ect LEXUS SC300 1991 Service Repair Manual

PARKING BRAKE COMPONENTS
INSPECTION AND REPAIR
BR04G±0B
1. INSPECT DISASSEMBLED PARTSInspect the disassembled parts for wear, rust or damage.
2. MEASURE BRAKE SHOE LINING THICKNESS Using a scale, measure the thickness of the shoe lining.
Standard thickness:
2.5 mm (0.098 in.)
Minimum thickness: 1.0 mm (0.039 in.)
If the lining thickness is at the minimum thickness or less, or
if there is extremely uneven wear, replace the brake shoe.
3. MEASURE BRAKE DISC INSIDE DIAMETER Using a vernier caliper, measure the inside diameter of the
disc.
Standard inside diameter:
190 mm (7.48 in.)
Maximum inside diameter: 191 mm (7.52 in.)
Replace the disc if the inside di ameter is at the maximum val-
ue or more. Replace the disc or grind it with a lathe if the disc
is scored or is worn unevenly.
4. INSPECT P ARKING BRAKE LINING AND DISC FOR
PROPER CONTACT
Apply chalk to the inside surface of the disc, then grind down
the brake shoe lining to fit. If the contact between the disc and
the brake shoe lining is improper, repair it using a brake shoe
grinder or replace the brake shoe assembly.
5. MEASURE CLEARANCE BETWEEN PARKING BRAKE SHOE AND LEVER
Using a feeler gauge, measure the clearance.
Standard clearance:
Less than 0.35 mm (0.0138 in.)
If the clearance is not within the specification, replace the
shim with one of the correct size.
BR±46
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)
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Thickness mm(in.) Thickness mm(in.)
 0.3 (0.012) 0.9 (0.035)
 

0.6 

(0.024) 


 


6. IF NECESSARY, REPLACE SHIM
(a) Remove the parking brake shoe lever, and install the correct
size shim.
(b) Install the parking brake shoe lever with a new Cwasher.
(c) Remeasure the clearance.
PARKING BRAKE ASSEMBLY
BR0ES±04
HINT: Assemble the parts in the correct direction, as shown.
1. APPLY HIGH TEMPERATURE GREASE ON BACK± ING PLATE
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)BR±47
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2. APPLY HIGH TEMPERATURE GREASE TO ADJUSTER
3. CONNECT PARKING BRAKE CABLE TO PARKINGBRAKE LEVER
(a) Install the shoe hold±down springs, cups and pins.
(b) Connect the parking brake cable to the parking brake shoe
lever of the rear shoe.
4. INSTALL REAR SHOE Slide in the rear shoe between the shoe hold±down spring
cup and the backing plate.
NOTICE: Do not allow oil or grease to get on the rubbing face.
5. INSTALL TENSION SPRING, FRONT SHOE ANDADJUSTER
(a) Install the tension spring on the rear shoe.
(b) Install the front shoe on the tension spring.
(c) Install the adjuster between the front and rear shoes.
(d) Slide in the front shoe between the shoe hold±down spring
cup and the backing plate.
BR±48
±
BRAKE SYSTEM REAR BRAKE (Parking Brake)
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PROPORTIONING AND BY±PASS
VALVE (P & B VALVE)
FLUID PRESSURE INSPECTION
BR0ET±01
1. INSTALL LSPV GAUGE (SST) AND BLEED AIRSST 09709±29017
2. RAISE MASTER CYLINDER PRESSURE AND CHECKREAR WHEEL CYLINDER PRESSURE
 Master cylinder pressure Rear wheel cylinder pressure
 1,961 kPa 1,961 kPa 

(20 kgf/cm2, 284 psi) 

(20 kgf/cm2, 284 psi)
 7,845 kPa5,492 kPa
 (80 kgf/cm2, 1,138 psi) (56 kgf/cm2, 796 psi)
Specifications: If the rear wheel cylinder pressure is in-
correct, replace the master cylinder.
3. BLEED BRAKE SYSTEM
4. CHECK FOR FLUID LEAKAGE
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BRAKE SYSTEM PROPORTIONING AND BY±PASS VALVE (P & B
VALVE)BR±51
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ANTI±LOCK BRAKE SYSTEM (ABS)
BR0EU±04
DESCRIPTION

ABS is a brake system which controls the brake cylinder hydraulic pressure \
to all 4 wheels during sudden
braking and braking on slippery road surfaces, preventing the wheels from locki\
ng. ABS provides the
following benefits:
(1) Enables steering round an obstacle with a greater degree of certai\
nty even when panic braking.
(2) Enables stopping during panic braking while keeping the effect upon stability and steerability to a mini-
mum, even on curves.

In case a malfunction occurs, a diagnosis function and fail±safe system have been adopted for the ABS.
SYSTEM PARTS LOCATION
BR02L±05
BR±52±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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MAIN POINT OF REMOVAL AND
INSTALLATION
1. w/ TRAC:DRAIN OUT HIGH PRESSURE FLUID
(a) Connect a vinyl t ube to the TRAC actuator bleeder plug, then
loosen the bleeder plug.
(b) When the fluid has flowed out, tighten the bleeder plug. CAUTION: Since the fluid is under high pressure, it could
stray out with great force, so be careful.
2. DISCONNECT AND CONNECT BRAKE LINE w/ TRAC:
Using SST, disconnect and connect the brake lines from/to
the ABS actuator and TRAC actuator.
SST 09023±00100
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
w/o TRAC:
Using SST, disconnect and connect the brake lines from/to
the ABS actuator.
SST 09023±00100
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
3. w/ TRAC:
REMOVE AND INSTALL TRAC ACTUATOR
Loosen and tighten the 3 bolts.
Torque: 15 N Vm (155 kgf Vcm, 11 ft Vlbf)
HINT: When loosening or tightening TRAC actuator installa-
tion bolts, lift the actuator bracket up slightly from the body.
4. BLEED BRAKE SYSTEM
(See page BR±8)
5. w/ TRAC: BLEED TRAC SYSTEM
(See page BR±10)
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±63
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ABS ACTUATOR INSPECTION
BR0F1±03
HINT: Using the ABS actuator checker (SST), check the op-
eration of the actuator. If the actuator does not operate,
check the operation of sub±wire harness G according to
instructions on pages BR±97 and BR101. If the solenoid and/
or pump motor relay are abnormal, replace the relay and in-
spect the actuator operation again.
w/o TRAC:
1. INSPECT BATTERY POSITIVE VOLTAGE
Battery positive voltage:
10±14V
2. DISCONNECT CONNECTORS FROM ACTUATORDisconnect the 2 connectors from the actuator.
3. CONNECT ACTUATOR CHECKER (SST) TO ACTUATOR
(a) Connect the actuator checker (SST) to the actuator side wire harnesses via the sub±wire harnesses (SST), as shown.
SST 09990±00150, 09990±00210, 09990±00250 and09990±00280
(b) Connect the red cable of the checker to the battery positive (+) terminal and the black cable to negative (±) terminal.
Connect the black cable of the sub±wire harnesses to the
battery negative (±) terminal or body ground.
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±65
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4. INSPECT BRAKE ACTUATOR OPERATION
(a) Start the engine, and run it at idle speed.
(b) Turn the MAIN selector switch of the actuator checker to theªFRONT RHº position.
(c) Push and hold in the SUB MOTOR switch for a few seconds.
(d) Depress the brake pedal and hold it until step (g) is completed.
(e) Push the MAIN push switch and check that the brake pedal can not be depressed.
NOTICE: Do not keep the MAIN push switch pushing more
than 10 seconds.
(f) Re le a se th e switch , an d ch e ck th a t th e p edal can be
depressed.
(g) Push and hold in the SUB MOTOR switch for a few seconds, and check that the pedal returns.
(h) Release the brake pedal.
(i) Push and hold in the SUB MOTOR switch for a few seconds.
(j) Depress the brake pedal and hold it for about 15 seconds. As
you hold the pedal down, push the SUB MOTOR switch for
a few seconds. Check that the brake pedal does not pulsate.
5. INSPECT FOR OTHER WHEELS
(a) Turn the MAIN selector switch to the ªFRONT LHº position.
(b) Repeat (c) to (j) of step 4, checking the actuator operation in the same way.
(c) Also, inspect the ªREARº positions following the same procedure.
BR±66
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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6. PUSH SUB MOTOR SWITCHPush and hold in the SUB MOTOR switch for a few seconds.
7. DISCONNECT ACTUATOR CHECKER (SST) FROM ACTUATOR
(a) Disconnect the actuator checker (SST) and sub±wire
harnesses (SST) from the actuator.
SST 09990±00150, 09990±00210, 09990±00250 and09990±00280
(b) Connect the actuator connectors.
(c) Clear the diagnostic trouble codes.
(See page BR±77)
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)BR±67
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w/ TRAC:
1. INSPECT BATTERY POSITIVE VOLTAGE
Battery positive voltage:10±14 V
2. DISCONNECT CONNECTORS FROM ACTUATORDisconnect the 2 connectors from the actuator.
3. CONNECT ACTUATOR CHECKER (SST) TO ACTUATOR
(a) Connect the actuator checker (SST) to the actuator side wire harnesses via the sub±wire harnesses (SST), as shown.
SST 09990±00150 and 09990±00250
(b) Connect the red cable of the checker to the battery positive (+) terminal and the black cable to negative (±) terminal.
Connect the black cable of the sub±wire harnesses to the
battery negative (±) terminal or body ground.
(c) Place ªSHEET Aº (SST) on the actuator checker. SST 09990±00163
4. INSPECT BRAKE ACTUATOR OPERATION
(a) Start the engine, and run it at idle speed.
(b) Turn the selector switch of the actuator checker to the ªFRONT RHº position.
(c) Push and hold in the MOTOR switch for a few seconds.
(d) De p re ss th e bra ke p edal and hold it until step (g) is
completed.
BR±68
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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