Brake system
Precautions Troubleshooting Removal / installation
BRAKE SYSTEM/PEDAL/BRAKE BOOSTER DEVICE
BRAKE SYSTEM
PRECAUTIONS
1. The speed sensor FR and RR are easily affected by magnetism. Use extra caution when working with magnets.
2. Replace each part correctly. Otherwise it may impair the brake system, leading to dangerous driving conditions. Use the same part or the equivalent for replacement.
3. When servicing the brake system, keep the parts and their surroundings clean.
4. If the vehicle is equipped with a device including a radio, refer to the precautions in “General” section.
FUNCTION INSPECTION
1. Brake booster simple check
(1) Function inspection of brake booster air-tightness
(a) Start the engine, let it idle for 1 to 2 minutes, and then stop it.
(b) Depress the brake pedal several times with an ordinary force, and check the height change of the brake pedal.
Criteria
: The brake pedal height goes up each time the pedal is depressed (The intervals between the first and second time, and the second and third time are 5 seconds or more).
(2) Brake booster operation check
(a) Depress the brake pedal several times in the same force with the engine turned OFF, and check that there is no height change in the brake pedal.
(b) With the brake pedal depressed, start the engine and check the height change of the brake pedal.
Criteria
: When the engine is started with the brake pedal depressed, the brake pedal travels a little farther.
(3) Function inspection of brake booster load air tightness
(a) With the engine running, press and hold the brake pedal and stop the engine for 30 seconds to check the height change of the brake pedal.
Criteria
: No height change in the pedal
2. Function inspection of brake booster
(1) Preparation for inspection
Captions in illustration
| *1 |
Pressure gauge |
*2 |
Vacuum gauge |
| *3 |
Adapter hose |
*4 |
Vacuum hose |
| *5 |
Pedal force gauge |
(2) Function inspection of air tightness
(a) Start the engine and then stop the engine at the vacuum pressure of 66.7 kPa {500 mmHg} {19.69 inHg} to check the vacuum pressure change.
Criteria
: Vacuum pressure does not drop for 15 seconds.
(3) Function inspection of load air tightness
(a) Start the engine and depress the brake pedal at a pedal force of 196 N {20 kgf} {44.1l bf}. Then stop the engine at the vacuum pressure of 66.7 kPa {500 mmHg} to check the vacuum pressure change.
Criteria
: Vacuum pressure drops to within 3.3 kPa{25 mmHg} {0.97 inHg} for 15 seconds.
(4) Non-boosting action check
(5) Boosting action check
(a) Start the engine and increase the vacuum pressure up to 66.7 kPa{500 mmHg} in the brake booster, and then check the fluid pressure in each pedal force.
Standard value
| Pedal force [N{kgf, lbf}] |
Fluid pressure [MPa{kgf/cm2, psi}] |
|---|---|
| 147 {15, 33.1} |
105 {1075, 1522.5} |
| 294 {33, 66.1} |
112 {1146, 1624.0} |
NOTE:
If the brake booster ASSY is faulty, check the check valve. If there is no problem with the check valve, replace the brake booster ASSY.
(6) Remove the pressure gauge, pedal force gauge, and vacuum gauge.
(7) Install the vacuum hose to the brake booster ASSY.
(8) Air bleeding of brake system (Refer to 
)
)SYMPTOM TABLE
Brake system
| Symptoms |
Inspection items |
Reference pages |
|---|---|---|
| Pedal sinks/Pedal pressure is soft. |
Brake system (fluid leakage) |
- |
| Brake system (air entry) |
|
|
| Front brake piston seal (wear or breakage) |
|
|
| Rear brake piston seal (wear or breakage) |
|
|
| Master cylinder (faulty) |
|
|
| Brake drag |
Brake pedal play (minimum) |
|
| Parking brake lever stroke (improper adjustment) |
|
|
| Parking brake cable ASSY No.1 (sticking) |
|
|
| Parking brake cable ASSY No.2 (sticking) |
|
|
| Parking brake cable ASSY No.3 (sticking) |
|
|
| Parking brake shoe clearance (improper adjustment) |
|
|
| Front brake pad (crack or deformation) |
|
|
| Rear brake pad (crack or deformation) |
|
|
| Front brake piston (sticking) |
|
|
| Rear brake piston (sticking) |
|
|
| Front brake piston (seizure) |
|
|
| Rear brake piston (seizure) |
|
|
| Air leakage in booster |
|
|
| Master cylinder (faulty) |
|
|
| Brake working on one-side |
Front brake piston (sticking) |
|
| Rear brake piston (sticking) |
|
|
| Front brake pad (oil stain) |
|
|
| Rear brake pad (oil stain) |
|
|
| Front brake piston (seizure) |
|
|
| Rear brake piston (seizure) |
|
|
| Front disc (uneven wear) |
|
|
| Rear disc (uneven wear) |
|
|
| Front brake pad (crack or deformation) |
|
|
| Rear brake pad (crack or deformation) |
|
|
| Pedal is hard but the brake does not work well. |
Brake system (fluid leakage) |
- |
| Brake system (air entry) |
|
|
| Front brake piston (sticking) |
|
|
| Rear brake piston (sticking) |
|
|
| Front brake pad (crack or deformation) |
|
|
| Rear brake pad (crack or deformation) |
|
|
| Front brake pad (oil stain) |
|
|
| Rear brake pad (oil stain) |
|
|
| Front brake pad (burn in) |
|
|
| Rear brake pad (burn in) |
|
|
| Front disc (uneven wear) |
|
|
| Rear disc (uneven wear) |
|
|
| Air leakage in booster |
|
|
| Noise from brake |
Front brake pad (crack or deformation) |
|
| Rear brake pad (crack or deformation) |
|
|
| Front brake mounting bolt (looseness) |
|
|
| Rear brake mounting bolt (looseness) |
|
|
| Front disc (scratch) |
|
|
| Rear disc (scratch) |
|
|
| Front pad support plate (looseness) |
|
|
| Front slide pin (wear) |
|
|
| Front brake pad (dirt) |
|
|
| Rear brake pad (dirt) |
|
|
| Front brake pad (burn in) |
|
|
| Rear brake pad (burn in) |
|
|
| Front anti squeal shim (breakage) |
|
|
| Rear anti squeal shim (breakage) |
|