LEXUS LS430 2003 Factory Repair Manual

Fig. 54: Exploded View Of Brake Booster Assy
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ON-VEHICLE INSPECTION
1.OPERATION CHECK
a. Depress the brake pedal several times with the en
gine 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.
If not, replace the brake booster.
Fig. 55: Identifying Brake Pedal Operation Check

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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 can be depressed to the floor the first time, but on the 2nd or 3rd time cannot be
depressed as far, the booster is airtight.
If not, replace the brake booster.
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 the pedal is held for 30 seconds, the booster is
air tight.
If not, replace the brake booster.

Fig. 56: Identifying Air Tightness Check
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3.INSPECT VACUUM CHECK VALVE
a. Check that there is ventilation from the booster to engine, and no ventilation from the engine to the
booster.
b.If any fault is found, replace the vacuum check valve.

Fig. 57: Inspecting Vacuum Check Valve
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REPLACEMENT
1.REMOVE ENGINE ROOM SIDE COVER
2.SEPARATE ENGINE ROOM NO.3 R/B
a. Remove the bolt and separate the engine room No.3 R/B.
3.DRAIN BRAKE FLUID
a. Draw out fluid with syringe.
4.REMOVE BRAKE MASTER CYLINDER SUB-ASSY
a. Remove the clamp from the 2 brake tubes.

Fig. 58: Removing Clamp From Brake Tubes
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b. Using SST, remove the 2 brake tubes from the master cylinder and ABS & TRACTION actuator
assy.
SST 09751-36011

Fig. 59: Removing Brake Tubes From Master Cylinder And ABS & TRACTION Actuator
Assy
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c. Disconnect the brake fluid level warning switch connector from the brake master cylinder reservoir.
d. Remove the 2 nuts, vacuum check valve bracket and brake master c
ylinder sub-assy.

Fig. 60: Removing Brake Master Cylinder Sub-Assy Nuts
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5.REMOVE INSTRUMENT CLUSTER FINISH PANEL END
6.REMOVE INSTRUMENT CLUSTER FINISH PANEL CENTER LOWER
7.REMOVE INSTRUMENT PANEL UNDER COVER SUB-ASSY NO.1 (SEE REPLACEMENT
)
8.REMOVE COIN BOX ASSY
9.REMOVE OUTER MIRROR SWITCH ASSY
10.REMOVE INSTRUMENT PANEL SAFETY PAD SUB-ASSY NO.1 (SEE REPLACEMENT
)
11.REMOVE INSTRUMENT PANEL UNDER COVER SUB-ASSY NO.2
a. Remove the 2 bolts and hood lock release lever.
b. Remove the instrument panel under cover sub-assy No.2.
12.REMOVE BRAKE PEDAL RETURN SPRING
a. Remove the brake pedal return spring.
13.REMOVE BRAKE MASTER CYLINDER PUSH ROD CLEVIS
a. Remove the clip and the push rod pin.
b. Loosen the clevis lock nut and remove the brake master cylinder push rod clevis.
c. Remove the clevis lock nut.

Fig. 61: Removing Clip And Push Rod Pin
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14.REMOVE BRAKE BOOSTER ASSY
a. Slide the clip upward and disconnect the vacuum hose ass
y from the vacuum check valve assy.

Fig. 62: Disconnecting Vacuum Hose Assy From Vacuum Check Valve Assy
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b. Remove the 4 nuts and pull out the brake booster assy.
c. Remove the brake booster
gasket.

Fig. 63: Removing Nuts And Brake Booster Assy
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15.REMOVE BRAKE VACUUM CHECK VALVE ASSY
a. Remove the vacuum check valve assy and the grommet from the brake booster assy.
16.INSTALL BRAKE VACUUM CHECK VALVE ASSY
a. Install the
grommet and the vacuum check valve assy to the brake booster assy.