Bendix® GSAT® (Global Scalable Air Treatment) Air Dryer Replacement Kits
for Volvo® Trucks
KIT COMPONENTS
See Figure 1. The following components are in the Bendix®
GSAT® (Global Scalable Air Treatment) air dryer kits for
Volvo® trucks:
Item No.

Component

Quantity

1

Air Dryer (Attached)

1

2

Seal

1

Not Shown

Heater

1

Bendix Volvo Kit Part Number: K202684K57
Volvo Kit Part Number: 23771615
Bendix Mack® Kit Part Number: K202685K57
Mack Kit Part Number: 23771617
Item No.

Component

Quantity

3

Air Dryer (Detached)

1

Not Shown

Heater

1

Bendix Volvo Kit Part Number: K273513SC
Bendix Mack Kit Part Number: K273514SC
Item No.

Component

Quantity

4

Air Dryer (CFL Detached) PRI

1

Not Shown

Heater

1

Bendix Volvo Kit Part Number: K273515SC
Bendix Mack Kit Part Number: K273516SC
Item No.

Component

Quantity

5

Air Dryer (CFL Detached) SEC

1

Not Shown

Heater

1

Bendix Volvo Kit Part Number: K273517SC
Bendix Mack Kit Part Number: K275583SC

When replacing air dryer assembly, it is mandatory that
the air dryer cartridge and carbon filter be replaced. For
replacement kit part numbers and instructions, refer to
S-1693, Bendix® GSAT® (Global Scalable Air Treatment)
Air Dryer Cartridge and Filter Kits for Volvo® Trucks,
on B2Bendix.com.

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

1

2

Air Connection
Port ID

Function/
Connection

Port Size
ISO 4039-2

Maximum
Torque

11 IN

Energy Inlet
Compressor

M22x1.5

29.5+5 ft-lb
(40+7 N•m)

12 IN

Energy Inlet
External Air Fill

M22x1.5

29.5+5 ft-lb
(40+7 N•m)

2.1 DEL

Energy Outlet to
Detached Core
Module

M22x1.5

29.5+5 ft-lb
(40+7 N•m)

4.5 CON

Control Line to
Detached Core
Module

M12x1.5

18+3 ft-lb
(25+5 N•m)

3 EXH

Exhaust

n/a

n/a

M12 Mounting

GSAT to Vehicle
Mounting

M12x1.75

55+11 ft-lb
(75+15 N•m)

Table 1 – Air Connections

DISASSEMBLY
Air Dryer (Attached Variant)
3, 4, 5

NOTE: Identify and mark all air line connections on the air
dryer for reinstallation ease.
1. Disconnect all air line connections from the air dryer.
2. To remove the air dryer from the core module, first remove
the air dryer cartridge to access the mounting bolts from
the air dryer to the core module.

Figure 1 – Air Dryer Kits

DESCRIPTION
IMPORTANT
Do not install the air dryer included in this kit if it does
not match the one being removed.
These kits are used to replace the Bendix® GSAT® (Global
Scalable Air Treatment) air dryer. These are not retrofit
kits. These kits cannot be installed on vehicles that do not
have an existing GSAT system. Be sure to verify the air
dryer included in this kit is identical to the air dryer you
are replacing. Ensure both air dryers have the same port
configuration, heater voltage, and mounting configuration in
the same locations.

VEHICLE PREPARATION
1. Park the vehicle on a level surface and chock the wheels.

3. Using an appropriate filter wrench (if necessary), loosen
the old cartridge and remove it from the air dryer housing
by turning in a counter-clockwise direction. Be careful
not to allow dirt or other contaminants to fall into the air
dryer housing. Discard the cartridge.

IMPORTANT
When replacing air dryer assembly, it is mandatory that
the air dryer cartridge and carbon filter be replaced. For
replacement kit part numbers and instructions, refer to
S-1693, Bendix® GSAT® (Global Scalable Air Treatment)
Air Dryer Cartridge and Carbon Filter Kits for Volvo®
Trucks, on B2Bendix.com.
4. Once accessible, remove the carbon filter from the air
dryer body and discard. See Figure 2.

2. Turn the ignition switch OFF.
3. Drain all reservoirs to 0 psi (0 kpa).

No Carbon Filter

4. Clean the exterior of the air dryer body, cartridge, and
core module silencers to remove any dirt and debris.

Always depressurize all air dryers and air reservoirs on
the vehicle to 0 psi (0 kpa) before servicing the air dryer.
Failure to drain the air pressure from all air dryers and
air reservoirs may result in injury and/or death.
Figure 2 – Carbon Filter

2

Carbon Filter Installed

5. Using a T-30 Torx® drive, remove the four (4) M6 mounting
bolts that secure the air dryer to the core module and
set them aside for reuse.

M6 Mounting
Bolts

5. Clean the mounting surface area of the core module with
a clean cloth and inspect for damage to the mounting
surface.

When replacing air dryer assembly, it is mandatory that
the air dryer cartridge and carbon filter be replaced. For
replacement kit part numbers and instructions, refer to
S-1693, Bendix® GSAT® (Global Scalable Air Treatment)
Air Dryer Cartridge and Carbon Filter Kits for Volvo®
Trucks, on B2Bendix.com.

ASSEMBLY
Air Dryer (Attached Variant)
1. Before mounting the air dryer to the core module, install
the new seal (included in kit) into the seal groove of the
air dryer mounting surface. Ensure the orientation tabs
are located in the correct slots, and fully seat the seal
into the groove.

M6 Mounting
Bolts
Seal

Figure 4 – Seal Installation
Figure 3 – M6 Mounting Bolts

6. Remove and retain the five (5) M12 mounting bolts that
secure the air dryer and attached core module to the
vehicle.
7. The air dryer can now be removed by pulling it away
from the core module, taking care to not damage the
alignment pins and the heater connection. Discard the
seal (a new seal is provided in the kit).
8. Clean the mounting surface area of the core module
with a clean cloth. Be careful not to allow dirt or other
contaminants to fall into the delivery bore of the core
module.
Air Dryer (Detached Variant)
NOTE: Identify and mark all connections on the air dryer for
reinstallation ease.
1. Disconnect all air line connections from the air dryer.
2. Disconnect the heater electrical connector from the air
dryer.
3. Remove and retain the three (3) M12 mounting bolts
that secure the air dryer to the vehicle.

2. Align the air dryer mounting alignment holes with the
alignment pins on the core module. Take care not to
damage the exposed heater connection pins.
3. Seat the air dryer to the core module. The heater pins
of the core module will engage with the air dyer heater.
4. Secure the air dryer to the core module with the four (4)
M6 mounting bolts set aside during disassembly.
5. Using a T-30 Torx drive, torque the air dryer to
the core module mounting screws to 71 in-lbs
(8 N•m) in a cross pattern.
6. Secure the air dryer to the vehicle using the original
five (5) M12 mounting bolts that were removed during
disassembly. Torque to 55 ft-lbs (75 N•m).
7. Connect all of the air connections to the new air dryer
as marked during the disassembly process.
8. Install the new air dryer cartridge and carbon filter per the
installation instruction S-1693, Bendix® GSAT® (Global
Scalable Air Treatment) Air Dryer Cartridge and Carbon
Filter Kits for Volvo® Trucks, which is shipped with the
replacement kit can be found on B2Bendix.com.

4. Remove the air dryer.
3

NOTE: If using a filter wrench, place the filter wrench on
areas A or B as shown in Figure 5 to avoid damage to
the cartridge. If a filter wrench is used in the middle of the
cartridge, damage may occur.
NOTE: When replacing the air dryer cartridge, the cartridge
lifetime wear and wetness content will need to be reset. Use
Bendix® ACom® Diagnostic Software, or a Volvo® diagnostic
tool, to initiate the cartridge reset routines.
9. Before placing the vehicle back into service, perform the
Operational Test.

OPERATIONAL TEST
Before placing the vehicle in service, perform the following
tests.
1. Close all of the reservoir drain cocks.
2. With the engine at 1800 rpm, build up system pressure to
system cutout while observing that both service reservoir
dash gauges rise equally 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 Bendix® GSAT® (Global Scalable Air Treatment)
system regenerates/purges with an audible escape of
air when system cutout pressure is reached.
NOTE: The service reservoir pressures will drop during
regeneration/purge.
3. Fan down 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.

Figure 5 – Air Dryer Cartridge Filter Wrench Placement

Air Dryer (Detached Variant)
1. Secure the air dryer to vehicle using the original three
(3) M12 mounting bolts that were removed during
disassembly. Torque to 55 ft-lbs (75 N•m).

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.
5. It is recommended that the following items be tested for
leakage to ensure the GSAT will not cycle excessively:

2. Connect all air connections to the new air dryer as marked
during the disassembly process.

a. A
ir brake system (Refer to the Bendix® Air Brake
Handbook, BW5057, on B2Bendix.com)

3. Install the new air dryer cartridge and carbon filter per the
installation instruction S-1693, Bendix® GSAT® (Global
Scalable Air Treatment) Air Dryer Cartridge and Carbon
Filter Kits for Volvo® Trucks, which is shipped with the
replacement kit can be found on B2Bendix.com.

b. C
ompressor unloader mechanism per manufacturer's
recommendation

NOTE: If using a filter wrench, place the filter wrench on
areas A or B as shown in Figure 5 to avoid damage to
the cartridge. If a filter wrench is used in the middle of the
cartridge, damage may occur.
NOTE: When replacing the air dryer cartridge, the cartridge
lifetime wear and wetness content will need to be reset. Use
Bendix ACom Diagnostic Software, or a Volvo diagnostic
tool, to initiate the cartridge reset routines.
4. Before placing the vehicle back into service, perform the
Operational Test.

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FULL SERVICE AT YOUR FINGERTIPS

1-800-AIR-BRAKE (1-800-247-2725)
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c. GSAT core module
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 techteam@bendix.com 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.

24/7/365 ACCESS
FULL SERVICE AT YOUR FINGERTIPS

1-800-AIR-BRAKE (1-800-247-2725)
TECHTEAM@BENDIX.COM

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Any references in this document to VOLVO, MACK, and any other company or trademark
are solely for identification and cross reference purposes.
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.

4

S-1694 Rev 004 © 12/2025 Bendix Commercial Vehicle Systems LLC, a member of Knorr-Bremse • All Rights Reserved