Hyundai Sonata LF: Brake System / Repair procedures

Hyundai Sonata LF 2014-2019 Service Manual / 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]

[General]

[EPB]

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.

    Brake System

    ..

    Brake Booster Components and Components Location

    C..

    Other information:

    Hyundai Sonata LF 2014-2019 Service Manual: Description and Operation


    Description BSD is a system that uses two magnetic wave radar sensors attached on the rear panel to measure the distance from the following vehicles and provides the sensing and (visual and auditory) alarm of any vehicle coming into the blind spot...

    Hyundai Sonata LF 2014-2019 Service Manual: Troubleshooting


    Trouble Symptom Charts Trouble Symptom 1 Trouble Symptom 2 Trouble symptomProbable causeRemedyThe set vehicle speed varies greatly upward or downward"Surging" (repeated alternating acceleration and deceleration) occurs after settingMalfunction of the vehicle speed sensor circuitRepair the vehicle speed sensor system, or replace the partMalfunction of ECMCheck input and output signals at ECM Trouble Symptom 3 Trouble symptomProbable causeRemedyThe CC system is not canceled when the brake pedal is depressedDamaged or disconnected wiring of the brake pedal switchRepair the harness or replace the brake pedal switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 4 Trouble symptomProbable causeRemedyThe CC system is not canceled when the shift lever is moved to the "N" position (It is canceled, however, when the brake pedal is depressed)Damaged or disconnected wiring of inhibitor switch input circuitRepair the harness or repair or replace the inhibitor switchImproper adjustment of inhibitor switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 5 Trouble symptomProbable causeRemedyCannot decelerate (coast) by using the "SET/–" switchTemporary damaged or disconnected wiring of "SET/–" switch input circuitRepair the harness or replace the "SET/–" switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 6 Trouble symptomProbable causeRemedyCannot accelerate or resume speed by using the "RES/+" switchDamaged or disconnected wiring, or short circuit, or "RES/+" switch input circuitRepair the harness or replace the "RES/+" switchMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 7 Trouble symptomProbable causeRemedyCC system can be set while driving at a vehicle speed of less than 40km/h (25mph), or there is no automatic cancellation at that speedMalfunction of the vehicle-speed sensor circuitRepair the vehicle speed sensor system, or replace the partMalfunction of the ECM signalsCheck input and output signals at ECM Trouble Symptom 8 Trouble symptomProbable causeRemedyThe cruise main switch indicator lamp does not illuminate (But CC system is normal)Damaged or disconnected bulb of cruise main switch indicator lampRepair the harness or replace the part...

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