASTER CYLINDER
Removal and InstallationINFOID:0000000004894510
REMOVAL
CAUTION:
• Be careful not to splash brake fluid on painted areas; it may cause paint damage. If brake fluid is
splashed on painted areas, wash it away with water immediately.
• Before removing brake master cylinder, depress the brake pedal 5-6 times with the key OFF to deplete vacuum in the booster.
1. Remove brake reservoir cap.
2. Disconnect harness connectors for fluid level sensor, front and rear pressure sensors.
3. Using suitable tool, disconnect brake tube from master cylinder assembly.
4. Remove master cylinder assembly nuts, and remove master cylinder assembly.
INSTALLATION
Installation is in the reverse order of removal.
• Refill brake fluid and bleed air. Refer to BR-17, "
Bleeding Brake System".
CAUTION:
• Refill with new brake fluid. Refer to MA-12, "
Fluids and Lubricants".
• Do not reuse drained brake fluid.
• Adjust brake pedal. Refer to BR-15, "
Inspection and Adjustment".
1. Reservoir cap 2. Fluid level sensor 3. Grommet
4. Master cylinder assembly 5. Rear pressure sensor6. Front pressure sensor
7. Seal 8. Reservoir tankB. Brake fluid
R. Rubber grease
AWFIA0415GB
Revision: March 2010 2008 QX56