Lexus GS300/400 (2000 year). Manual — part 100

BR0JA–09

BR–2

–

BRAKE

TROUBLESHOOTING

2110

TROUBLESHOOTING

PROBLEM SYMPTOMS TABLE

Use the table below to help you find the cause of the problem. The numbers indicate the priority of the likely
cause of the problem. Check each part in order. If necessary, replace these parts.

Symptom

Suspect Area

See page

Low pedal or spongy pedal

6. Fluid leaks for brake system

7. Air in brake system

8. Piston seals (Worn or damaged)

9. Hydraulic brake booster (Faulty)

DI–516

BR–4

BR–18

BR–27

BR–38

Brake drag

1. Brake pedal freeplay (Minimum)

2. Parking brake pedal travel (Out of adjustment)

3. Parking brake wire (Sticking)

4. Parking brake (Shoe clearance out of adjustment)

5. Pad (Cracked or distorted)

6. Piston (Stuck)

7. Piston (Frozen)

8. Tension or return spring (Faulty)

9. Hydraulic brake booster (Faulty)

BR–9

BR–11

–

BR–37

BR–15

BR–24

BR–18

BR–27

BR–18

BR–27

BR–33

BR–38

Brake pull

1. Piston (Stuck)

2. Pad (Cracked or distorted)

3. Piston (Frozen)

4. Disc (Scored)

5. Pad (Cracked or distorted)

6. Hydraulic brake booster (Faulty)

BR–18

BR–27

BR–15

BR–24

BR–18

BR–27

BR–18

BR–27

BR–15

BR–24

BR–38

Hard pedal but brake inefficient

1. Fluid leaks for brake system

2. Air in brake system

3. Pad (Worn)

4. Pad (Cracked or distorted)

5. Pad (Oily)

6. Pad (Glazed)

7. Disc (Scored)

8. Hydraulic brake booster (Faulty)

DI–516

BR–4

BR–15

BR–24

BR–15

BR–24

BR–15

BR–24

BR–15

BR–24

BR–18

BR–30

BR–38

–

BRAKE

TROUBLESHOOTING

BR–3

2111

Noise from brakes

1. Pad (Cracked or distorted)

2. Installation bolt (Loose)

3. Disc (Scored)

4. Pad support plate (Loose)

5. Sliding pin (Worn)

6. Pad (Dirty)

7. Pad (Glazed)

8. Tension or return spring (Faulty)

9. Anti–squeal shim (Damaged)

10.Shoe hold–down spring (Damaged)

BR–15

BR–24

BR–15

BR–24

BR–18

BR–27

BR–18

BR–18

BR–15

BR–24

BR–15

BR–24

BR–33

BR–18

BR–27

BR–33

Noise from hydraulic brake booster

(Abnormal pump motor operation noise)

Accumulator bracket clearance (Out or adjustment)

BR–56

Brake warning light lights up*

1

(Parking brake pedal released)

1. Brake fluid level

2. Hydraulic brake booster power supply system (Faulty)

BR–38

Brake warning light lights up and brake warning buzzer sounds*

2

Hydraulic brake booster power supply system (Faulty)

BR–38

ABS warning light lights up*

3

1. Anti–lock brake system (Faulty)

2. Hydraulic brake booster power supply system (Faulty)

BR–38

*

1

, *

3

:

The light may stay on for about 60 seconds after the engine has been started. It is normal if it goes

out after a while.
*

2

, *

3

: Depressing the brake pedal repeatedly may turn on the warning light and buzzer. It is normal if the

light goes out and the buzzer stops sounding after a few seconds.
*

3

: While ABS warning light is ON, both VSC warning light and VSC OFF indicator light come on.

BR0JM–07

F01627

F01630

F01631

–

BRAKE

FRONT BRAKE CALIPER

BR–21

2129

INSPECTION

1.

MEASURE PAD LINING THICKNESS

Using a ruler, measure the pad lining thickness.

Standard thickness: 11.0 mm (0.433 in.)
Minimum thickness: 1.0 mm (0.039 in.)

Replace the pad if the thickness is less than the minimum (the
1.0 mm slit is no longer visible), or if it shows signs of uneven
wear.

2.

MEASURE DISC THICKNESS

Using a micrometer, measure the disc thickness.

Standard thickness: 32.0 mm (1.260 in.)
Minimum thickness: 30.0 mm (1.181 in.)

Replace the disc if the thickness of the disc is at the minimum
thickness or less. Replace the disc or grind it on a lathe if it is
scored or is worn unevenly.

3.

MEASURE DISC RUNOUT

(a)

Temporarily fasten the disc with the 3 hub nuts.

(b)

Using a dial indicator, measure the disc runout at a posi-
tion 10 mm (0.39 in.) away from the out side edge.
Maximum disc runout: 0.05 mm (0.0020 in.)

If the disc’s runout is maximum value or greater, check the bear-
ing play in the axial direction and check the axle hub runout
(See page

SA–10

). If the bearing play and axle hub runout are

not abnormal, adjust the disc runout or grind it on a ”On–Car”
brake lathe.
4.

IF NECESSARY, ADJUST DISC RUNOUT

(a)

Remove the 2 bolts and torque plate.

(b)

Remove the 3 hub nuts and disc. Turn the disc 1/5 turn
and reinstall the disc. Install and torque the 3 hub nuts.
Torque: 103 N·m (1,050 kgf·cm, 76 ft·lbf)

(c)

Remeasure the disc runout. Make a note of the runout
and the disc’s position on the hub.

(d)

Repeat (b) until the disc has been installed on the 3 re-
maining hub positions.

(e)

If the minimum runout recorded in (b) and (c) is less than
0.05 mm (0.0020 in.), install the disc in that position.

(f)

If the minimum runout recorded in (b) and (c) is greater
than 0.05 mm (0.0020 in.), replace the disc and repeat
step 3.

(g)

Install the torque plate and torque the 2 bolts.
Torque: 118 N·m (1,200 kgf·cm, 87 ft·lbf)

BR0JN–05

BR–22

–

BRAKE

FRONT BRAKE CALIPER

2130

REASSEMBLY

Reassembly is in the reverse order of disassembly (See page

BR–20

).

HINT:
Apply lithium soap base glycol grease to the parts indicated by the arrows (See page

BR–18

).