| SONATA(YF) >2012 > G 2.4 GDI > Brake System > Brake System>Repair procedures |

Operation and Leakage Check

Check all of the following items:

Component | Procedure
Brake Booster (A) | Check brake operation by applying the brakes during a test drive. If the brakes do not work properly, check the brake booster. Replace the brake booster as an assembly if it does not work properly or if there are signs of leakage.
Piston cup and pressure cup inspection (B) |

• | Check brake operation by applying the brakes. Look for damage or signs of fluid leakage. Replace the master cylinder as an assembly if the pedal does not work properly or if there is damage or signs of fluid leakage.

• | Check for a difference in brake pedal stroke between quick and slow brake applications. Replace the master cylinder if there is a difference in pedal stroke.

Brake hoses (C) | Look for damage or signs of fluid leakage. Replace the brake hose with a new one if it is damaged or leaking.
Caliper piston seal and piston boots (D) | Check brake operation by applying the brakes. Look for damage or signs of fluid leakage. If the pedal does not work properly, the brakes drag, or there is damage or signs of fluid leakage, disassemble and inspect the brake caliper. Replace the boots and seals with new ones whenever the brake caliper is disassembled.

Brake System Bleeding

• | Do not reuse the drained fluid.

• | Always use genuine DOT3/DOT4 brake Fluid. Using a non-genuine DOT3/DOT4 brake fluid can cause corrosion and decrease the life of the system.

• | Make sure no dirt or other foreign matter is allowed to contaminate the brake fluid.

• | Do not spill brake fluid on the vehicle, it may damage the paint; if brake fluid does contact the paint, wash it off immediately with water.

• | The reservoir on the master cylinder must be at the MAX (upper) level mark at the start of bleeding procedure and checked after bleeding each brake caliper. Add fluid as required.

1. | Make sure the brake fluid in the reservoir is at the MAX(upper) level line.

2. | Have someone slowly pump the brake pedal several times, and then apply pressure.

3. | Loosen the right-rear brake bleed screw (A) to allow air to escape from the system. Then tighten the bleed screw securely. Front Rear

4. | Repeat the procedure for wheel in the sequence shown below until air bubbles no longer appear in the fluid.

5. | Refill the master cylinder reservoir to MAX(upper) level line.

Fluid can be overflowed when it is refilled with used brake pad.