Disc Brakes: Other Lexus LS III

BLEEDING BRAKE SYSTEM

Note. Use only SAE J1703 or FMVSS No. 116 DOT 3 brake fluid.

BLEEDING PROCEDURES

Brake System

1. ABS bleeding procedure is the same for all systems. On models without TRAC, if master cylinder reservoir is empty or is suspected of containing air, bleed master cylinder first. On models with TRAC, bleed TRAC system first. See «TRACTION CONTROL SYSTEM (ES300, IS300 & RX300)»(ref-127897-S29241812242001103000000) , «TRACTION CONTROL SYSTEM (GS300 & GS430)»(ref-127897-S20411818722001103000000) or «TRACTION CONTROL SYSTEM (LS430)»(ref-127897-S36741734652001103000000) .
2. Ensure master cylinder reservoir is full. Connect vinyl tube to caliper bleeder plug, and insert other end of tube in a clear container 1/2 full of brake fluid.
3. Slowly depress brake pedal several times. While depressing brake pedal, loosen bleeder plug until fluid starts to flow. Close bleeder screw. Repeat operation until bubbles are not present in fluid. Tighten bleeder screw to 74 INCH lbs. (8.3 N.m). See «BRAKELINE BLEEDING SEQUENCE»(ref-127897-S02200658572001103000000) .

Note. If master cylinder has been disassembled, is new or if reservoir has run dry, bleed master cylinder before bleeding wheels.

BRAKELINE BLEEDING SEQUENCE

Traction Control System (ES300, IS300 & RX300)

Remove reservoir cap. Install hand pump with gauge and hose to reservoir and apply 14.2 psi. (1 kgf.cm 2 ). See upper portion of (Scheme 13). Connect vinyl tube to bleeder plug of brake actuator and loosen bleeder plug. See lower portion of (Scheme 13). Bleed air from actuator and tighten bleeder plug to 74 INCH lbs. (8.3 N.m ). Add brake fluid if necessary.

Scheme 13

Scheme 14

1. Disconnect 2 connectors from hydraulic brake booster. Connect Actuator Tester (09990-00150) to hydraulic brake booster side wire harness via Sub-Wire Harness (09990-00480). (Scheme 14)
2. Connect Red cable of tester to battery positive terminal and Black cable to negative terminal. Turn ignition switch to OFF position, and depress brake pedal more than 40 times. Turn ignition to ON, ensure pump stops after 30-40 seconds. If pump does not stop, repeat step.
3. Depress brake pedal more than 20 times with ignition on, and bleed right and left front calipers. Hold and depress brake pedal. Bleed right and left rear wheel caliper.
4. Bleed right front brake line. Turn selector switch of actuator tester to FRONT RH position. Push and hold in MAIN push switch. Depress brake pedal and hold to bleed right front brake caliper. Repeat until there are no air bubbles in fluid.
5. Bleed left front brake line. Turn selector switch of actuator tester to FRONT LH position. Push and hold in MAIN push switch. Depress brake pedal and hold to bleed left front brake caliper. Repeat until there are no air bubbles in fluid.
6. Bleed rear brake line. Push and hold in SUB LH and SUB RH switches. Bleed right and left rear brake caliper. Repeat until there are no air bubbles in fluid.
7. Disconnect actuator connector and sub-wire harness from actuator. Connect 2 connectors to hydraulic brake booster. Clear DTC.

Traction Control System (LS430)

1. Ensure master cylinder reservoir is full of brake fluid. Slowly depress brake pedal and hold it. Block off outlet plugs with your fingers, and release brake pedal. Repeat 3 or 4 times.
2. Turn ignition off. Connect vinyl tube to bleeder screw of TRAC actuator. Loosen bleeder screw. Start engine and allow TRAC pump to operate until all air has been bled from actuator side. Tighten bleeder screw to 74 INCH lbs. (8.4 N.m) and turn engine off.

BRAKE PEDAL HEIGHT & FREE PLAY

1. Measure pedal height from floor board to face of pedal pad. See «BRAKE PEDAL HEIGHT & FREE PLAY SPECIFICATIONS»(ref-127897-S28171579972001103000000) . If pedal height is incorrect, go to next step.
2. On ES300, IS300, LS430 and RX300, remove undercover panel, lower pad and air duct. On all models, disconnect stoplight switch connector. Loosen stoplight switch lock nut, and remove stoplight switch. Loosen brake pedal-to-power brake unit push rod lock nut.
3. Adjust pedal height by turning brake pedal push rod. Tighten push rod lock nut to 19 ft. lbs. (25 N.m). Install brake light switch. On ES300, IS300, LS430 and RX300, install undercover panel, lower pad and air duct.
4. STOP engine and depress brake pedal several times until power brake unit is depleted. Push brake pedal by hand until a second point of resistance is felt, then measure pedal free play. Ensure pedal free play is as specified. See «BRAKE PEDAL HEIGHT & FREE PLAY SPECIFICATIONS»(ref-127897-S28171579972001103000000) .

BRAKE PEDAL HEIGHT & FREE PLAY SPECIFICATIONS

POWER BRAKE UNIT PUSH ROD

1. Adjust power brake unit push rod length before installing new master cylinder or power brake unit. Install master cylinder gasket. Place Master/Booster Push Rod Measurer (SST 09737-00010) on gasket and lower pin until it touches master cylinder piston.
2. Without moving pin, invert master/booster push rod measurer, and set it on power brake unit. Measure clearance between power brake unit push rod and pin. Clearance should be zero. If clearance is not zero, adjust power brake unit push rod length until push rod lightly touches pin head.

ES300

1. With a force of 66 lbs. (30 kg), depress parking brake pedal while counting clicks. If 3-6 clicks are not counted, parking brake requires adjustment.
2. Remove console upper panel and console box. Ensure parking brake pedal is released. Hold screw end of No. 4 cable to prevent rotation. Loosen lock nut. Hold parking brake cable, and turn adjusting hexagon until pedal travel is correct.
3. Hold adjusting hexagon and tighten lock nut to 48 INCH lbs. (5.4 N.m). Install console box and console upper panel.

GS300 & GS430

With a force of 66 lbs. (30 kg), push depress parking brake pedal while counting clicks. If 7-9 clicks are not counted, parking brake requires adjustment. Loosen lock nut, and turn adjusting nut until pedal travel is correct. Tighten lock nut to 48 INCH lbs. (5.4 N.m).

IS300

1. With a force of 44 lbs. (30 kg), push depress parking brake pedal while counting clicks. If 5-8 clicks are not counted, parking brake requires adjustment.
2. Remove parking brake lever hole cover. Loosen lock nut and turn adjusting nut until lever travel is correct. Tighten lock nut to 48 INCH lbs. (5.4 N.m). Install parking brake lever hole cover.

LS430

With a force of 68 lbs. (31 kg), push depress parking brake pedal while counting clicks. If 6-8 clicks are not counted, parking brake requires adjustment. Loosen lock nut, and turn adjusting nut until pedal travel is correct. Tighten lock nut to 53 INCH lbs. (6.0 N.m).

RX300

1. With a force of 66 lbs. (30 kg), push depress parking brake while counting clicks. If 5-7 clicks are not counted, parking brake requires adjustment.
2. Ensure parking pedal is released. Hold turnbuckle and loosen lock nut on brake cable. To adjust parking brake pedal travel, rotate turnbuckle until 5-7 clicks can be counted on parking brake pedal. Hold turn buckle and tighten lock nut to 44 INCH lbs. (5.0 N.m).

POWER BRAKE UNIT

Release parking brake. With engine running, depress brake pedal and measure pedal reserve distance. Reserve distance is distance from floor pan to brake pedal when fully depressed. See MINIMUM BRAKE PEDAL RESERVE DISTANCE SPECIFICATIONS table. If reserve distance is incorrect, check brake booster for leaks and/or booster push rod out of adjustment.

MINIMUM BRAKE PEDAL RESERVE DISTANCE SPECIFICATIONS

MASTER CYLINDER

Note. GS300 and GS430 models DO NOT have a master cylinder unit. These models have a hydraulic brake booster unit.

Note. The GS300 and GS430 do not have a master cylinder unit. These models use a hydraulic brake booster unit.

Scheme 15

1. Using a screwdriver, remove master cylinder boot. Turn reservoir cap to the OPEN side and remove it. Remove strainer. Remove master cylinder. See «MASTER CYLINDER»(ref-127897-S18110191342001103000000) under REMOVAL & INSTALLATION. Place master cylinder in a soft-jaw vise. Remove brake reservoir set screw. Remove brake fluid reservoir. Remove 2 grommets. (Scheme 15)
2. Push in piston using screwdriver, and remove straight pins by turning over cylinder body. Remove No. 1 piston stopper bolt and gasket. Remove No. 2 piston stopper bolt. (Scheme 15) Remove 2 pistons and springs by hand, pulling straight out, not on an angle. DO NOT score cylinder wall when removing piston and spring. If piston binds, place a rag and 2 wooden blocks on a work bench. Remove No. 1 piston and spring by lightly tapping master cylinder against blocks.

HYDRAULIC BRAKE BOOSTER

Note. Hydraulic brake booster is only used on GS300 and GS430. (Scheme 16)

Scheme 16