KNORR-BREMSE® IPS90™ AND IPS100™ (INTEGRAL POWER STEERING) HYDRAULIC
POWER STEERING GEARS FOR COMMERCIAL VEHICLES
GENERAL SAFETY GUIDELINES

WARNING! PLEASE READ AND
FOLLOW THESE INSTRUCTIONS
TO AVOID PERSONAL INJURY OR DEATH:

Figure 1 - Hydraulic Power Steering Gear

Steering gears are heavy. When assembling and
disassembling the steering gears, make sure to follow
all safety protocols.
Steering fluid can get hot and reach temperatures up to
250° F (121° C). Use the appropriate PPE when servicing.
Comply with OSHA guidelines.
Avoid high-pressure hydraulic wash on steering gears
and steering sub-systems.
Unless and otherwise mentioned, use of a hammer
or heat to disassemble steering components is not
permitted.
Use manufacturer-recommended steering fluid only.
Mixing of fluids may cause internal damage to rubber
or plastic components.

When working on or around a vehicle, the following
guidelines should be observed AT ALL TIMES:
▲Park the vehicle on a level surface, apply the parking
brakes and always block the wheels. Always wear personal
protection equipment.
▲Stop the engine and remove the ignition key when working
under or around the vehicle. When working in the engine
compartment, the engine should be shut off and the ignition
key should be removed. Where circumstances require that
the engine be in operation, EXTREME CAUTION should be
used to prevent personal injury resulting from contact with
moving, rotating, leaking, heated or electrically-charged
components.
▲Do not attempt to install, remove, disassemble or
assemble a component until you have read, and thoroughly
understand, the recommended procedures. Use only the
proper tools and observe all precautions pertaining to use
of those tools.
▲If the work is being performed on the vehicle’s air brake
system, or any auxiliary pressurized air systems, make
certain to drain the air pressure from all reservoirs before
beginning ANY work on the vehicle. If the vehicle is
equipped with a Bendix® AD-IS® air dryer system, a Bendix®
DRM™ dryer reservoir module, a Bendix ® AD-9si ®, AD-HF®,
or AD-HFi™ air dryer, be sure to drain the purge reservoir.
▲Following the vehicle manufacturer’s recommended
procedures, deactivate the electrical system in a manner
that safely removes all electrical power from the vehicle.
▲Never exceed manufacturer’s recommended pressures.
▲Never connect or disconnect a hose or line containing
pressure; it may whip and/or cause hazardous airborne
dust and dirt particles. Wear eye protection. Slowly open
connections with care, and verify that no pressure is
present. Never remove a component or plug unless you are
certain all system pressure has been depleted.
▲Use only genuine Bendix ® brand replacement parts,
components and kits. Replacement hardware, tubing, hose,
fittings, wiring, etc. must be of equivalent size, type and
strength as original equipment and be designed specifically
for such applications and systems.
▲Components with stripped threads or damaged parts should
be replaced rather than repaired. Do not attempt repairs
requiring machining or welding unless specifically stated
and approved by the vehicle and component manufacturer.
▲Prior to returning the vehicle to service, make certain all
components and systems are restored to their proper
operating condition.
▲For vehicles with Automatic Traction Control (ATC), the ATC
function must be disabled (ATC indicator lamp should be
ON) prior to performing any vehicle maintenance where
one or more wheels on a drive axle are lifted off the ground
and moving.
▲The power MUST be temporarily disconnected from the
radar sensor whenever any tests USING A DYNAMOMETER
are conducted on a vehicle equipped with a Bendix ®
Wingman ® system.
▲You should consult the vehicle manufacturer's operating
and service manuals, and any related literature, in
conjunction with the Guidelines above.

1

DESCRIPTION
The Knorr-Bremse® IPS90™ and IPS100™ (Integral Power
Steering) hydraulic power steering gears are designed
for heavy duty vehicles with front axle weight ratings of
up to 16,000 lbs. It is an integral power steering gear
incorporating the mechanical and hydraulic actuation and
control components in a single cast housing which serves
as the power cylinder.

Power Steering Gear Identification
A nameplate is installed on the unit which indicates the part
number, serial number, and build date.
Data Matrix Code
Customer No.
Serial No. with
First 4 Digits

The vehicle’s steering column is coupled to the gear at
the input shaft which transmits steering effort through a
recirculating ball screw and piston nut. The piston nut is an
integral part of the power assist piston and also acts as a
steering damper. The direction and degree of power assist is
controlled by a rotary hydraulic valve which is integral to the
input shaft and supplied by an engine driven hydraulic pump.
This valve design ensures light, responsive steering while
maintaining a mechanical connection between the steering
column and the ball screw.

OPERATION
General
The hydraulic power steering gears are composed both of
mechanical steering components and hydraulic power assist
components. Actual steering is accomplished mechanically.
Effort applied at the vehicle's steering wheel results in
mechanical movement within the steering gear which causes
the vehicle to change its direction of travel. The hydraulic
power assist components function solely to reduce the
effort required to turn the vehicle's steering wheel. Loss of
hydraulic power will in no way prevent the vehicle from being
maneuvered mechanically, however, greater effort will be
required to turn the steering wheel.

Part No.
3
month
1-9,
X (10,
Y (11),
Z (12)

2

4
date

Figure 2 - Nameplate
Data Matrix Input Data:
•

+ Bendix P/N + Supplier P/N: e.g. VK123456/123V
45678

•

P + Customer P/N: e.g. P12-34567-000

•

+ Date + Serial Number: e.g. S0324123 (example for
S
2020/03/24 No. 123)

Arranging input data in a row and each data is delimited by
# mark: VK123456/123-45678#P12-34567-00#S0324123
Description

IPS90

IPS100

Steering ratio

18.8 - 20.8

18.7 - 20.2

Turning angle output
shaft w/o poppets

100° +4°

96° +4°

Adjustable turning
angle output shaft

30° - 50°

34° - 48°

Output torque at 185
bar 90% efficiency

4523 - 5000 N•m /
3336 - 3688 ft-lbs

6174 - 6670 N•m /
4554 -4920 ft-lb

Maximum working
temp

121° C / 249.8° F

121° C / 249.8° F

Minimum flow rate

8 l/min

11 I/min

Normal flow rate

16 I/min

16 I/min

Max. pressure

185 bar +7/-3 bar

185 bar +7/-3 bar

Table 1 - Technical Data

2

0
year
2020

Dual Steering Gear System
Two or more steering gears (“master” and “slave” units) are
sometimes used where front axle weights exceed 16,000
lbs. Dual steering gear systems balance the steering gear
output across two or more steering arms and conserve space
under the hood.
Pressure from the master gear on the vehicle’s left side
powers the secondary, or slave unit, on the vehicle’s right
side. Hydraulic pressure and flow move the slave gear in
the opposite direction of the master gear. Another difference
between the two units is that hydraulic relief plungers are not
used in the slave gear. Master gear relief plungers will relieve
hydraulic pressure for both gears when properly adjusted.
See Figure 6 for an exploded view of a slave gear application.
The dual system is mechanically linked to the front-end
components by a drag link and steer arm on the right-hand
spindle on the axle. Only hydraulic connections with no
physical mechanical components exist between the master
and slave units.

Figure 4 - Hydraulic Power Steering Gear - Exploded
View

PREVENTIVE MAINTENANCE
Power Steering Oil

IMPORTANT

Secondary
(Slave) Gear

The vehicle manufacturer's recommendations is that an
approved oil be used to ensure proper operation of the
power steering unit.
Return from Master
to Reservoir
Steering Gear
Inlet Line

Reservoir for
Pump
Pump

Main Steering
Gear

Steering
Column

Once an oil type is in use, it should never be mixed with
any other type. If it should become necessary to change
types of oil, the entire system must be drained following the
procedure below.
Draining and Filling the System
1. L
ift the front axle sufficiently to raise the wheels clear
of the ground.
2. D
isconnect the return line at the valve body outlet
port. Turn the steering wheel to the left as far as it will
go. Run the engine for up to ten (10) seconds until
the oil is drained from the reservoir and pump. Switch
off the engine and turn the steering wheel backwards
and forwards from full lock to full lock until all the oil is
drained out.
3. C
lean the outside of the reservoir. Remove the old filter
element. Replace with the new filter.
4. Connect the return line at the valve body outlet port
and tighten the nut with the torque to be specified in the
maker's manual.
5. Fill the reservoir full of oil.

Figure 3 - Standard Slave System

6. Turn the engine over with the starter motor. (Must be
done in a manner that the engine does not start.) Add
oil as the level drops to avoid air being drawn into the
system.
7. When the oil level reaches the full mark on the reservoir,
start the engine and turn the steering wheel slowly from
side to side until air bubbles cease to appear in the
reservoir. Refill the reservoir to the full mark.
8. The oil level should be checked every 2,000 miles.
3

Change Intervals

Bill of Material for Service Kits

It is recommended that the oil be changed at 40,000-mile
intervals and at the time of rebuild. Beyond its function as
the medium for transmitting power, the oil also serves to
lubricate and dissipate heat. Carefully clean, inspect, and
replace if necessary, all filter elements in the pump system.

In order to identify the right service kit to solve a certain
issue mentioned in the troubleshooting guide, the steering
gear specific service kit specification needs to be viewed.

The gear lash between the piston teeth and sector gear
should not require attention in normal service, however, a
provision for an adjustment is provided.
Output Shaft Boot Seal
Inspect the integrity of the output shaft boot seal located
between the pitman arm and the housing. This component
prevents contamination from entering the output shaft
bearing and retains grease on the bearing and output shaft
to prevent corrosion. If deterioration or leakage is detected,
it should be replaced.

For direct personal technical support, call the Bendix Tech
Team at 1-800-AIR-BRAKE (1-800-247-2725), Monday
through Thursday, 8:00 a.m. to 6:00 p.m. ET, and Friday,
8:00 a.m. to 5:00 p.m. ET. The Tech Team is also available
by email at techteam@bendix.com.
In general, there are four (4) different kinds of service kits
available:
A. Full seal kit that contains all the internal and external
steering gear seals.
B. Poppet kit that contains all the parts to change and reset
the poppets.
C. Pitman arm connection kit that contains the parts to
disassemble and reassemble a pitman arm.
D. Input shaft seal kit that contains the seals around the
input shaft.

(140) Dirt and Water Seal

(150) Poppet
Cartridge

(120) Backup Ring

(1130) Jam Nut

(110) Oil Seal

(157) O-Ring

(1120) Split Lock
Washer

(156) O-Ring
(1110) Flat Washer

(840) Oil Seal

(990) Dust Cap
3x (272) Seal Ring
(590) O-Ring
3x (271) O-Ring
(830) Backup Ring
(640) Seal Ring
(273) O-Ring

(630) O-Ring
(280) O-Ring

(470) Input
Shaft Seal

(290) O-Ring
(942) Plunger Assembly
(947) O-Ring

(980) Dust Cap

(946) Plug

Figure 5 - Service Kit Components Exploded View

4

(860) O-Ring

The following list gives an overview of all the steering gear
seals:

ATTENTION
Please notice that the slave gear application is missing
some of the seals that are part of the master gear. This
instruction is created to describe the replacement of
all the master gear seals. When servicing a slave gear,
please skip the steps referring to seals that are only part
of the master gear.
Number

Part Name

QTY Master
Gear

QTY Slave
Gear

110

PACKING-Y

1

1

120

RING-BACK UP

1

1

140

OIL SEAL

1

1

271

O-RING

3

-

272

SEAL-RING

3

-

273

O-RING

1

-

280

O-RING

1

1

290

O-RING

2

-

470

OIL SEAL

1

-

630

O-RING

1

1

640

SEAL-RING