Kia Forte: Brake System

Service Data

Item	Specification
Master Cylinder
Type	Single
Cylinder Inner Diameter	Ø 22.22 mm (0.875 in.)
Piston Stroke	45 ± 1 mm (1.77 ± 0.039 in.)
Fluid Level Sensor	Provided
Brake booster
Type	10-inch Single
Booster Ratio	8:1
Front Disc Brake (15 inch)
Type	Ventilated Disc
Rear Disc	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
Rear Disc	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	10.0 mm (0.3937 in.)
Disc Service Limit	8.4 mm (0.3307 in.)
Cylinder Type	Single piston
Drum Brake
Type	Leading Trailing
Drum (Disc) ID	Ø 203.2 mm (8 in.)
Lining Thickness	4.3 mm (0.1693 in)
Parking Brake
Type	BIR (Ball in Ramp)
Activation	Lever

Specifications (ABS)

Part	Item	Standard Value	NOTE
HECU	System	4-Channel 4-Sensor (Solenoid)
	Type	Motor, Integrated Valve Relay Type
	Operating Voltage	10 - 16 V
	Operating Temperature	-40 to 120 °C
	Engine Power	230 W
Active Wheel Speed Sensor (ABS)	Supply Voltage	4.5–20 V DC
	Low Output Current	5.9–8.4 mA
	High Output Current	11.8–16.8 mA
	Output range	1 - 2500 Hz
	Air gap	0.4 - 1.0 mm

Specifications (ESC)

Part	Item	Standard Value	NOTE
HECU	System	4-Channel 4-Sensor (Solenoid)	Full Control
	Type	Motor, Integrated Valve Relay Type	(ABS, HAC, VSM)
	Operating Voltage	10 - 16 V
	Operating Temperature	-40 to 120 °C
	Engine Power	270 W
Active wheel speed sensor	Supply Voltage	5–16 V DC
	Low Output Current	5.9–8.4 mA
	High Output Current	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 travel	135 mm (5.3150 in.)
Stop Lamp Switch Clearance	1.0–2.0 mm (0.04–0.08 in.)
Front Disc Brake Pad Thickness (15 inch)	11.0 mm (0.4331 in.)
Front Disc Brake Pad Maximum Wear Limit (15 inch)	2.0 mm (0.0787 in.)
Front Disc Brake Pad Thickness (16 inch)	11.5 mm (0.4528 in.)
Front Disc Brake Pad Maximum Wear Limit (16 inch)	2.0 mm (0.0787 in.)
Rear brake pad thickness	9.0 mm (0.3543 in.)
Rear brake pad wear limit	2.0 mm (0.0787 in.)

Tightening Torque

Tightening torque

Items		N·m	kgf·m	lbf·ft
Master Cylinder to Brake Booster Nut		9,8 - 15,7	1,0 - 1,6	7,2 - 11,6
Brake Booster to Brake Pedal Bracket Nut		16,7 - 25,5	1,7 - 2,6	12,3 - 18,8
Brake Tube Flare Nuts at Master Cylinder	ABS	12,7 - 16,7	1,3 - 1,7	9,4 - 12,3
Brake Tube Flare Nuts at Master Cylinder	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 steering knuckle		78,5 - 98,1	8,0 - 10,0	57,9 - 72,3
Rear Caliper Assembly with Rear Carrier		78,5 - 98,1	8,0 - 10,0	57,9 - 72,3
Rear Caliper Assembly with 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 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

Lubricants

Items	Recommended	Quantity
Brake fluid	DOT 3 or DOT 4	505.5 ± 20 cc (30.85 ± 1.22 cu. in.)
Brake pedal bushing and bolt	Chassis grease	As required
Parking brake shoe and backing plate contact surface	Heat-resistant grease	As required

Special Service Tools

Tool Name/Number	Illustration	Description
Piston Expander 09581-2T100		Front Disc Brake Piston Compression
SCC reflector 09964-C1100		SCC Radar Alignment Reflector
Calibration beam 09964-C1200		Laser for determining vehicle center.
Stand 09964-C1300		SCC reflector or vertical/horizontal laser support.
Sensor Cover Installer 09527-AL200		Used to install the wheel speed sensor cover (Sensor cover: Φ65.3)

Troubleshooting

Symptom Table

Use the table below to find the cause of the problem. The numbers indicate the priority of the likely cause.

Check each part in order.

If necessary, replace these parts.

Symptom	Possible Cause	Countermeasure
Low or Spongy Pedal	Brake System (Fluid Leak)	Repair
	Brake System (Air Intrusion)	Bleeding Procedure
	Piston Seal (Worn or Damaged)	Replace
	Rear Brake Shoe Clearance (Incorrect Adjustment)	Adjust
	Master Cylinder (Malfunction)	Replace
Brake Drag	Brake Pedal Free Travel (Minimum)	Adjust
	Parking Brake Cable Length (Adjustment Problem)	Adjust
	Parking Brake Cable (Seized)	Repair
	Rear Brake Shoe Clearance (Adjustment Problem)	Adjust
	Lining and Backing Plate (Twisted or Cracked)	Replace
	Piston (Trapped)	Replace
	Piston (Seized)	Replace
	Anchor or Return Spring (Malfunction)	Replace
	Brake Booster (Vacuum Leak)	Repair
	Master Cylinder (Malfunction)	Replace
Uneven Braking	Piston (Trapped)	Replace
Uneven Braking	Lining and Backing Plate (Oil Stains, Cracks or Warpage)	Replace
Heavy Pedal Effort and Brake Problems	Brake System (Fluid Leak, Air Intrusion)	Perform the Bleeding Procedure
	Brake Shoe or Lining (Worn)	Replace
	Pad Shim or Backing Plate (Cracked or Twisted)	Replace
	Rear Brake Shoe Clearance (Adjustment Problem)	Adjust
	Pad Shim or Backing Plate (Oil Stain)	Replace
	Pad Shim or Backing Plate (Slippery)	Replace
	Disc (Scored)	Replace
	Brake Booster (Vacuum Leak)	Repair
Brake noise	Pad Shim or Backing Plate (Cracked or Twisted)	Replace
	Loose Wheel Bolt and Caliper	Adjust
	Pad Sliding Problems (Uneven Pad Wear)	Replace
	Lining or Backing Plate (Dirty)	Cleaning
	Pad Shim or Backing Plate (Slippery)	Brake Pad Replacement
	Anchor or Return Spring (Malfunction)	Replace
	Brake Pad Shim (Damaged)	Replace
	Retaining Spring (Damaged)	Replace
	Foreign Object Caught Between Disc and Pad	Cleaning
	Corrosion on Disc	Brake Road Test and Cleaning * Remove friction corrosion by performing a brake road test
	Cave-in Disc	Replace
Brakes Not Fully Effective (at high driving speed)	Brake Shoe or Lining (Worn)	Replace
Brakes Not Fully Effective (at high driving speed)	Master Cylinder (Malfunction)	Replace
Brake Vibration	Brake Booster (Vacuum Leak)	Repair
	Pedal Free Separation	Adjust
	Master Cylinder (Malfunction)	Replace
	Master Cylinder Cap Damaged	Replace
	Brake Line Damaged	Replace
	Caliper Return Problem (while wheel rotates, check for noise)	Replace
	Converted Disc	Replace

Brake Bleeding Procedures

Brake Bleeding

1
Make sure the brake fluid level in the reservoir is at the MAX (upper) level line.
2
Have someone slowly depress the brake pedal several times, then hold the pressure.
3
Loosen the right rear brake bleeder screw (A) to allow air to escape from the system. Then securely tighten the bleeder screw.

Front

Rear
4
Repeat the procedure for each wheel in the sequence shown below until no more air bubbles appear in the fluid.
5
Fill the master cylinder reservoir to the MAX (upper) level mark.

ESC Brake Bleeding

This procedure must be performed to ensure proper air bleeding and filling of the ESC unit, brake lines, and master cylinder with brake fluid.

1
Remove the reservoir cap and fill the reservoir with brake fluid.
NOTE
- If brake fluid gets on a painted surface, wash it off immediately.
- Do not depress the brake pedal when releasing pressure.
Recommended fluid: DOT 3 or DOT 4.
2
Connect a clear plastic tube to the wheel cylinder bleeder screw and insert the other end of the tube into a clear plastic bottle half-filled with brake fluid.
3
Connect the KDS to the data link connector located under the instrument panel.
4
Select and follow the instructions on the KDS screen.
5
Depress the brake pedal several times, then loosen the bleeder screw to bleed air until fluid flows out without bubbles. Then close the bleeder screw (A).

Front

Rear
6
Repeat step 5 until there are no air bubbles in the fluid for each wheel.
7
Fill the master cylinder reservoir to the MAX (upper) level mark.