Bendix® GSAT® (Global Scalable Air Treatment) Core Module Replacement Kit
for Daimler® Truck North America (DTNA)
KIT COMPONENTS
See Figure 1. The following component is in the Bendix®
GSAT® (Global Scalable Air Treatment) core module kit for
Daimler® Truck North America (DTNA):
Item No.

Component

Quantity

1

L2 Core Module 2X EPB

1

Bendix Kit Part Number: K282589SC

Electrical
Connector

Figure 1 – GSAT Core Module Kit

VEHICLE PREPARATION
1. Park the vehicle on a level surface and chock the wheels.
2. Turn the ignition switch OFF.
3. Drain all reservoirs to 0 psi (0 kpa).
4. Disable electrical power to the vehicle per the Original
Equipment Manufacturer (OEM) instructions.

Always depressurize the air dryer and all other
reservoirs on the vehicle to 0 psi (0 kpa) before servicing
the air dryer. Failure to drain the air pressure from the
air dryers and all other reservoirs may result in property
damage, serious injuries, and/or death.

GENERAL SAFETY GUIDELINES

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

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
IMPORTANT
Do not install the core module included in this kit if it
does not match the one being removed.
This kit is used to replace the Bendix® GSAT® (Global Scalable
Air Treatment) core module. This is not a retrofit kit. This
kit cannot be installed on vehicles that do not have an
existing GSAT system. Be sure to verify the core module
included in this kit is identical to the core module you
are replacing. Ensure both core modules have the same
number of exhaust silencers and the same port and mounting
configurations in the same locations.

When replacing the core module assembly, it is mandatory
that the air dryer cartridge be replaced at the same time.
For replacement kit part numbers and instructions, refer
to S-1704, Bendix® GSAT® (Global Scalable Air Treatment)
Air Dryer Cartridge Kit for Daimler® Truck North America
(DTNA), on B2Bendix.com.

Air Connection
Port ID

Function/
Connection

Port Size
ISO 4039-2

Maximum
Torque

13

Energy Inlet from
Supply Tank

M22x1.5

44 ft-lb
(60 N•m)

21

Energy Outlet
Service Brake Rear
Axle

M22x1.5

44 ft-lb
(60 N•m)

22

Energy Outlet
Service Brake
Front Axle

M22x1.5

44 ft-lb
(60 N•m)

23

Energy Outlet
Transmission

M22x1.5

44 ft-lb
(60 N•m)

26

Energy Outlet
Auxiliary Devices

M22x1.5

44 ft-lb
(60 N•m)

26.1

Energy Outlet
Auxiliary Devices

M16x1.5

33 ft-lb
(45 N•m)

27

Energy Outlet Air
Suspension

M22x1.5

44 ft-lb
(60 N•m)

43

Inlet Port for
External Release
EPB Tractor

M16x1.5

33 ft-lb
(45 N•m)

M16x1.5

33 ft-lb
(45 N•m)

46

Control Outlet for
Air Dryer Pressure
Regulator/TCOV
Control for CFL

M16x1.5

33 ft-lb
(45 N•m)

51

Control Outlet for
Air Compressor

M16x1.5

33 ft-lb
(45 N•m)

52

Energy Outlet
for Truck Spring
Brakes 1

M22x1.5

44 ft-lb
(60 N•m)

53

Energy Outlet
for Truck Spring
Brakes 2

M22x1.5

44 ft-lb
(60 N•m)

53.1

Energy Outlet
for Truck Spring
Brakes 3

M22x1.5

44 ft-lb
(60 N•m)

M22x1.5

44 ft-lb
(60 N•m)

44

Available only for
2xEPB Applications

55

Figure 2 – Core Module Connections

2

Inlet Port for
External Release
EPB Trailer

Energy Outlet for
Trailer Supply Line
Available only for
2xEPB Applications

56

Energy Outlet
for Air Dryer
Regeneration

M16x1.5

33 ft-lb
(45 N•m)

M12 Mounting

Core Module to
Vehicle Mounting

M12x1.5

55 ft-lb
(75 N•m)

Table 1 –Core Module Connections

DISASSEMBLY

ASSEMBLY

1. Identify and mark all connections on the air dryer for
ease of reinstallation.

1. Secure the core module to the vehicle using the six (6) M12
mounting bolts that were removed during disassembly.
Torque all bolts to 55 ft-lbs (75 N•m).

2. Disconnect all air lines and fittings from the core module.
3. Disconnect the electrical connector from the core module.
4. Remove and retain the six (6) M12 mounting bolts that
secure the core module to the vehicle.
5. Remove the core module from the vehicle.
6. Remove and replace the air dryer cartridge per S-1704,
Bendix® GSAT® (Global Scalable Air Treatment) Air Dryer
Cartridge Kit for Daimler® Truck North America (DTNA),
on B2Bendix.com.
NOTE: After replacing the air dryer cartridge, you will not be
able to reset the cartridge lifetime wear and wetness until
the new core module is installed.

Cleaning and Inspection
1. Before installing the replacement part, inspect it for
physical damage to the body casting and take note of
broken or missing parts.

2. Reinstall all air lines and fittings to the new core module
as marked during the disassembly process.
3. Reattach the electrical harness to the core module
connector interface; lock it into place with the integrated
locking tab.
4. Resore electrical power to the vehicle per the OEM's
instructions.
5. Before placing the vehicle in service, the GSAT system
must be programmed to the OEM configuration to properly
function. Use the DTNA diagnostic tool to update the
configuration software per the Vehicle Identification
Number (VIN).
6. Because of the replacement air dryer cartridge, the
cartridge lifetime wear and wetness content will need
to be reset. Use ACom Diagnostic Software, or a DTNA
diagnostic tool, to initiate the cartridge reset routines.
7. Before placing the vehicle back into service, perform the
Operational Test.

2. Inspect the visible parts of the replacement parts for
damage.
3. Inspect the pneumatic ports for deep scuffing, gouges,
or nicks that may prevent an air-tight seal.
NOTE: If any of the conditions in Steps 1 to 3 are noted, repair
the damage or replace the GSAT core module as necessary.
4. Inspect all air line fittings for corrosion. Clean, repair,
or replace corroded or damaged fittings as necessary.

IMPORTANT
Failure to maintain and replace corroded fittings may
result in poor vehicle performance and may be a violation
of commercial vehicle regulations.

3

OPERATIONAL TEST
Before placing the vehicle in service, perform the following
tests.
1. Close all of the reservoir drain cocks.
2. Start the vehicle. With the engine at 1800 rpm, build
up system pressure to system cutout while observing
that both service reservoir dash gauges show a rise in
pressure from 0 psi (0 kpa) to system cutout. If either
gauge fails to display this condition, stop testing and
check the installation. Note that the GSAT system
regenerates/purges with an audible escape of air
when system cutout pressure is reached. Refer to
SD-24-250D, Bendix® GSAT® (Global Scalable Air
Treatment) System for Daimler® Truck North America
(DTNA), on B2Bendix.com for more information on
troubleshooting a GSAT system.
NOTE: The service reservoir pressures will drop slightly
during regeneration/purge.
3. Fan down the service brakes by repeatedly pressing
and releasing the service brakes to reduce system air
pressure to system cut-in. Note that the system – once
again – builds to full system pressure and is followed
by a regeneration/purge event at the GSAT air dryer
primary exhaust.

24/7/365 ACCESS
FULL SERVICE AT YOUR FINGERTIPS

4. To verify proper park brake function, use the Hand Control
Unit (HCU) to release and apply the tractor park brakes
several times. The HCU and/or dash cluster should
illuminate, indicating a proper park state. Refer to the
applicable Operator's Manual for HCU statuses.
5. It is recommended that the following items be tested for
leakage to ensure the GSAT will not cycle excessively:
a. A
ir brake system (Refer to the Bendix® Air Brake
Handbook, BW5057, on B2Bendix.com)
b. Compressor unloader mechanism
c. GSAT core module pneumatic connections
d. D
rain cock and safety valve in first (supply) reservoir
(if equipped)
e. A
ll air connections leading to and from the first
(supply) reservoir (if equipped)

TECHNICAL ASSISTANCE
For additional assistance, the Bendix Tech Team can
be reached by email at [email protected] or by
phone at 1-800-AIR-BRAKE (1-800-247-2725), option 2.
Representatives are available Monday through Thursday,
8:00 a.m. – 6:00 p.m., and Friday, 8:00 a.m. – 5:00 p.m. ET.

1-800-AIR-BRAKE (1-800-247-2725)
[email protected]

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Any references in this document to DAIMLER and any other company or trademark are solely for
identification and cross reference purposes. The trademarks are the property of their respective companies.
Unless otherwise indicated, the trademarks used in this document, including Bendix,
are United States trademarks owned by, or licensed to, Bendix Commercial Vehicle Systems LLC.

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S-1707 Rev 000 © 4/2025 Bendix Commercial Vehicle Systems LLC, a member of Knorr-Bremse • All Rights Reserved