Kia Sephia/Shuma/Spectra

since 1995 of release

Repair and car operation

KIA of Sefia / Noise/range
+ 2. Engine
+ 3. Greasing system
+ 4. Cooling system
+ 5. Power supply system and release
+ 6. Fuel system
+ 7. Ignition system
+ 8. Coupling
+ 9. Mechanical transmission
+ 10. Automatic transmission
+ 11. Axes and power shafts
+ 12. Steering
+ 13. Wheels and tires
- 14. Brake system
   14.1. Specifications
   14.2. Pumping of hydraulic system of a drive of brakes
   14.3. Check of brake tubes and hoses
   14.4. Replacement of brake hoses
   14.5. Height of installation of a pedal of a brake
   14.6. Free wheeling of a pedal of a brake
   14.7. Distance of a pedal of a brake from a floor
   14.8. Check of the vacuum amplifier of brakes
   14.9. Parking brake
   14.10. Brake pedal
   14.11. Main brake cylinder
   14.12. Vacuum amplifier of brakes
   14.13. Replacement of forward brake shoes
   14.14. Replacement of brake shoes on back drum-type brakes
   14.15. Replacement of brake shoes on back disk brakes
   14.16. Parking brake
   14.17. Block of hydraulic management (HCU)
   14.18. Forward sensor of frequency of rotation of a wheel
   14.19. Back sensor of frequency of rotation of a wheel
   14.20. Gear rotor of the sensor of frequency of rotation of a wheel
   14.21. Repair of the working brake cylinder
   14.22. Main survey
   14.23. Check of functionality
   14.24. List of codes of malfunctions of brake system
+ 15. Suspension bracket
+ 16. Body
+ 17. Central air
+ 18. Electric equipment


14. Brake system


On cars the working brake system with a hydraulic drive is used.

The system works as follows:

   – the pedal of a brake is connected with the main brake cylinder;
   – when the pedal is pressed, liquid under pressure from the main brake cylinder on metal tubes and flexible hoses is transferred to lobbies and back brake mechanisms;
   – working brake cylinders represent hydraulic modulators which transform the pressure of liquid created in the main brake cylinder in moving by an element of the brake mechanism;
   – lobbies and back pistons of a support of a brake move, and at the expense of a friction about brake disks and drums provide demanded delay of the car;
   – at an otpuskaniye of a pedal of a brake, pressure in system decreases. Brake shoes and pistons come back to a neutral or starting position and braking stops.

At reduction of level of brake liquid, the sensor of level of liquid in the main brake cylinder includes a control lamp in combinations of devices. If the control lamp burns, first of all check that the parking brake is released, as the lamp indicates the lowered level of liquid and the tightened parking brake.

Arrangement of elements of brake system on the car

1–brake tube;
2–brake pedal;
3–main brake cylinder;
4–vacuum amplifier of brakes;
5–forward disk brake mechanism;
7–back drum-type brake mechanism (CBS);
8–parking brake;
9–cable of the parking brake;
10-lever of the parking brake;
11-tube of the highway of a high pressure of brake system;
12-back disk brake mechanism (ABS)

Anti-blocking system of brakes (ABS)

The anti-blocking system of brakes is intended for an exception of blocking of wheels at intensive braking.

Main ABS functions:

   – reduction of a brake way at the expense of an exception of blocking of wheels at intensive braking;
   – improvements of stability of driving in the course of braking.

The anti-blocking system of brakes works at information basis from four sensors transferred to the ABS block. The system operates each wheel separately and reduces pressure of liquid in that wheel brake mechanism which wheel starts to be blocked.

Arrangement of elements of anti-blocking system of brakes (ABS) on the car

1–block of hydraulic management (HCU);
2–rotor of the sensor of frequency of rotation of a wheel;
3–sensor of frequency of rotation of a wheel;
4–association pipelines

Under normal conditions, the standard brake system carries out braking till blocking of the wheel found by the ABS control unit. During usual braking inlet valves usually open, and final valves are usually closed.

When the ABS control unit finds wheel blocking, it operates each valve for increase or pressure reduction.

The ABS control unit defines frequency of rotation and norm of delay of each wheel on the basis of information from sensors of frequency of rotation of a wheel. When braking frequency of rotation of a wheel decreases, and the ABS block defines a difference between speed of the car and frequency of rotation of a wheel. If delay of some wheels exceeds expected value, the ABS block defines the beginning of blocking and opens the corresponding electromagnetic valves to reduce pressure of brake liquid.

Thus frequency of rotation of a wheel increases, and the electromagnetic valve of dumping of pressure is closed and there is an increase in pressure of brake liquid in the working brake cylinder of the corresponding wheel.

ABS control unit

The ABS control unit carries out the following functions:

   – ABS operates;
   – calculates speed of the car;
   – carries out system self-diagnostics: codes of malfunctions with self-diagnostic and safety functions are brought in memory by two separated microprocessors.

The ABS control unit continuously checks blocking of each wheel and operates each valve to regulate pressure of brake liquid if it is required. The ABS control unit also checks that components work properly, and switches off ABS, at detection of failures. Then the brake system works as standard brake system.

Sensor of frequency of rotation

The sensor of frequency of rotation finds rotation of a wheel and consists of a constant magnet and the coil. Sensors of forward wheels receive information from the gear rotors located on power shafts.
When passing teeths of a rotor about the sensor, the magnetic field of the sensor therefore the tension impulse is developed changes. This tension is proportional to frequency of rotation of a wheel and can be measured.

Control lamp of ABS

The control lamp of ABS located in a combination of devices lights up for 2 seconds after ignition inclusion.

If the control lamp of ABS does not die away in 2 seconds after inclusion of ignition or lights up periodically, means in ABS there are violations.

In the presence of violations the brake system works as standard brake system.

Block of hydraulic management (HCU)

The block of hydraulic management (HCU) consists of the pump with an electric motor and the block of valves to operate pressure of ABS.

The sensor is located in the electric motor of the pump and transmits a target signal to the ABS block which defines operability of the pump.

Diameter of a forward opening of a pipe of supply of brake liquid:
Forward left and back right brakes: 12 mm
Forward right and back left brakes: 10 mm

The pump with two contours provides demanded pressure, and the block of valves distributes the pressure transferred to wheel brake mechanisms.

ABS self-diagnostics

The ABS control unit starts to carry out self-diagnostic functions after ignition inclusion. The ABS control unit finds malfunction for each contour, and a component, comparing a system condition to a limited set of conditions in the ABS control unit. The ABS control unit stores a code of malfunction and then deduces on the diagnostic device in the form of the codes designated by four figures.

Check of codes of self-diagnostics

1. Turn a key in the ignition lock in the situation OFF and connect the diagnostic device to the diagnostic socket.
2. Turn a key in the ignition lock in the situation ON and on the device set model of the car and model of the diagnostic device.
3. Choose the checked parameter, after block initialization.
4. Press check of codes No. 1 and find out, whether malfunction is written down.  


Malfunction code – number with four figures which appears continuously while the code of malfunction is not erased by the diagnostic device.

5. According to the list of codes of malfunction, reveal a faulty element and restore its working capacity.
6. After deleting of codes of malfunction from memory of the ABS control unit choose inspection point No. 4.

Precautions before carrying out repair

1. For prevention of damage of elements of brake system before carrying out repair or diagnostics satisfy the following conditions:

   – switch off ignition and disconnect each component of brake system;
   – components which are not maintainable, replace as knot;
   – when using electric welding disconnect each component of brake system.

Brake liquid dissolves paint, plastic and isolation of wires therefore at casual hit of liquid on a paint and varnish covering of the car or its components, wash out them a large amount of water.