ect LEXUS SC300 1991 Service Repair Manual

4. CHECK THAT PEDAL RESERVE DISTANCE IS CORRECT,
AS SHOWN
Release the parking brake.
With the engine running, depress the pedal and measure the
pedal reserve distance, as shown.
Pedal reserve distance at 490 N (50 kgf, 110.2 lbf):
More than 89 mm (3.50 in.)
If the reserve distance is incorrect, troubleshoot the brake
system.
BRAKE BOOSTER OPERATIONAL TEST
BR03P±0B
1. OPERATING CHECK
(a) Depress the bake pedal several times with the engine off and
check that there is no change in the pedal reserve distance.
(b) Depress the brake pedal and start the engine. If the pedal goes down slightly, operation is normal.
2. AIR TIGHTNESS CHECK
(a) Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly. If the pedal goes down the
farthest the 1st time, but gradually rises after the 2nd or 3rd
time, the booster is air tight.
(b) Depress the brake pedal while the engine is running, and stop the engine with the pedal depressed. If there is no
change in the pedal reserve travel after holding the pedal for
30 seconds, the booster is air tight.
BRAKE SYSTEM BLEEDING
BR0ED±04
HINT: If any work is done on the brake system or if air in the
brake lines is suspected, bleed the system of air.
NOTICE: Do not let brake fluid remain on painted sur-
faces. Wash it off immediately.
1. REMOVE RESERVOIR CAP Turn the reservoir cap to the ªopenº side and remove it.
2. FILL RESERVOIR WITH BRAKE FLUID
Fluid: SAE J1703 or FMVSS NO.116DOT3
BR±8±
BRAKE SYSTEM CHECK AND ADJUSTMENT
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3. BLEED MASTER CYLINDERHINT: If the master cylinder has been disassembled or if the
reservoir becomes empty, bleed the air from the master cylin-
der.
(a) Disconnect the brake lines from the master cylinder.
(b) Slowly depress the brake pedal and hold it.
(c) Block off the outer holes with your fingers, and release the brake pedal.
(d) Repeat (b) and (c) 3 or 4 times.
4. BLEED BRAKE LINE
(a) Connect the vinyl tube to the brake caliper.
(b) Depress the brake pedal several times, then loosen the
bleeder plug with the pedal held down.
(c) At the point when fluid stops coming out, tighten the bleeder plug, then release the brake pedal.
(d) Repeat (b) and (c) until all the air in the fluid has been bled
out.
(e) Repeat the above procedure to bleed the air out of the brake
line for each wheel.
Torque: 11 N Vm (110 kgf Vcm, 8 ft Vlbf)
5. CHECK FLUID LEVEL IN RESERVOIR
Check the fluid level and add fluid if necessary.
Fluid:
SAE J1703 or FMVSS NO.116DOT3
6. INSTALL RESERVOIR CAP
(a) Align the matchmark on the reservoir cap with the matchmark
on the ªopenº side of reservoir.
(b) Push down on the reservoir cap and turn it clockwise until it locks.
(c) Check that the matchmark on the reservoir cap is now aligned with the matchmark on the ªcloseº side of the
reservoir.
±
BRAKE SYSTEM CHECK AND ADJUSTMENTBR±9
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TRAC CONTROL SYSTEM BLEEDING
BR0EE±03
1. BLEED TRACTION CONTROL SYSTEMCAUTION:
w The fluid is under high pressure, and could spray out with
great force, so exercise caution.
w When repairing the brake master cylinder or TRAC
system, bleed the air out of the TRAC system.
(a) Connect a vinyl tube to the bleeder plug of accumulator, then
loosen the bleeder plug.
(b) Start the engine to allow the TRAC pump motor to operate
until all the air has been bled out of the fluid.
(c) Tighten the bleeder plug and stop the engine.
Torque: 8.3 N Vm (85 kgf Vcm, 74 in. Vlbf)
(d) C onnect a vinyl tube to the bleeder plug of the TRAC
actuator, then loosen the bleeder plug.
(e) Start the engine to allow the TRAC pump motor to operate
until all the air has been bled out of the fluid.
(f) Tighten the bleeder plug and stop the engine. Torque: 8.3 N Vm (85 kgf Vcm, 74 in. Vlbf)
(g) Check if any diagnostic trouble code is output which indicates
trouble. If there is, clear the diagnostic trouble code.
2. CHECK FLUID LEVEL IN RESERVOIR Check the fluid level and add fluid if necessary.
Fluid:
SAE J1703 or FMVSS NO. 116DOT3
HINT: Add fluid with the engine idling.
BR±10
±
BRAKE SYSTEM CHECK AND ADJUSTMENT
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PARKING BRAKE CHECK AND
ADJUSTMENT
BR03R±04
1. CHECK THAT PARKING BRAKE LEVER TRAVEL IS
CORRECT
Pull the parking brake lever all the way up, and count the
number of clicks.
Parking brake lever travel at 196 N (20 kgf, 44.1 lbf):
5±8 clicks
If incorrect, adjust the parking brake.
2. IF NECESSARY, ADJUST PARKING BRAKE HINT: Before adjusting the parking brake, make sure that the
rear brake shoe clearance has been adjusted.
For shoe clearance adjustment, see page BR±49.
(a) Remove the cup holder.
(b) Using a socket driver and spanner wrench, remove the adjusting lock nut.
HINT: Tape the socket driver before use.
(c) Turn the adjusting nut until the lever travel is correct.
(d) Install the adjusting lock nut.
(e) Using a socket driver and s panner wrench, tighten the
adjusting lock nut.
Torque: 5.4 N Vm (55 kgf Vcm, 48 in. Vlbf)
(f) Install the cup holder.
±
BRAKE SYSTEM CHECK AND ADJUSTMENTBR±11
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MASTER CYLINDER
MASTER CYLINDER REMOVAL
BR0EF±03
1. w/ TRAC:DRAIN OUT HIGH PRESSURE FLUID
(a) C onnect a vinyl tube to the bleeder plug of the TRAC
actuator, then loosen the bleeder plug with the ignition switch
in the OFF position.
CAUTION: The fluid is under high pressure, and could spray
out with great force, so exercise caution.
(b) Tighten the plug when fluid stops flowing out.
2. DISCONNECT LEVEL WARNING SWITCH CONNECTOR
3. DRAW OUT FLUID WITH SYRINGE
NOTICE: Do not let brake fluid remain on a painted surface.
Wash it off immediately.
4. DISCONNECT BRAKE LINES Using SST, disconnect the brake lines from the master cylin-
der.
SST 09023±00100
BR±12
±
BRAKE SYSTEM MASTER CYLINDER
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3. REMOVE RESERVOIRRemove the set screw and pull out the reservoir.
4. REMOVE 2 GROMMETS
5. PLACE CYLINDER IN VISE
6. w/ TRAC: REMOVE NO.1 PISTON STOPPER BOLT
Using a screwdriver, push the pistons in all the way and re-
move the No.1 piston stopper bolt and gasket.
HINT: Tape the screwdriver tip before use.
7. REMOVE NO.2 PISTON STOPPER BOLT Using a screwdriver, push the pistons in all the way and re-
move the No.2 piston stopper bolt and gasket.
8. REMOVE PISTONS
(a) Push in the piston with a screwdriver and remove the snap ring with snap ring pliers.
(b) Remove the No. 1 piston and spring by hand, pulling straight out, not at an angle.
NOTICE: If pulled out at an angle, there is a possibility that the
cylinder bore could be damaged.
(c) Place a rag and 2 wooden blocks on the work table and lightly
tap the cylinder flange against the block edges until the piston
drops out of the cylinder.
HINT: Make sure the distance (A) from the rag to the top of
the blocks is at least 100 mm (3.94 in.).
MASTER CYLINDER COMPONENTS
INSPECTION
BR03V±05
HINT: Clean the disassembled parts with compressed air.
1. INSPECT CYLINDER BORE FOR RUST OR SCORING
2. INSPECT CYLINDER FOR WEAR OR DAMAGE If necessary, clean or replace the cylinder.
±
BRAKE SYSTEM MASTER CYLINDERBR±15
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8. INSTALL MASTER CYLINDER BOOTWith the UP mark on the master cylinder boot facing up-
wards, install the cylinder boot on the master cylinder.
MASTER CYLINDER INSTALLATION
BR0EJ±05
1. ADJUST LENGTH OF BRAKE BOOSTER PUSH RODBEFORE INSTALLING MASTER CYLINDER
(See page
BR±19)
2. INSTALL MASTER CYLINDER Install the master cylinder and a new gasket on the brake
booster with 3 nuts.
Torque: 13 N Vm (130 kgf Vcm, 9 ft Vlbf)
3. CONNECT BRAKE LINES
Using SST, connect the brake lines to the master cylinder.
Torque the union nuts.
SST 09023±00100
Torque: 12 N Vm (125 kgf Vcm, 9 ft Vlbf)
4. CONNECT LEVEL WARNING SWITCH CONNECTOR
5. FILL BRAKE R ESERVOIR WITH BRAKE FLUID AND
BLEED BRAKE SYSTEM
(See page BR±8)
6. w/ TRAC:
BLEED TRAC SYSTEM
(See page BR±10)
7. CHECK FOR FLUID LEAKAGE
8. CHECK AND ADJUST BRAKE PEDAL (See page BR±7 )
±
BRAKE SYSTEM MASTER CYLINDERBR±17
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BRAKE BOOSTER
BRAKE BOOSTER REMOVAL
BR0EK±03
1. w/ TRAC:DRAIN OUT HIGH PRESSURE FLUID
(a) C onnect a vinyl tube to the bleeder plug of the TRAC
actuator, then loosen the bleeder plug with the ignition switch
in the OFF position.
CAUTION: The fluid is under high pressure, and could
spray out with great force, so exercise caution.
(b) Tighten the plug when fluid stops flowing out.
2. REMOVE FOLLOWING PARTS: wMaster cylinder
(See page BR±12)
w w/ TRAC:
TRAC pump assembly
(See page BR±162)
w Vacuum hose
w Clip and return spring
BR±18
±
BRAKE SYSTEM BRAKE BOOSTER
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FRONT BRAKE (SC400)
COMPONENTS
BR040±0A
BRAKE PADS REPLACEMENT
BR0PU±01
1. REMOVE FRONT WHEELRemove the wheel and temporarily fasten the disc with the
hub nuts.
2. INSPECT PAD LINING THICKNESS Check the pad thickness through the caliper inspection hole
and replace the pads if it is not within the specification.
Minimum thickness:
1.0 mm (0.039 in.)
±
BRAKE SYSTEM FRONT BRAKE (SC400)BR±29
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3. LIFT UP CALIPER
(a) Hold the sliding pin on the bottom and loosen the installationbolt.
(b) Remove the installation bolt.
(c) Lift up and suspend the caliper.
HINT: Do not disconnect the flexible hose from the caliper.
4. REMOVE FOLLOWING PARTS:
(a) 2 anti±squeal springs
(b) 2 brake pads
(c) 4 anti±squeal shims
(d) 4 pad support plates
5. CHECK DISC THICKNESS AND RUNOUT (See page BR±33 )
6. INSTALL UNDER SIDE PAD SUPPORT PLATES
7. INSTALL UPPER SIDE PAD SUPPORT PLATES
(a) Using cleaner, wipe off dust, water, oil, etc. from the pad support plate contact area of the torque plate.
(b) Remove the pad support cover sheets from new pad support plate.
BR±30
±
BRAKE SYSTEM FRONT BRAKE (SC400)
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