Characteristics and malfunctions of the brakes of the Kia Magentis car
Technical data
Master brake cylinder
- – type - Tandem
- – cylinder diameter, mm:
- CBS 23.8
- ABS 25.4
Vacuum booster brakes
- – type - Vacuum
- – effective diameter, mm:
- CBS 177.8
- ABS 203.2
- – ratio
- CBS 7.0 : 1
- ABS 7.5 : 1
Pressure limiter
- – engagement pressure, MPa 3.43
- – decompression ratio 0.32 : 1
Front brakes
- – type - Disc, ventilated
- – brake disc diameter, mm 257
- – brake disc thickness, mm 24.5
- – brake pad thickness, mm 11
- – cylinder diameter, mm 57.2
Rear drum brakes
- – brake drum inner diameter, mm 228.6
- – brake pad thickness, mm 5
- – cylinder diameter, mm 19.05
Rear disc brakes
- – brake disc diameter, mm 262
- – brake disc thickness, mm 10
- – brake pad thickness, mm 10
- – cylinder diameter, mm 34
Anti-lock braking system brakes
ECU control unit
- – supply voltage, V 10–16
- – temperature range, °C – 40…110
Control lamp: W / ABS , TCS , TCS OFF , EBD
- – supply voltage, V 12
- – current consumption, mA 80
Wheel speed sensor
- – resistance, Ohm 1275–1495
- – output voltage, V 0.15–50
- – air gap, mm 0.2–1.2
Hydraulic unit HECU
- – weight, kg 3.0
- – engine 12 V, 35 A
- – engine power, W 180
- – performance, cm3/s 5.5
Adjustment data
Brake pedal installation height, 176±0.3 mm
Brake light switch clearance, 0.5–1.0 mm
Brake pedal free travel, 3–8 mm
Distance from pressed brake pedal to floor, 44 mm
Brake booster pushrod clearance to master cylinder, mm 0
Parking brake lever travel when tightened with force 196 N 8–9 clicks
Minimum permissible front brake pad thickness, 2.0 mm
Minimum permissible brake disc thickness, 22.4 mm
Brake disc runout, 0.08 mm
Minimum permissible disc thickness difference, 0.01 mm
Minimum permissible rear brake pad lining thickness, 1.5 mm
Maximum permissible brake drum bore diameter, 229.6 mm
Maximum permissible piston clearance in the working brake cylinder, 0.15 mm
Minimum permissible rear disc brake pad lining thickness, 2.0 mm
Lubricants
Brake fluid DOT 3 or equivalent
Brake pedal bushing and bolt - Lubricant SAE J 310, NLGI #0
Cotter pin - Lubricant SAE J 310, NLGI #2
Backplate contact surfaces - Bearing lubricant NLGI #0
Ratchet or pawl moving parts - Lubricant SAE J 310, NLGI #2
Tightening torques, Nm
Master cylinder to bracket nuts 8-12
Master cylinder bracket nuts 13-16
Vacuum hose nipple to air expansion chamber 15–18
Bleed nipple 7–13
Brake pipe union nuts 13–17
Pressure limiter to brake master cylinder 35–55
Caliper guide bushing bolt 22–32
Caliper to steering knuckle mounting bolts 69–85
Hollow bolt for mounting brake hose to front caliper 25–35
Master cylinder mounting bolts 12–18
Front wheel speed sensor 8–9.5
Rear wheel speed sensor 15.5–16.5
ECU and HECU mounting bolts 8–10
ECU and HECU bracket mounting bolts 9–10
Six brake pipes to the hydraulic unit 13–17
Troubleshooting brake problems
Probable cause - Solution
The car pulls to one side when braking:
- - Grease on the brake pads - Replace the brake pads
- - Uneven brake pad contact - Replace the brake pads
- - Malfunction of the automatic brake pad clearance adjustment - Adjust the automatic clearance adjustment mechanism adjusting the brake shoe clearances
- - Warping or uneven wear of the brake drum - Replace the brake drum
Low braking force:
- - Low brake fluid level - Add brake fluid
- - Air in the brake system - Bleed the brake system
- - Overheating of the brakes, leading to a decrease in friction of the brake pads - Replace the brake pads
- - Grease on the brake pads - Replace the brake pads
- - Uneven contact of the brake pad - Replace the brake pads
- - Malfunction of the brake booster - Check the functionality of the brake booster
- - Malfunction of the brake Automatic Brake Pad Clearance Adjuster - Adjust the automatic brake pad clearance adjuster
- - Brake line is clogged - Clean or replace the brake line
- - Pressure regulator malfunction - Replace the pressure regulator
Increased brake pedal travel:
- - Air in the brake system - Bleed the brake system
- - Brake pad wear - Replace the brake pads
- - Vacuum hose is damaged - Replace the vacuum hose
- - Brake fluid leaks - Eliminate brake fluid leaks
- - Automatic Brake Pad Clearance Adjuster malfunction - Adjust the automatic brake pad clearance adjuster
- - Excessive clearance between the brake booster plunger and the brake master cylinder - Adjust the clearance between the brake booster plunger and the brake master cylinder
- - Faulty brake master cylinder - Replace the brake master cylinder
Brake drag:
- - Parking brake not fully released - Adjust the parking brake
- - Incorrect parking brake adjustment - Adjust the parking brake
- - Brake pedal return spring worn - Replace the brake pedal return spring
- - Rear brake shoe tension spring broken - Replace the spring
- - Lack of lubrication in the moving parts of the brake mechanisms - Lubricate the moving parts of the brake mechanisms
- - Excessive clearance between the brake booster plunger and the brake master cylinder - Adjust the clearance between the brake booster plunger and the brake master cylinder
- - The return channel of the brake master cylinder is clogged - Clean the channels of the brake master cylinder
- - The piston return spring is damaged - Replace the spring
The vehicle does not brake reliably with the parking brake:
- - The rear drum brake shoes are worn - Replace the brake shoes
- - Excessive travel of the parking brake lever - Adjust the travel of the parking brake lever or check the routing of the parking brake cable
- - Grease has gotten on the brake shoes - Replace the brake shoes
- - Malfunction of the automatic adjustment Brake shoe clearance - Adjust the automatic brake shoe clearance adjuster
- - Parking brake cable is stuck - Adjust the operation of the parking brake cable
Noise or vibration when braking:
- - Brake shoe linings are worn - Replace the brake shoes
- - Caliper has play relative to the wheel - Tighten or replace
- - Dust cover has play relative to the brake disc - Tighten or replace
- - Brake backing plate is bent - Repair or replace
- - Brake drum or disc is unevenly worn or cracked - Replace the brake drum or disc
Squealing or vibration when braking:
- - Anti-bounce pads are worn out - Replace anti-bounce pads
- - Brake drum or disc is unevenly worn or cracked - Replace brake drum or disc
- - Brake disc is burred or rusted - Replace brake disc
- - Brake shoe contact surface is dirty or damaged - Clean or replace brake shoes
- - Upper and lower shoe return springs in drum brakes are loose or damaged, brake shoe retainers or their springs are loose or damaged - Replace damaged components
Squealing noise when brakes are not in use:
- - Brake shield is deformed with a violation of the gap with the brake drum - Replace
- - Poor mechanical treatment of the brake drum, resulting in uneven clearance between the brake shield or pads - Replace the brake drum
- - Rusted disc brakes - Clean or replace
- - In drum brakes, the upper and lower pad return springs are weak - Replace
- - Foreign objects in the brake drum - Clean the brake mechanism
- - Incorrect positioning of the brake pads in the caliper - Correctly install the brake pads
- - Incorrect fastening of the caliper to the caliper holder - Correctly install the caliper
- - Incomplete return of the brake booster, master cylinder or wheel cylinder to its original position - Replace
- - Incorrectly adjusted brake pedal or brake booster plunger - Adjust
Squeaking, clicking or rattling when the brakes are not used:
- - Stones or foreign objects have fallen into the decorative wheel cap - Remove stones or foreign objects
- - Wheel lug nuts are not tightened - Tighten lug nuts wheels
- - Disc brakes - damaged linings - Replace linings
- - Disc brakes - loose mounting bolts - Tighten mounting bolts
- - Worn, damaged, or dry wheel bearing - Lubricate or replace wheel bearing
- - Disc brakes - worn guide bushings - Replace guide bushings
- - Brake pedal or brake booster plunger not adjusted correctly - Adjust