power steering SSANGYONG NEW ACTYON SPORTS 2012 User Guide

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2) Operation of ESP System
The ESP (Electronic Stability Program) has been developed to help a driver avoid danger of losing
control of the vehicle stability due to understeer or oversteer during cornering. The yaw rate
sensor, lateral sensor and longitudinal sensor in the sensor cluster and the steering wheel angle
sensor under the steering column detect the vehicle conditions when the inner or outer wheels are
spinning during oversteer, understeer or cornering. The ESP ECU controls against oversteer or
understeer during cornering by controlling the vehicle stability using input values from these
sensors and applying the braking force to the corresponding wheels independently. The system
also controls the engine power right before the wheel spin synchronized with the ASR function to
decelerate the vehicle automatically in order to maintain the vehicle stable during cornering.
(1) Under steering
What is understeering? ▶
Understeer is a term for a condition in which the steering wheel is steered to a certain angle during
driving and the front tires slip toward the reverse direction of the desired direction. Generally,
vehicles are designed to have understeer. It is because that the vehicle can return back to inside of
cornering line when the steering wheel is steered toward the inside even when the front wheels are
slipped outward.
As the centrifugal force increases, the tires can easily lose the traction and the vehicle tends to slip
outward when the curve angle gets bigger and the speed increases.

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5) ARP (Active Roll-Over Protection
The ARP (Active Roll-over Protection) system is a safety assistant device that minimizes, by
controlling brakes and the engine, the physical tendency of the vehicle rollover during sharp lane
changes or U-turns. For the system, software is added to the existing ESP system and no
additional device or switch is needed. One must note that the ARP system, just as general
assistant devices including the ABS, is only a safety assistant device using the ESP system and its
function is useless when the situation overcomes the physical power. Following picture shows
how the ARP compensates the vehicle position by varying each wheel's braking power to
overcome the physical tendency of the vehicle rollover during sharp turns.
Lateral sensor
(In sensor cluster)
Vehicle speedBrake force
Radius
The vehicle driving condition is controlled by the internally programmed logic according to the
input signals from wheel speed sensor, steering angle sensor and lateral sensor.
During the ARP operation, vehicle safety (rollover prevention) takes the first priority and thus,
stronger engine control is in effect. Consequently, the vehicle speed decreases rapidly, so the
driver must take caution for the vehicle may drift away from the lane.

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2) Steering Gear Linkage
Linkage assembly - gear & operation
ball joint
Bolt (100~130 Nm)
Nut (100~130 Nm)
Bolt (100~130 Nm)
Nut (100~130 Nm)
Bolt (100~130 Nm) 1.
2.
3.
4.
5.
6.Pin
Nut
End assembly - tie rod
Boot kit - power steering gear box
Clamp - mounting
Rubber - mounting 7.
8.
9.
10.
14.
15.

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Oil Change ▶
Open the power fluid reservoir cap and
drain the fluid completely with oil suction
device. To make it easy, turn the steering
wheel to its both ends several times.
Fill up the specified fluid into fluid reservoir
and bleed air from the steering system. 1.
2. Oil Level Check ▶
Place the vehicle on a level ground and
start the engine and let it run at idle speed.
Turn the steering wheel several times so
that the oil temperature reaches to normal
operating level (75~85˚C).
Place the steering wheel at straight ahead
direction.
Check the oil level in the power steering oil
reservoir. Adjust the oil level between MAX
and MIN. 1.
2.
3.
4.
If the difference between two
measurements is below 5 mm and the level
is between MAX and MIN level, it's normal.
If it is over 5 mm, bleed air from the
system. Check the fluid level on a level ground with
the engine turned off. The fluid level should
be between the MIN and MAX marks on the
reservoir cap gauge.
below 5 mm
Engine idling Engine running
Oil typeATF Dexron II or III
Capacityapprox. 1ℓ (including
reservoir)

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Air Bleeding ▶
Lift up the vehicle very carefully.
Turn the steering wheel to its both ends
several times and add the oil up to MAX
line in the steering oil reservoir.
Periodically crank the starting motor and
turn the steering wheel to its both ends
without any interruption.
Check the oil level again. If the oil level is
fluctuated, repeat the procedures from
step 3 to step 5.
Start the engine.
Turn the steering wheel to its both ends
until any bubble can be found in the
steering oil reservoir.
Perform the test drive and check the
steering wheel for normal operation and
noise.
If the oil level abruptly goes up, bleed the
air from the system again. 1.
2.
3.
4.
5.
6.
7.
8.
The air bleeding should be done after
servicing the power steering system and when
the difference between two measurements
(cooled and normal temperature) is
prominent.
Max
Min
Normal Abnormal
If the air bleeding is not properly
performed, the life span of the power
steering pump may be shortened. -

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Oil Pump Pressure Check ▶
Unscrew the pressure line fitting in power
steering pump.
Install the pressure gauge between the
power steering pump and the power
steering oil pressure line.
Place the shift lever to neutral position.
Apply the parking brake.
Open the valve in pressure gauge. Start
the engine and let it run at idle speed.
Turn the steering wheel several times so
that the oil temperature reaches to normal
operating level. 1.
2.
3.
4.
5.
Before checking the pressure, check the oil
level and belt tension. Prepare the empty
container to collect the spilled oil during the
service. Check the oil pump pressure to locate any
defect in oil pump.
Fully close the valve in pressure gauge and
measure the oil pressure. 6.
Relief pressure
90 ± 3 bar
Oil pump
Steering gear box
To prevent internal damage, do not close
the gauge valve over 10 seconds.
Keep the oil temperature at proper range. -
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Measure the oil pressure with the gauge
valve fully open. 7.
Pressure at no load
3 to 5 bar
If the pump pressure is in specified range,
the pump is normal. If not, replace the
power steering pump 8.
Turn the steering wheel righ or left until it
stops with the engine idling ans valve fully
open. 9.
Oil pressure78 to 83 bar
To prevent the internal damage, do not
close the gauge valve for over 10
seconds.
Keep the oil temperature at proper range. -
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1. SYSTEM DESCRIPTION
The power steering has been designed to make the wheel move more easily than in a manual
steering system. The hydraulic power assists the process utilizing hydraulic fluid. The fluid
increases pressure in the power steering pump and aids the movement of the steering
mechanism. The power steering system consists of pump, oil reservoir, rack and gear box. The
power steering pump is a vane type and delivers hydraulic pressure to operate the power steering
system. The pressure relief valve in the pump controls the discharging pressure. The rotary valve
in the rack and the pinion gear directs the oil from the power steering pump to one side of the
rack piston. The integrated rack piston converts the hydraulic pressure to linear movement. The
operating force of the rack moves the wheels through the tie rod, the tie rod end and the steering
knuckle. Even though the hydraulic pressure cannot be generated, a driver can steer the vehicle
without power assist but it needs very high steering force. In this case, the operating force of the
steering wheel is conveyed to the pinion, and the movement of the pinion moves the rack through
the pinion gear combined to the rack gear.

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2. SYSTEM LAYOUT
The steering pump is driven by the engine power through a belt. This pump circulates the power
steering oil from the reservoir -> steering pump -> oil supply pipe -> steering gear box -> oil
return pipe -> reservoir to perform steering operations
Steering pump Steering return pipe Steering cylinder
Return line
High pressure line
Return hose & tube
Steering pump &
reservoir
High pressure hose
Linkage gear box Steering wheel
Lower shaft Column & shaft