Kia Optima Hybrid: Brake System / Troubleshooting
| Troubleshooting |
| Symptom | Suspect Area | Reference |
| Lower pedal or spongy pedal | 1. Integrated Brake Actuation Unit (Air in) | air·bleed |
| 2. AHB system (Fluid leaks) | replace | |
| 3. Piston seals in IBAU (Worn or damaged) | replace | |
| Brake drag | 1. Brake pedal free play (Minimum) | adjust |
| 2. Pad or lining (Cracked or distorted) | replace | |
| 3. Piston (Stuck) | replace | |
| 4. Piston (Frozen) | replace | |
| 5. Anchor or Return spring (Inoperative) | replace | |
| 6. Master cylinder (Inoperative) | replace | |
| 7. IBAU (Inoperative) | replace | |
| Brake pull | 1. Piston (Sticking) | replace |
| 2. Pad or lining (Oily) | replace | |
| 3. Piston (Frozen) | replace | |
| 4. Disc (Scored) | replace | |
| 5. Pad or lining (Cracked or distorted) | replace | |
| Hard pedal but brake inefficient | 1. Brake system (Fluid leaks) | repair |
| 2. Brake system (Air in) | air·bleed | |
| 3. Pad or lining (Worn) | replace | |
| 4. Pad or lining (Cracked or distorted) | replace | |
| 5. Rear brake shoe clearance(Out of adjustment) | adjust | |
| 6. Pad or lining (Oily) | replace | |
| 7. Pad or lining (Glazed) | replace | |
| 8. Disc (Scored) | replace | |
| 9. IBAU (Inoperative) | replace | |
| 10. PSU (Inoperative) | replace | |
| Noise from brake | 1. Pad or lining (Cracked or distorted) | replace |
| 2. Installation bolt (Loosen) | adjust | |
| 3. Disc (Scored) | replace | |
| 4. Sliding pin (Worn) | replace | |
| 5. Pad or lining (Dirty) | clean | |
| 6. Pad or lining (Glazed) | replace | |
| 7. Brake pad shim (Damage) | replace | |
| Brake fades | 1. Pad or lining (Worn) | replace |
| 2. Master cylinder (Inoperative) | replace | |
| Brake vibration, pulsation | 1. Pedal free play | adjust |
| 2. Master cylinder (Inoperative) | replace | |
| 3. Caliper (Damage) | replace | |
| 4. Master cylinder cap seal | replace | |
| 5. Damaged brake lines | replace | |
| Heavey pedal (Halt) | 1. Brake pedal sticking (lack of grease) | repair |
| 2. IBAU (Inoperative) | replace | |
| Motor sounds and excessive time to braking when consecutive 2 or 3 times pushing brake pedal (In the case of that accumulator pressure increase rate is under 5bar/sec when checking sensor figures of AHB with GDS) | 1. AHB system (air in) | air·bleed |
| 2. PSU(Inoperative) | replace | |
| Excessive noise when pushing brake pedal | 1. IBAU/PSU system (air in) | air·bleed |
It is not the malfunction of brake when motor sound is noticed with followings.
It is not the malfunction of brake while a brake pedal seems inoperative with followings.
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Special Service Tools
Special Service Tools Tool Name / NumberIllustrationDescription09581-11000Piston expanderUsed when spreading the front and rear brake piston.09580-3D100Air bleeding toolUsed when bleeding the air in the ...
Other information:
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