DAEWOO LACETTI 2004 Service Repair Manual

6C – 24IPOWER STEERING GEAR
DAEWOO V–121 BL4
Assembly Procedure
Notice : Coat all the seals with power steering fluid to en-
sure proper sealing.
1. Install the rack, the bulkhead inner cylinder and the
bulkhead inner cylinder retaining ring.
Notice : To prevent the inner tie rods from loosening, use
Loctite® 242 (or equivalent) on both inner tie rod connec-
tions to secure them to the rack shaft.
Important : The right and left inner tie rods are unequal
in length. Be sure to install the correct inner tie rod on the
proper side of the power steering gear.
2. Firmly seat the inner tie rods against the rack and
tighten both ends simultaneously.
Tighten
Tighten the inner tie rods to 100 NSm (74 lb–ft).
3. Push the plastic retainer back onto the connection
between the inner tie rod and the power steering
gear rack.
4. Install the dust boot.

POWER STEERING GEAR 6C – 25
DAEWOO V–121 BL4
5. Install the cylinder end dust boot retaining clamps
with the installer KM–J–22610.
6. Install the tie rod end boot retaining clamps.
7. Reposition the adjusting nut to the marks on the
inner tie rod and install the outer tie rod by twisting
it onto the inner tie rod.
8. Perform a front toe adjustment. Refer to Section
2B, Wheel Alignment.
9. Tighten the adjusting nut.
Tighten
Tighten the outer tie rod adjusting nut to 64 NSm (47
lb–ft).
10. Install the rack bearing assembly into the rack and
pinion steering assembly. Refer to ”Rack Bearing”
in this section.
11. Install the valve and pinion assembly into the rack
and pinion steering assembly. Refer to ”Valve and
Pinion” in this section.
12. Install the rack and pinion steering assembly into
the vehicle. Refer to ”Rack and Pinion Assembly”
in this section.

6C – 26IPOWER STEERING GEAR
DAEWOO V–121 BL4
STUB SHAFT SEALS AND UPPER
AND LOWER BEARING
Disassembly Procedure
1. Remove the rack and pinion steering assembly
from the vehicle. Refer to ”Rack and Pinion Assem-
bly” in this section.
2. Remove the dust cover from the lower end of the
housing.
Notice : If the stub shaft is not held, damage to the pinion
teeth will occur.
3. While holding the stub shaft with a wrench, remove
the locknut from the pinion.
4. With the gear centered, mark the location of the
stub shaft notch on the housing to aid in properly
installing the valve and pinion assembly.
5. Remove the stub shaft retaining ring and, using an
arbor press, press on the threaded end of the pin-
ion until it is possible to remove the pinion and
valve assembly from the housing.

POWER STEERING GEAR 6C – 27
DAEWOO V–121 BL4
6. Remove the stub shaft dust seal the stub shaft
bearing annulus assembly and the valve assembly
from the housing. Discard the stub shaft dust seal.
7. Remove the lower valve assembly bearing and the
bushing.
8. Remove the lower bearing assembly retaining ring
and press the lower bearing assembly from the low-
er end of the housing.
Assembly Procedure
Notice : Coat all the seals with power steering fluid to en-
sure proper sealing.
1. Install the lower bearing assembly and the lower
bearing assembly retaining ring into the lower end
of the housing.

6C – 28IPOWER STEERING GEAR
DAEWOO V–121 BL4
2. Install the lower valve assembly bearing and the
bushing.
3. Center the rack in the housing.
4. Install the the valve assembly, the stub shaft bear-
ing annulus assembly and a new stub shaft dust
seal into the housing.
Important : When the valve and pinion assembly is fully
seated in the housing, be sure that the notch in the stub
shaft and the mark on the housing line up.
Notice : If the stub shaft is not held, damage to the pinion
teeth will occur.
5. While holding the stub shaft, install the locknut onto
the pinion shaft.
Tighten
Tighten the pinion locknut to 30 NSm (22 lb–ft).
6. Replace the dust cover onto the housing.
7. Install the rack and pinion steering assembly. Refer
to ”Rack and Pinion Assembly” in this section.

POWER STEERING GEAR 6C – 29
DAEWOO V–121 BL4
RACK BEARING
Tools Required
J–42459 Rack Guide Spring Cap Wrench
Disassembly Procedure
1. Remove the rack and pinion steering assembly
from the vehicle. Refer to ”Rack and Pinion Assem-
bly” in this section.
2. Remove the adjuster plug locknut from the adjuster
plug, and remove the adjuster plug from the hous-
ing with the rack guide spring cap wrench J–42459,
or with a 19 mm allen wrench.
3. Remove the adjuster spring and the rack bearing.
Assembly Procedure
1. Coat the rack bearing, the adjuster spring and the
adjuster plug with lithium–based grease and install
them into the housing.
2. With the rack centered, turn the adjuster plug clock-
wise until a torque of 7 NSm (62 lb–in) is obtained,
then back it off by 30 to 40 degrees. Check the pin-
ion torque. Maximum pinion preloaded torque is 1
NSm (9 lb–in).
3. Thread the locknut on the adjuster plug and tighten
it.
Tighten
Tighten the adjuster plug locknut to 75 NSm (56 lb–ft)
while holding the adjuster plug stationary with the rack
guide spring cap wrench J–42459 or with a 19 mm al-
len wrench.
4. Install the rack and pinion assembly. Refer to ”Rack
and Pinion Assembly” in this section.

6C – 30IPOWER STEERING GEAR
DAEWOO V–121 BL4
RACK BEARING PRELOAD
ADJUSTMENT
Adjustment Procedure
1. Raise and suitably support the vehicle.
2. Center the steering wheel.
3. Remove the power steering gear. Refer to ”Rack
and Pinion Assembly” in this section.
4. Loosen the locknut and turn the adjuster plug clock-
wise until a torque of 7 NSm (62 lb–in) is obtained,
then loosen it by 30 to 40 degrees. Check the pin-
ion torque. Maximum pinion preloaded torque is 1
NSm (9 lb–in).
5. Tighten the locknut on the adjuster plug while hold-
ing the adjuster plug stationary.
6. Install the power steering gear. Refer to ”Rack and
Pinion Assembly” in this section.
7. Be sure to check the returnability of the steering
wheel to center position after adjustment.
Tighten
Tighten the adjuster plug locknut to 75 NSm (56 lb–ft).
VALVE AND PINION
Disassembly Procedure
1. Remove the rack and pinion steering assembly
from the vehicle. Refer to ”Rack and Pinion Assem-
bly” in this section.
2. Remove the dust cover from the lower end of the
housing.
Notice : If the stub shaft is not held, damage to the pinion
teeth will occur.
3. While holding the stub shaft, remove the locknut
from the pinion.

POWER STEERING GEAR 6C – 31
DAEWOO V–121 BL4
4. With the gear centered, mark the location of the
stub shaft notch on the housing to aid in properly
installing the pinion and valve assembly.
5. Remove the upper housing retaining ring and, using
an arbor press, press on the threaded end of the
pinion until it is possible to remove the valve and
pinion assembly from the housing.
6. Remove the stub shaft dust seal, the stub shaft
bearing annulus assembly and the valve and pinion
assembly from the housing.
7. Inspect the valve body rings for wear or damage.
Replace the valve body rings as needed. Coat the
rings with power steering fluid before installation.
8. Remove the lower pinion valve seal and bushing.
Discard the seal.

6C – 32IPOWER STEERING GEAR
DAEWOO V–121 BL4
Assembly Procedure
Notice : Coat all of the seals and bushings with power
steering fluid to ensure proper sealing.
1. Install the bushing and a new lower pinion valve
seal.
Important : When the valve and pinion assembly is fully
seated in the housing, be sure the notch in the stub shaft
and the mark on the housing line up. If this is not done the
vehicle will not pass the straight–ahead check and will
have poor steering performance.
2. Install the valve and pinion assembly, the stub shaft
bearing annulus assembly and the stub shaft dust
seal.
Notice : If the stub shaft is not held, damage to the pinion
teeth will occur.
3. While holding the stub shaft, tighten the locknut
onto the pinion shaft.
Tighten
Tighten the pinion locknut to 30 NSm (22 lb–ft).
4. Replace the dust cover onto the housing.
5. Install the rack and pinion steering assembly. Refer
to ”Rack and Pinion Assembly” in this section.
6. Perform the straight–ahead check. Refer to
”Straight–Ahead Check” in this section.

POWER STEERING GEAR 6C – 33
DAEWOO V–121 BL4
GENERAL DESCRIPTION
AND SYSTEM OPERATION
POWER RACK AND PINION
The power rack and pinion steering system has a rotary
control valve that directs hydraulic fluid coming from the
hydraulic pump to one side or the other side of the rack pis-
ton. The integral rack piston is attached to the rack. The
rack piston converts hydraulic pressure to a linear force
that moves the rack left or right. That force is then trans-
mitted through the tie rods to the steering knuckles, which
turn the wheels.
If power rack and pinion steering is not available, manual
rack and pinion control is used; however, with this system,
more steering effort is required. The movement of the
steering wheel is transferred to the pinion. The rotary
movement of the pinion is then transferred through the pin-
ion threads, which mesh with teeth on the rack, thereby
causing the rack to move in a linear direction.
A vane–type of hydraulic pump provides hydraulic pres-
sure for both steering systems.
SPEED SENSITIVE POWER
STEERING SYSTEM
The speed sensitive power steering (SSPS) system varies
the driver effort required to steer as the vehicle speed
changes. At low speeds, the system provides maximum
power assist for easy turning and parking maneuvers. At
higher speeds, the steering power is reduced to provide
the driver with firmer steering and directional stability. The
SSPS system accomplishes this by reducing the amount
of power steering fluid flow from the power steering pump
to the power steering gear as the vehicle speed increases.
When the vehicle is stationary, the SSPS system provides
maximum fluid flow to the steering gear. As the vehicle
speed increases, the fluid flow to the steering gear is de-
creased.
Control Module
The SSPS control module processes the vehicle speed in-
formation from the engine control module (ECM) and uses
the steering wheel rotation sensor to provide a control sig-
nal to the electronic variable orifice (EVO) actuator located
on the power steering pump.
Electronic Variable Orifice (EVO) Actuator
The electronic variable orifice (EVO) actuator is located on
the power steering pump and contains a solenoid– oper-
ated pintle valve. Fluid leaving the pump passes through
an orifice in the actuator tip. When the EVO actuator is
powered by the SSPS control module, the pintle moves
into the orifice and reduces the power steering fluid flow.As the vehicle speed increases, current from the SSPS
control module increases, and the pintle blocks more and
more of the orifice.
Steering Wheel Rotation Sensor
The steering wheel rotation sensor is located at the end of
the steering column housing and is used to send a signal
to the controller when abrupt or evasive steering maneu-
vers are needed.
Power Steering Pressure Hose
SSPS vehicles have a specific pressure hose assembly
which includes an in–line check valve in the rack and pin-
ion assembly. This reduces the amount of steering wheel
”kick” when driving over irregular road surfaces while oper-
ating at speeds with reduced flow rate and pressure.
Power Rack and Pinion
Except for differences in valve machining, the design of
the SSPS power rack and pinion assembly is the same as
for the a non–SSPS system. The steering wheel move-
ment is transferred to the pinion via the intermediate shaft.
The pinion moves the rack left or right through meshing the
pinion and the rack teeth. The force is then transmitted
through the tie rods and steering knuckle to steer the
wheels.
The power rack and pinion steering system has a rotary
control valve which directs the hydraulic fluid from the
power steering pump to one side or the other side of the
rack piston. The piston is attached to the rack and uses hy-
draulic pressure to move the rack left or right. The rotary
control valve regulates the degree of assist by responding
to the driver’s torque input.
If hydraulic assist is not available, manual control is main-
tained. However, under this condition, more steering effort
is required.
Power Steering Pump
The standard vane–type pump, which provides hydraulic
pressure for the system, incorporates a special discharge
fitting to hold the EVO actuator.
System Operation
System operation originates with input from the vehicle
speed sensor via the engine control module to the SSPS
control module. The SSPS control module sends a signal
to the SSPS actuator to vary the rate of fluid flow output
by the power steering pump.
Circuit Operation
The SSPS system uses inputs from the speed sensor and
steering wheel rotation sensor to the SSPS controller to
determine the desired amount of power steering assist.
The SSPS control module constantly compares the
amount of current flowing through the EVO actuator to the
desired current it has calculated. The EVO actuator has a
pintle that moves in and out of an orifice, regulating power