Kia Forte: Brake System

Kia Forte 2019-2024 (BD) Service Manual / Brake System

Service data

Service Data

Item	Specification
Master cylinder
Type	Single
Cylinder I.D.	Ø 22.22 mm (0.875 in)
Piston stroke	45±1 mm (1.77 ± 0.039 in)
Fluid level switch	Provided
Brake booster
Type	10" Single
Boosting ratio	8:1
Front disc brake (15 inch)
Type	Ventilated disc
Disc O.D.	280 mm (11.0236 in)
Disc thickness	23 mm (0.9055 in)
Disc Service Limit	21 mm (0.8268 in)
Cylinder type	Single piston
Front disc brake (16 inch)
Type	Ventilated disc
Disc O.D.	305 mm (12.0079 in)
Disc thickness	25.0 mm (0.9843 in)
Disc Service Limit	23.4 mm (0.9213 in)
Cylinder type	Single piston
Rear disc brake
Type	Solid disc
Disc O.D	262 mm (10.3149 in)
Disc thickness	10.0mm (0.3937 in)
Disc Service Limit	8.4mm (0.3307 in)
Cylinder type	Single piston
Drum brake
Type	Leading trailing
Drum(Disc) I.D	Ø 203.2 mm (8 in)
Brake lining thickness	4.3 mm (0.1693 in)
Parking brake
Type	BIR (Ball-in-Ramp)
Actuation	Lever

O.D. : Outer Diameter

I.D : Inner Diameter

Specification (ABS)

Part	Item	Standard value	Remark
HECU	System	4 Channel 4 Sensor (Solenoid)
	Type	Motor, valve relay integrated type
	Operating Voltage	10 - 16 V
	Operating Temperature	-40 to 120 °C (-40 to 248°F)
	Motor power	230 W
Active Wheel speed sensor (ABS)	Supply voltage	DC 4.5 - 20 V
	Output current low	5.9 - 8.4 mA
	Output current high	11.8 - 16.8 mA
	Output range	1 - 2500 Hz
	Air gap	0.4 - 1.0 mm

Specification (ESC)

Part	Item	Standard value	Remark
HECU	System	4 Channel 4 Sensor (Solenoid)	Total control
	Type	Motor, valve relay integrated type	(ABS, HAC, VSM)
	Operating Voltage	10 - 16 V
	Operating Temperature	-40 to 120 °C (-40 to 248°F)
	Motor power	270 W
Active Wheel speed sensor	Supply voltage	DC 5 - 16 V
	Output current low	5.9 - 8.4 mA
	Output current high	11.8- 16.8 mA
	Output range	0 - 2500 Hz
	Tone wheel	46 teeth
	Air gap	0.4 - 1.0 mm

Service Standard

Items	Standard value
Brake pedal height	183 mm (7.2047 in)
Brake pedal Full stroke	135 mm (5.3150 in)
Stop lamp clearance	1.0 - 2.0 mm (0.04 - 0.08 in)
Front brake disc pad thickness (15 inch)	11.0 mm (0.4331 in)
Front brake disc pad service limit (15 inch)	2.0 mm (0.0787 in)
Front brake disc pad thickness (16 inch)	11.5 mm (0.4528 in)
Front brake disc pad service limit (16 inch)	2.0 mm (0.0787 in)
Rear brake disc pad thickness	9.0 mm (0.3543 in)
Rear brake disc pad service limit	2.0 mm (0.0787 in)

Tightening torque

Tightening Torques

Items		N·m	kgf·m	lb·ft
Master cylinder to brake booster nut		9.8 - 15.7	1.0 - 1.6	7.2 - 11.6
Brake booster to brake pedal nut		16.7 - 25.5	1.7 - 2.6	12.3 - 18.8
Master cylinder tube flare nuts	ABS	12.7 - 16.7	1.3 - 1.7	9.4 - 12.3
Master cylinder tube flare nuts	ESC	18.6 - 22.6	1.9 - 2.3	13.7 - 16.6
HECU bracket mounting bolts		16.7 - 25.5	1.7 - 2.6	12.3 - 18.8
HECU brake tube flare nuts	ABS	12.7 - 16.7	1.3 - 1.7	9.4 - 12.3
HECU brake tube flare nuts	ESC	18.6 - 22.6	1.9 - 2.3	13.7 - 16.6
Front caliper guide rod bolts		21.6 - 31.4	2.2 - 3.2	15.9 - 23.1
Rear caliper guide rod bolts		21.6 - 31.4	2.2 - 3.2	15.9 - 23.1
Front caliper assembly to knuckle		78.5 - 98.1	8.0 - 10.0	57.9 - 72.3
Rear caliper assembly to rear carrier		78.5 - 98.1	8.0 - 10.0	57.9 - 72.3
Rear caliper assembly to torsion beam axle		63.7 - 73.5	6.5 - 7.5	47.0 - 54.2
Brake hose to caliper bolt		24.5 - 29.4	2.5 - 3.0	18.1 - 21.7
Brake pedal member bracket nuts		16.7 - 25.5	1.7 - 2.6	12.3 - 18.8
Wheel speed sensor mounting bolt		8.8 - 13.7	0.9 - 1.4	6.5 - 10.1

Lubricant

Lubricants

Items	Recommended	Amount
Brake fluid	DOT 3 or DOT 4	505.5 ± 20cc (30.85 ± 1.22 cn.in)
Brake pedal bushing and bolt	Chassis grease	As required
Parking brake shoe and backing plate contacting surface	Heat resistance grease	As required

Special service tools

Special Service Tools

Tool Name / Number	Illustration	Description
Piston expander 09581-2T100		Spreading the front disc brake piston
SCC reflector 09964-C1100		Reflector to align the SCC radar
Calibration beam 09964-C1200		Laser to detect the center of the vehicle.
Tripod 09964-C1300		SCC reflector or vertical / horizontal laser support.
Sensor cap installer 09527-AL200		Used for installing wheel speed sensor cap (Sensor cap : Φ65.3)

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	Expected cause	Countermeasure
Lower pedal or sponge pedal	Brake system (oil leakage)	Repair
	Brake system (air inflow)	Air bleeding out procedure
	Piston seal (worn out or damaged)	Replace
	Rear brake shoe separation (faulty adjustment)	Adjust
	Master cylinder (malfunction)	Replace
Dragged brake	Brake pedal free separation (minimum)	Adjust
	Parking brake cable length (adjustment trouble)	Adjust
	Parking brake cable (trapped)	Repair
	Rear brake shoe separation (adjustment trouble)	Adjust
	Pad and lining (twisted or cracked)	Replace
	Piston (trapped)	Replace
	Piston (frozen)	Replace
	Anker or return spring (malfunction)	Replace
	Booster system (leakage of vacuum)	Repair
	Master cylinder (malfunction)	Replace
Uneven brake	Piston (trapped)	Replace
Uneven brake	Pad and lining (oil stain, cracked or twisted)	Replace
Heavy pedal and brake trouble	Brake system (oil leakage, air inflow)	Perform air bleeding procedure
	Pad or lining (worned out)	Replace
	Pad or lining (cracked or twisted)	Replace
	Rear brake shoe separation (adjustment trouble)	Adjust
	Pad or lining (oil stain)	Replace
	Pad or lining (slippery)	Replace
	Disc (scratched)	Replace
	Booster system (leakage of vacuum)	Repair
Noise from brake	Pad or lining (cracked or twisted)	Replace
	Looseness of wheel bolt and caliper	Adjust
	Pad sliding trouble (Pad uneven worn out)	Replace
	Pad or lining (dirty)	Cleaning
	Pad or lining (slippery)	Pad replacement
	Anker or return spring (malfunction)	Replace
	Brake pad shim (damaged)	Replace
	Hold down spring (damaged)	Replace
	Foreign substance stucked between disc and pad	Cleaning
	Corrosion on disc	Test drive brake and cleaning * get rid of corrosion by friction while test drive brake
	Caved disc	Replace
Not fully functioning on brake (when drive speed is fast)	Pad or lining (worned out)	Replace
Not fully functioning on brake (when drive speed is fast)	Master cylinder (malfunction)	Replace
Brake vibration	Brake booster (leakage of vacuum)	Repair
	Pedal free separation	Adjust
	Master cylinder (malfunction)	Replace
	Damaged on master cylinder cap	Replace
	Damaged on brake line	Replace
	Caliper returning trouble (while tire is turning, check the noise)	Replace
	Transformed disc	Replace

Brake bleeding prcoedures

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 that no dirt or other foreign matter is allowed to contaminate the brake fluid.

•	Do not spill brake fluid on the vehicle as it may damage the paint. If brake fluid comes in contact with the paint, wash 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 that the brake fluid in the reservoir is at the MAX (upper) level line.

2.	Have someone to 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.

Bleeding of ESC Brake System

This procedure should be followed to ensure adequate bleeding of air and filling of the ESC unit, brake lines and master cylinder with brake fluid.

Remove the reservoir cap and fill the brake reservoir with brake fluid.

•	If there is any brake fluid on any painted surface, wash it off immediately.

•	When pressure bleeding, do not depress the brake pedal.

Recommended fluid : DOT3 or DOT4

2.	Connect a clear plastic tube to the wheel cylinder bleeder plug and insert the other end of the tube into a half filled clear plastic bottle.

3.	Connect the KDS to the data link connector located underneath the dash panel.

4.	Select and operate according to the instructions on the KDS screen.

5.	Pump the brake pedal several times, and then loosen the bleeder screw until fluid starts to run out without bubbles. Then close the bleeder screw (A). Front Rear

6.	Repeat step 5 until there are no more bubbles in the fluid for each wheel.

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

Brake System

Parking Brake System

ABS(Anti-Lock Brake System)

ESC (Electronic Stability Control) System

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