LEXUS SC400 1991 Service Repair Manual

COMPONENTS
BR03T±05
MASTER CYLINDER DISASSEMBLY
BR0EG±05
1. REMOVE MASTER CYLINDER BOOTUsing a screwdriver, remove the master cylinder boot.
2. REMOVE RESERVOIR CAP AND STRAINER
(a) Turn the reservoir cap the ªopenº side and remove it.
(b) Remove the strainer.
BR±14
±
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.
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BRAKE SYSTEM MASTER CYLINDERBR±15
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MASTER CYLINDER ASSEMBLY
BR0EH±05
1. APPLY LITHIUM SOAP BASE GLYCOL GREASE TORUBBER PARTS INDICATED BY ARROWS
2. INSTALL PISTONS
NOTICE: Be careful not to damage the rubber lips on the pis-
tons.
(a) Insert the 2 pistons straight in, not at an angle.
NOTICE: If inserted at an angle, there is a possibility that the
cylinder bore could be damaged.
(b) Push in the piston with a screwdriver and install the snap ring
with snap ring pliers.
HINT: Tape the screwdriver tip before use.
3. w/ TRAC: INSTALL NO. 1 PISTON STOPPER BOLT
Using a screwdriver, push the piston in all the way and install
the No. 1 piston stopper bolt over a new gasket.
Torque: 10 N Vm (100 kgf Vcm, 7 ft Vlbf)
4. INSTALL NO. 2 PISTON STOPPER BOLT
Using a screwdriver, push the piston in all the way and install
the No. 2 piston stopper bolt over a new gasket.
Torque: 10 N Vm (100 kgf Vcm, 7 ft Vlbf)
5. INSTALL 2 GROMMETS
6. INSTALL RESERVOIR
(a) Install the strainer to the reservoir.
(b) Push the reservoir onto the cylinder.
(c) Install the set screw while pushing on the reservoir.
Torque: 1.7 N Vm (17.5 kgf Vcm, 15.2 in. Vlbf)
7. 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.
BR±16
±
BRAKE SYSTEM MASTER CYLINDER
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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
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BRAKE SYSTEM BRAKE BOOSTER
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3. REMOVE BRAKE BOOSTER
(a) Remove the booster installation nuts.
(b) Remove the booster and gasket.
BRAKE BOOSTER INSTALLATION
BR03Z±08
1. INSTALL BRAKE BOOSTER
(a) Install the booster and gasket.
(b) Install and torque the booster installation nuts.
Torque: 12 NVm (125 kgf Vcm, 9 ft Vlbf)
(c) Insert the clevis pin into the clevis and brake pedal, and install
the clip to the clevis pin.
(d) Install the pedal return spring.
2. ADJUST LENGTH OF BOOSTER PUSH ROD
(a) Install the gasket on the master cylinder.
(b) Set the SST on the gasket, and lower the pin until its tip slightly touches the piston.
SST 09737±00010
(c) Turn the SST upside down, and set it on the booster. SST 09737±00010
(d) Measure the clearance between the booster push rod and
pin head (SST).
Clearance:
0 mm (0 in.)
(e) Adjust the booster push rod length until the push rod lightlytouches the pin head.
HINT: When adjusting the push rod, depress the brake pedal
enough so that the push rod sticks out.
3. INSTALL FOLLOWING PARTS: wVacuum hose
w Master cylinder
(See page BR±12)
w w/ TRAC:
TRAC pump assembly
(See page BR±162)
±
BRAKE SYSTEM BRAKE BOOSTERBR±19
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4. FILL BRAKE RESERVOIR WITH BRAKE FLUID AND
BLEED BRAKE SYSTEM
(See page BR±8)
5. w/ TRAC:
BLEED TRAC SYSTEM
(See page BR±10)
6. CHECK FOR FLUID LEAKAGE
7. CHECK AND ADJUST BRAKE PEDAL (See page BR±7)
8. PERFORM OPERATIONAL CHECK (See page BR±8)
BR±20
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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.)
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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
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BRAKE SYSTEM FRONT BRAKE (SC400)
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(c) Install the new pad support plates.
8. INSTALL NEW PADS
(a) Apply disc brake grease to both sides of the inner anti±squeal
shim.
(b) Install the 2 anti±squeal shims on each pad.
(c) Install inner pad with the pad wear indicator plates facing downward.
(d) Install the outer pad.
NOTICE: There should be no oil or grease adhering to the fric-
tion surfaces of the pads or the disc.
(e) Install the 2 anti±squeal springs.
9. INSTALL CALIPER
(a) Draw out a small amount of brake fluid from the reservoir.
(b) P re ss in th e pisto n with wa te r pu mp plie rs or simila r
implement.
HINT: If the piston is difficult to push in, loosen the bleeder
plug and push in the piston while letting some brake fluid es-
cape.
(c) Install the caliper.
(d) Hold the sliding pin and torque the installation bolt.
Torque: 34 N Vm (350 kgf Vcm, 25 ft Vlbf)
10. INSTALL FRONT WHEEL
11. CHECK THAT FLUID LEVEL IS AT MAX LINE
CALIPER REMOVAL
BR042±0C
1. DISCONNECT FLEXIBLE HOSE
(a) Remove the union bolt and 2 gaskets from the caliper, then
disconnect the flexible hose from the caliper.
(b) Use a container to catch the brake fluid as it drains out.
±
BRAKE SYSTEM FRONT BRAKE (SC400)BR±31
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