ABS NISSAN PATROL 1998 Y61 / 5.G Brake System Workshop Manual

BRAKE SYSTEM
SECTION
BR
CONTENTS
PRECAUTIONS AND PREPARATION ............................1
Supplemental Restraint System (SRS) ``AIR
BAG'' and ``SEAT BELT PRE-TENSIONER''...............1
Precautions for Brake System .....................................1
Commercial Service Tools ...........................................1
NOISE, VIBRATION AND HARSHNESS (NVH)
TROUBLESHOOTING .....................................................2
NVH Troubleshooting Chart.........................................2
CHECK AND ADJUSTMENT ..........................................3
Checking Brake Fluid Level.........................................3
Checking Brake Line ...................................................3
Changing Brake Fluid ..................................................3
Bleeding Brake System ...............................................4
BRAKE HYDRAULIC LINE/CONTROL VALVE ..............5
Brake Hydraulic Line ...................................................5
Load Sensing Valve .....................................................6
BRAKE PEDAL AND BRACKET ..................................10
Removal and Installation ...........................................10
Inspection...................................................................10
Adjustment .................................................................10
MASTER CYLINDER .....................................................12
Removal .....................................................................12
Disassembly...............................................................13
Inspection...................................................................13
Assembly ...................................................................13
Installation ..................................................................14
BRAKE BOOSTER ........................................................15
Brake Booster ............................................................15
VACUUM PIPING (LHD models) ..................................17
Vacuum Hose ............................................................17
VACUUM PIPING (RHD models) .................................18
Vacuum Hose ............................................................18
VACUUM PIPING ...........................................................19
VACUUM PUMP ............................................................20
Removal and Installation ...........................................20
FRONT DISC BRAKE ...................................................21
Pad Replacement ......................................................21
Removal .....................................................................23
Disassembly...............................................................23 Inspection Ð Caliper .................................................23
Inspection Ð Rotor ....................................................24
Assembly ...................................................................24
Installation ..................................................................24
REAR DISC BRAKE ......................................................25
Pad Replacement ......................................................25
Removal .....................................................................27
Disassembly...............................................................27
Inspection Ð Caliper .................................................27
Inspection Ð Rotor ....................................................28
Assembly ...................................................................28
Installation ..................................................................28
PARKING CENTER BRAKE CONTROL ......................29
Removal .....................................................................29
Inspection...................................................................29
Installation ..................................................................30
Adjustment .................................................................30
PARKING CENTER BRAKE .........................................31
Removal and Installation ...........................................31
Inspection Ð Drum ....................................................32
Inspection Ð Lining ...................................................32
ANTI-LOCK BRAKE SYSTEM ......................................33
Purpose......................................................................33
Operation ...................................................................33
ABS Hydraulic Circuit ................................................33
System Components .................................................34
System Description ....................................................34
Removal and Installation ...........................................36
TROUBLE DIAGNOSES ...............................................39
How to Perform Trouble Diagnoses for Quick
and Accurate Repair ..................................................39
Preliminary Check......................................................40
Component Parts and Harness Connector
Location .....................................................................41
Circuit Diagram for Quick Pinpoint Check.................42
Wiring Diagram Ð ABS Ð ........................................43
Self-diagnosis ............................................................47
CONSULT ..................................................................50
CONSULT Inspection Procedure...............................51
BR

Ground Circuit Check ................................................56
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC
ITEMS ........................................................................\
.....57
Diagnostic Procedure 1 (Wheel sensor or rotor) ......57
Diagnostic Procedure 2 (ABS actuator solenoid
valve and solenoid valve relay) .................................59
Diagnostic Procedure 3 (Motor relay or motor).........61
Diagnostic Procedure 4 (Low voltage) ......................63
Diagnostic Procedure 5 (G sensor) ...........................64
Diagnostic Procedure 6 (Control unit) .......................65
TROUBLE DIAGNOSES FOR SYMPTOMS .................66
Diagnostic Procedure 7 (ABS works frequently.) ......66
Diagnostic Procedure 8 (Unexpected pedal
action) ........................................................................\
67 Diagnostic Procedure 9 (Long stopping distance) ....67
Diagnostic Procedure 10 (ABS does not work.) .......68
Diagnostic Procedure 11 (Pedal vibration and
noise) ........................................................................\
.68
Diagnostic Procedure 12 (Warning lamp does
not come on when ignition switch is turned ON.) .....69
Diagnostic Procedure 13 (Warning lamp stays on
when ignition switch is turned ON.)...........................71
SERVICE DATA AND SPECIFICATIONS (SDS) ..........72
General Speci®cations ...............................................72
Inspection and Adjustment ........................................73
When you read wiring diagrams:
+ Read GI section, ``HOW TO READ WIRING DIAGRAMS''.
+ See EL section, ``POWER SUPPLY ROUTING'' for power distribution circuit.
When you perform trouble diagnoses, read GI section, ``HOW TO FOLLOW FLOW CHART
IN TROUBLE DIAGNOSES'' and ``HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN
ELECTRICAL INCIDENT''.

Bleeding Brake System
CAUTION:
+Carefully monitor brake ¯uid level at master cylinder dur-
ing bleeding operation.
+ If master cylinder is suspected to have air inside, bleed air
from master cylinder ®rst. Refer to ``Installation'', ``MAS-
TER CYLINDER'', BR-14.
+ Fill reservoir with new brake ¯uid ``DOT 3''. Make sure it is
full at all times while bleeding air out of system.
+ Place a container under master cylinder to avoid spillage
of brake ¯uid.
+ For models with ABS, turn ignition switch OFF and discon-
nect ABS actuator connectors or battery ground cable.
+ Bleed air in the following order.
1. LSV air bleeder
2. Left rear brake
3. Right rear brake
4. Left front brake
5. Right front brake
1. Connect a transparent vinyl tube to air bleeder valve.
2. Fully depress brake pedal several times.
3. With brake pedal depressed, open air bleeder valve to release air.
4. Close air bleeder valve.
5. Release brake pedal slowly.
6. Repeat steps 2. through 5. until clear brake ¯uid comes out of air bleeder valve.
7. Tighten air bleeder valve.
:7-9N zm (0.7 - 0.9 kg-m, 61 - 78 in-lb)
SBR995
SBR419C
CHECK AND ADJUSTMENT
BR-4

REMOVAL
CAUTION:
+Be careful not to splash brake ¯uid on painted areas; it
may cause paint damage. If brake ¯uid is splashed on
painted areas, wash it away with water immediately.
+ All hoses must be free from excessive bending, twisting
and pulling.
1. Connect vinyl tube to air bleeder valve.
2. Drain brake ¯uid from each air bleeder valve by depressing brake pedal.
3. Remove ¯are nut connecting brake tube and hose, then with- draw lock spring.
4. Cover openings to prevent entrance of dirt whenever discon- necting brake line.
INSPECTION
Check brake lines (tubes and hoses) for cracks, deterioration or
other damage. Replace any damaged parts.
INSTALLATION
CAUTION:
+Re®ll with new brake ¯uid ``DOT 3''.
+ Never reuse drained brake ¯uid.
1. Tighten all ¯are nuts and connecting bolts. Flare nut:
:15-17N zm (1.5 - 1.7 kg-m, 11 - 12 ft-lb)
Connecting bolt:
:17-19N zm (1.7 - 1.9 kg-m, 12 - 14 ft-lb)
2. Re®ll until new brake ¯uid comes out of each air bleeder valve.
3. Bleed air. Refer to ``Bleeding Brake System'', BR-4.
Load Sensing Valve
INSPECTION
CAUTION:
+ Carefully monitor brake ¯uid level at master cylinder.
+ Use new brake ¯uid ``DOT 3''.
+ Be careful not to splash brake ¯uid on painted areas; it
may cause paint damage. If brake ¯uid is splashed on paint
areas, wash it away with water immediately.
+ Depress pedal slowly when raising front brake pressure.
+ Check rear brake pressure 2 seconds after front brake
pressure reaches speci®ed value.
+ For models with ABS disconnect harness connectors from
ABS actuator relay before checking.
SBR992
SBR686C
BRAKE HYDRAULIC LINE/CONTROL VALVE
Brake Hydraulic Line (Cont'd)
BR-6

Disassembly
1. Bend claws of stopper cap outward.
2. Remove piston stopper while piston is pushed into cylinder(Models with ABS only).
3. Remove piston assemblies.
If it is difficult to remove secondary piston assembly, gradually
apply compressed air through ¯uid outlet.
4. Draw out reservoir tank.
Inspection
Check master cylinder inner wall for pin holes or scratches.
Replace if damaged.
Assembly
1. Insert secondary piston assembly. Then insert primary piston assembly.
+ Pay attention to direction of piston cups in ®gure at left.
Also, insert pistons squarely to avoid scratches on cylin-
der bore.
+ Pay attention to alignment of secondary piston slit with
valve stopper mounting hole of cylinder body (Models with
ABS only).
2. Install stopper cap.
Before installing stopper cap, ensure that claws are bent
inward.
3. Push reservoir tank seals into cylinder body.
4. Push reservoir tank into cylinder body.
SBR165E
SBR166E
SBR354C
SBR167E
MASTER CYLINDER
BR-13

5. Install valve stopper while piston is pushed into cylinder (Modelwith ABS only).
Installation
CAUTION:
+Re®ll with new brake ¯uid ``DOT 3''.
+ Never reuse drained brake ¯uid.
1. Place master cylinder onto brake booster and secure mounting nuts lightly.
2. Torque mounting nuts.
:12-15N zm (1.2 - 1.5 kg-m ,9-11ft-lb)
3. Fill up reservoir tank with new brake ¯uid.
4. Plug all ports on master cylinder with ®ngers to prevent air suction while releasing brake pedal.
5. Have driver depress brake pedal slowly several times until no air comes out of master cylinder.
6. Fit brake lines to master cylinder.
7. Tighten ¯are nuts.
:15-17N zm (1.5 - 1.7 kg-m, 11 - 12 ft-lb)
8. Bleed air. Refer to ``Bleeding Brake System'', BR-4.
SBR168E
SBR169E
MASTER CYLINDER
Assembly (Cont'd)
BR-14

Purpose
The Anti-Lock Brake System (ABS) consists of electronic and hydraulic components. It allows for control of
braking force so locking of the wheels can be avoided.
The ABS:
1) Improves proper tracking performance through steering wheel operation.
2) Eases obstacle avoidance through steering wheel operation.
3) Improves vehicle stability.
Operation
+When the vehicle speed is less than 10 km/h (6 MPH) this system does not work.
+ The Anti-Lock Brake System (ABS) has a self-test function. The system turns on the ABS warning lamp
for 1 second each time the ignition switch is turned ``ON''. After the engine is started, the ABS warning
lamp turns off. The system performs a test the ®rst time the vehicle reaches 6 km/h (4 MPH). A mechani-
cal noise may be heard as the ABS performs this self-test. This is a normal part of the self-test feature. If
a malfunction is found during this check, the ABS warning lamp will stay on.
+ While driving, a mechanical noise may be heard during ABS operation. This is a normal condition.
+ While DIFF-LOCK is on, the anti-lock brake warning light ¯ashes. This indicates that anti-lock may not be
fully operated. (ABS only)
ABS Hydraulic Circuit
j1Inlet solenoid valve
j
2Outlet solenoid valve
j
3Reservoir j
4Pump
j
5Motor
j
6Inlet valve j
7Outlet valve
j
8Bypass check valve
j
9Damper
SBR211E
ANTI-LOCK BRAKE SYSTEM
BR-33

System Components
System Description
WHEEL SENSOR
The sensor unit consists of a gear-shaped sensor rotor and a sen-
sor element. The element contains a bar magnet around which a
coil is wound. The sensor is installed on the back of the brake rotor.
As the wheel rotates, the sensor generates a sine-wave pattern.
The frequency and voltage increase(s) as the rotating speed
increases.
CONTROL UNIT (built in ABS actuator and electric unit)
The control unit computes the wheel rotating speed by the signal
current sent from the sensor. Then it supplies a DC current to the
actuator solenoid valve. It also controls ON-OFF operation of the
valve relay and motor relay. If any electrical malfunction should be
detected in the system, the control unit causes the warning lamp
to light up. In this condition, the ABS will be deactivated by the
control unit, and the vehicle's brake system reverts to normal
operation. (For control unit layout, refer to ABS ACTUATOR AND
ELECTRIC UNIT, BR-34.)
SBR185E
SBR186E
ANTI-LOCK BRAKE SYSTEM
BR-34

G SENSOR
The G sensor senses deceleration during braking to determine whether the vehicle is being driven on a high
 road (asphalt road, etc.) or a low  road (snow-covered road, etc.). It then sends a signal to the ABS con-
trol unit.
The reed switch turns on when it is affected by a magnetic ®eld. During sudden deceleration (braking on a
high  road), the weight moves and the magnet in the weight moves away from the reed switch. The mag-
netic ®eld then diminishes and the reed switch turns off.
ABS ACTUATOR AND ELECTRIC UNIT
The ABS actuator and electric unit contains:
+An electric motor and pump
+ Two relays
+ Six solenoid valves, each inlet and outlet for
Ð LH front
Ð RH front
Ð Rear
+ ABS control unit
This component controls the hydraulic circuit and increases, holds
or decreases hydraulic pressure to all or individual wheels. The
ABS actuator and electric unit are not disassemble.
ABS actuator operation
Inlet solenoid
valve Outlet solenoid
valve
Normal brake operation OFF (Open) OFF (Closed) Master cylinder brake ¯uid pressure is directly trans-
mitted to wheel cylinder via the inlet solenoid valve.
ABS operation Pressure hold ON (Closed) OFF (Closed)
Hydraulic circuit is shut off to hold the wheel cylinder
brake ¯uid pressure.
Pressure
decrease ON (Closed) ON (Open) Wheel cylinder brake ¯uid is sent to reservoir via the
outlet solenoid valve. Then it is pushed up to the
master cylinder by pump.
Pressure
increase OFF (Open) OFF (Closed) Master cylinder brake ¯uid pressure is transmitted to
wheel cylinder.
SBR189E
SBR176E
ANTI-LOCK BRAKE SYSTEM
System Description (Cont'd)
BR-35

Removal and Installation
CAUTION:
Be careful not to damage sensor edge and sensor rotor teeth.
When removing the front wheel hub or rear axle shaft
assembly, disconnect the ABS wheel sensor from the assem-
bly and move it away.
FRONT WHEEL SENSOR
SBR187E
ANTI-LOCK BRAKE SYSTEM
BR-36