NHTSA ID Number: 10115858
Manufacturer Communication Number: SD237541
TSB/Document Date: 2017-08-25
Summary
Service Data Sheet for the Bendix
ADB22X?, ADB22X-V? and ADB22X?-LT Air Disc Brakes (ADB) use a floating caliper design to provide foundation braking on all axles of heavy commercial vehicles, buses and trailers.
SD-23-7541
®
Bendix® ADB22X™, ADB22X-V™ & ADB22X™- LT Air Disc Brakes
SECTION ONE: AIR DISC BRAKE OVERVIEW
1.1 DESCRIPTION
Bendix® ADB22X™, ADB22X-V™ and ADB22X™-LT Air
Disc Brakes (ADB) use a floating caliper design to provide
foundation braking on all axles of heavy commercial
vehicles, buses and trailers. Bendix air disc brakes provide
safety and performance as well as ease of service.
The ADB22X disc brakes mount to the axle's anchor plate
(torque plate) using fasteners that are installed parallel
to the axle, while the anchor-plate fasteners used for the
Bendix ADB22X-V air disc brakes install at right angles to
the axle. The ADB22X-LT air disc brake is designed for
trailer applications.
Available with or without a combination spring brake unit,
these brakes may also include optional wear sensors and
wear diagnostic equipment.
Section One
Section
1.1
1.2
1.3
1.4
1.5
1.5.1
Page
Description . . . . . . . . . .
Air Disc Brake Identification . . . . .
Rotor Identification . . . . . . . .
Wear Sensor Identification . . . . .
Operation . . . . . . . . . . .
Brake Release and Adjustment . . . .
1
1
4
4
4
4
1.2 Air Disc Brake Identification
Locate the identification label near the guide pin housing.
See below for information about the label fields used.
Label
Figure 2 – Typical Part Number Label Location
Bendix Part Number
Serial No.
Customer Part
Number
Figure 3 – Part Number Label Information
Figure 1 – Bendix ® ADB22X ™ Air Disc Brakes
1
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, or a Bendix ® AD-9si ® 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.
2
WARNING: Not all wheels and valve stems
are compatible with Bendix Air Disc Brakes. Use
only wheels and valve stems approved by the
vehicle manufacturer to avoid the risk of valve
stem shear and other compatibility issues.
WARNING: AVOID CREATING
DUST. POSSIBLE CANCER AND LUNG
DISEASE HAZARD.
While Bendix Spicer Foundation Brake LLC does
not offer asbestos brake linings, the long-term
affects of some non-asbestos fibers have not
been determined. Current OSHA Regulations
cover exposure levels to some components of
non-asbestos linings, but not all. The following
precautions must be used when handling these
materials.
• Avoid creating dust. Compressed air or dry
brushing must never be used for cleaning brake
assemblies or the work area.
• Bendix recommends that workers doing brake
work must take steps to minimize exposure
to airborne brake lining particles. Proper
procedures to reduce exposure include working
in a well-ventilated area, segregation of areas
where brake work is done, use of local filtered
ventilation systems or use of enclosed cells with
filtered vacuums. Respirators approved by the
Mine Safety and Health Administration (MSHA)
or National Institute for Occupational Safety and
Health (NIOSH) should be worn at all times during
brake servicing.
• Workers must wash before eating, drinking or
smoking; shower after working, and should not
wear work clothes home. Work clothes should
be vacuumed and laundered separately without
shaking.
• OSHA Regulations regarding testing, disposal
of waste and methods of reducing exposure
for asbestos are set forth in 29 Code of Federal
Regulations §1910.001. These Regulations
provide valuable information which can be utilized
to reduce exposure to airborne particles.
• Material Safety Data Sheets on this product, as
required by OSHA, are available from Bendix.
Call 1‑800‑247‑2725 and speak to the Tech Team
or e‑mail [email protected]
Knorr or Bendix® Air Disc
Brake
ADB22X™-LT
Max.
permissible
Bendix®
cylinder
size
ADB22X™
of premature wear or failure, verify the brake
chamber is sized appropriately for the application.
An over-sized brake chamber can result in
excessive force being applied to the brake
pads and rotors. Additionally, under-sized brake
chambers can result in too little braking force
being applied to the brake and could increase
the time and distance needed to stop the vehicle.
See the table below for brake chamber guideline.
SN-7™
WARNING: If pads or rotors show signs
Service
brake
system
T30
T24
T18
Parking
brake
system
T30/24
HFL3
T24/24
HFL1
T18/24
DDSB
SERVICE DATA INDEX
Section One: Air Disc Brake Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Safe Maintenance Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Air Disc Brake Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Rotor Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Wear Sensor Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5.1 Brake Release and Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Section Two: Preventive Maintenance Schedule and Wheel-On Inspections . 7
2.0 Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Brake Pad and Rotor Inspections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Running Clearance Quick Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Section Three: Troubleshooting Procedure Flowchart . . . . . . . . . . . . . . . . . 10
Section Four: Wheel-Off Maintenance Inspections . . . . . . . . . . . . . . . . . . . . . 12
4.0 Wheel-Off Inspections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1 Caliper Movement Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2 Adjuster Mechanism Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Inspect The Brake Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4 Inspect The Rotor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.5 Guide Pin Bearing Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.6 Tappet And Boot Assembly Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Section Five: Maintenance Kits And Procedures . . . . . . . . . . . . . . . . . . . . . . . 19
5.0 Maintenance Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.0.1 General Information About Bendix Air Disc Brake Maintenance . . . . . . . . . 21
5.1 Air Disc Brake Shield Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.2 Pad Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.3 Caliper/Carrier/Actuator Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.4 Spring or Service Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.5 Tappet & Boot Assemblies, and Tappet Inner Seal Replacement . . . . . . . . 29
5.6 Guide Pin and Boot Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
5.7 Bendix® Splined Disc® Hub Rotor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Contacting Bendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3
1.3 Rotor Identification
1.5 Operation
See Figure 4 to help you identify which type of rotor is used
on the axle being inspected. Note that the maintenance
inspection procedure will depend on the type of rotor
installed.
Bendix air disc brakes convert air pressure into braking
force. (See Figure 6.) When the vehicle brakes are
applied, air enters the service brake chamber through the
supply port, applying pressure within the diaphragm. The
pressure expands the diaphragm – applying force to, and
moving, the pressure plate and pushrod forward. The
pushrod acts against a cup in the internal lever – which
pivots on an eccentric bearing – moving the bridge. Moving
against a return spring, the bridge transfers the motion to
two threaded tubes and tappets, which move the inner
brake pad. The inner brake pad (from its normal position
of having a running clearance between it and the rotor)
moves into contact with the brake rotor. Further movement
of the bridge forces the caliper – sliding on two stationary
guide pins – away from the rotor. That, in turn, pulls the
outer brake pad into the rotor. The clamping action of the
brake pads on the rotor applies braking force to the wheel.
Bendix® Splined
Disc® Rotor
Conventional
Rotor
Service Brake
Chamber
Inner Brake Pad
Outer Brake
Pad
Figure 4 – Rotor Identification
Lever
Pressure
Plate
Supply Port
Pushrod
Return Spring
CAUTION: Rotors may not be mixed on a single axle:
axles are only permitted to have all conventional or all
Bendix® Splined Disc® brake rotors.
1.4 Wear Sensor Identification
See Figure 5 for the electronic wear sensor that may be
present.
104
Cable Protection
Plate
101
Sensor
101
Sensor
Rotor
Bridge
Eccentric Bearing
Figure 6 – Sectional View Showing Brake Operation
105
Cable Guide
(2 alternate
designs used)
103
Cable to Electrical
Supply
Sensor . . . . . . . . . . . . . . . . . . 101
Cable to Electrical Supply . . . 103
Cable Protection Plate . . . . . . 104
Cable Guide (two designs) . . 105
Consult the instruction sheet included with wear
indicator kits for installation information.
Figure 5 – Electronic Wear Indicator Components
4
Diaphragm
1.5.1 Brake Release and Adjustment
When the vehicle brakes are released, the air pressure
in the service brake chamber is exhausted and the return
springs in the chamber and the bridge return the air disc
brake to a neutral, non-braked position. To maintain the
running clearance gap between the rotor and the brake
pads over time, the non-braked position is mechanically
adjusted by a mechanism in the caliper. The adjustment
mechanism operates automatically whenever the brakes
are activated, to compensate for rotor and brake pad wear
and to keep the running clearance constant. During pad
or rotor maintenance, the technician manually sets the
system’s initial non-braked position. The total running
clearance (the sum of clearances on both sides of the
rotor) should be between 0.024 to 0.043 in. (0.6 to 1.1 mm).
1
Caliper
12
Pad
Assembly
9
58 Inner Boot
Ring
5
22
Inner Seal
Guide Pin
7
Brass Bushing
Top Sectional View
40
Caliper Bolt
10
Cap
161
Tappet
Bushing
23
Adjuster Unit
32
Chain Wheel
61
Shear Adapter
16
Threaded Tube
13
Tappet and Boot
Assembly
45 Washer
26
Spring Clip
37
Adjuster Cap
27 Spring
44
Pad Retainer Pin
30
Chain
11
Pad Retainer
17
Bridge
22
Inner
Seal
16
Threaded Tube
161
Tappet
Bushing
13
Tappet
and Boot
Assembly
33
Wear Sensor
24
Turning
Device
6
Guide Sleeve
2
Carrier
2
Carrier
39
Caliper Bolt
Side Sectional View
68
Cap
58
Ring
Pad Assembly 12
12
Pad
Assembly
18/1 Spring Brake or
18/2
Brake Chamber
9
Inner
Boot
4
Guide Pin
Short Caliper Bolt
Sectional View
46
Rotor
43
Bolt
27
Spring
19
17 Lever
Bridge
20
Eccentric
Bearing
Figure 7 – Sectional Views
5
Fixed-pin
(longer pin)
For Bendix® Air Disc Brakes, as a
vehicle travels forward, the wheel
always rotates towards the fixedpin side of the caliper first.
Floating pin
‘A’ or ‘B’ is
cast here
Type ‘A’
44
Pad Retainer
Pin
Type ‘B’
35 Double-Diaphragm-Style
Spring Brake Chamber
11 Pad Retainer
18/1 Spring Brake
Actuator
18/2
Service
Actuator
26 Spring Clip
12/2 Pad Holder Spring
ee
n
l R ot ati o
On most vehicles, Type A calipers
are used on the passenger’s side
of the vehicle. (There are some
rare driver’s side applications.)
(Note: Pad Assembly
consists of 12/1 plus 12/2)
45
- Mixes well with conventional fluids
- Low-moisture formula provides excellent vapor lock...
- Ideal for hydraulic and disc brakes
- Provides an extra margin of safety in extreme braking...
- Mix of polyglycol ethers ensures hot brake-system operation...
- Excellent for ABS, disc and drum brake systems
- Delivers braking power when needed by avoiding a spongy...
- Both wet and dry boiling points exceed the minimum...
If the PDF is very large, it may not load in the preview below.
Some older TSBs had multiple PDFs — visit the NHTSA Website to view all PDFs.
If the TSB PDF does not show, download or view it on the NHTSA Website.
Click on the (+) Plus Sign
Then Click on Associated Document(s)
Search NHTSA Database for Recalls
Search NHTSA Database for Vehicle Investigations
View Latest Vehicle Investigations
Search NHTSA Database for Vehicle Complaints
View Latest Vehicle Complaints
TSB/Document ID: SD237541
Replacement Service Bulletin Number:
MFR Communication Date: 2017-04-25
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: SERVICE BRAKES, AIR
MFR Component System:
MFR Component Subsystem:
Previous TSB | Next TSB |
- [Notice] When you receive a used device, it may be a customer return resold by Amazon without inspection. You can exchange it for a new one through Amazon. As this situation is unavoidable, we sincerely apologize. For any issues, contacting us via Amazon's "Messages" is the best way. THINKSCAN 689BT Bidirectional Scan Tool Can Be Used Immediately After It is Turned On, Without Complicated Registration Process, Which is More Convenient & Quick.
- Full Bi-Directional Control & 3000+ Active Tests: Take control and test components like actuators, fuel injectors, relays, and cooling fans in real time. You’ll quickly see if the problem is in the part itself or the control module — saving you hours of guesswork and frustrating trial-and-error.
- Advanced ECU Coding Capabilities: Handle module matching and hidden feature activation with confidence. When you replace an ECU or want to customize settings, this obd2 scanner diagnostic bi directional tool gives you the professional-level capabilities you need without the dealership price tag.
- 34+ Useful Reset and Maintenance Functions: Complete everyday service tasks smoothly with a wide range of helpful reset and maintenance functions. Whether you’re keeping up with regular upkeep or tackling a specific job, this scanner makes maintenance simpler and less stressful for both DIYers and pros.
- Comprehensive Full System Diagnostics: Diagnose every major system — Engine, Transmission, ABS, SRS, TPMS, and more — all in one place. Finally stop wondering if you’re missing something important; get the full picture and clear codes with ease.
- Top Reasons to Choose the D7S OBD2 Scanner: XTOOL D7S car scan tool, an upgrade of XTOOL D7, offers comprehensive features for automotive technicians, workshops, and DIY enthusiasts 1. Upgraded Hardware: 2+64GB memory, rear camera, intuitive interface, foldable bracket 2. Complete Diagnostics: FCA
Autoauth, OE-level all system scan, 39+ maintenance services, 4K+ bidirectional, CANFD/DoIP protocol 3. Advanced Capabilities: ECU c0ding, PMI functions 4. Wide Compatibility: Support 10,000+ models, covering 99% vehicle brands 5. Multi-language: Available in 22+ languages, No IP Restrictions 6. 3-Year Updates: Save 300 bucks on software updates for the latest features and optimizations - 2026 Upgraded D7S Car Scanner Features: The newly 2026 D7S V2.0 scanner for car brings exciting features for advanced vehicle diagnostics and enhanced user experience 1. FCA AutoAuth: Now supports FCA SGW module for Chrysler, for Jeep, for Dodge (2018+), for Fiat (2017+), enabling faster vehicle communication without gateway restrictions 2. PMI (Offline ECU Pr0gramming): Allows for Ford, for Lincoln, and for Mazda ECU pr0gramming for new modules 3. Optimized Diagnostic Report 2.0: Personalized reports with logos and customer info for auto shops. Note: Compatibility varies by cars, please check before order
- 39+ Services/Resets/Adaptations/Relearns/Calibrations: XTOOL D7S full system car scanner diagnostic tool tackles 99% of common car issues through its 36+ special functions, including Oil Reset, EPB, SAS, BMS, Throttle Reset, Injector C0ding, ABS Bleed, TPMS Reset, Power Balance, etc and also covers specific-vehicle functions like Crank Sensor Relearn, ABS Initialization, Cylinder Power Balance, Fuel Trim Reset, Idle Relearn etc. This car diagnostic scanner enhances efficiency, making repairs and maintenance hassle-free. Tip: DO NOT for All vehicles, please check compatibility first
- Cost-effective ECU C0ding Scan Tool for Specific Brands: Enhance your vehicle's performance with XTOOL D7S! This obd2 scanner all systems bidirectional offers advanced capabilities at an affordable price, supports online for BMW, for Benz and offline for BENZ, for MIT, along with PMI functions for Ford, for Mazda, and for Lincoln. Ideal for technicians and DIY enthusiasts, this automotive scanner diagnostic tool optimizes vehicle performance and enhances the driving experience. Note: Not for all cars and modules, please send car VIN to check the compatibility before purchase
- OE All System Diagnostic & 8 Pids Graphing: XTOOL D7S is a comprehensive all system bi directional obd2 scanner that delivers dealer-level diagnostics, completely controlling over your vehicle’s performance and health. This automotive scan tool can read and clear DTCs, view live data and ECU information, retrieve freeze frames, and perform active tests and full obd2 functions. This bi-directional scan tool can can identify your vehicle's make, model, and year information with just one click and show up to 8 PIDs live data with options for CSV viewing, playback, and recording for in-depth analysis. It is easy-to-use for both professionals and beginners, helping pinpoint issues efficiently
- 【✅Compared to BOSSCOMM IF742, IF745 Offers Full-System Diagnostics】The BOSSCOMM IF745 car diagnostic scanner is an upgraded model of IF742. In addition to supporting all OBD2 Code Reader functions and 6 reset options (ABS/EPB/SAS/BMS/Oil/Throttle), it expands diagnostics from 4 systems (Check Engine/ABS/SRS/Transmission) to vehicle All systems, including Steering, Suspension, and Body Electronics. This provides deeper, more comprehensive diagnostic capabilities.
- 【✨10 OBD2 Functions】The BOSSCOMM IF745 scan tool’s DTC Lookup instantly translates fault codes into user-friendly explanations, its I/M Readiness feature streamlines emissions testing with a single tap, and Freeze Frame lets you pinpoint the exact moment of a fault for in-depth root-cause diagnosis. Combined with a live data dashboard and advanced diagnostics (O2S, OBMon, EVAP), it delivers comprehensive insights for confident troubleshooting.
- 【✨Deep Diagnostics for All Vehicle System Modules】Beyond code reading/clearing and ECU information retrieval, our all-in-one data stream feature lets you inspect all current fault codes and their locations across the vehicle’s systems. This vehicle code reader helps you turn off dashboard warning lights and perform a comprehensive self-check of your car at home—no more back-and-forth trips to the repair shop or hefty inspection fees.
- 【✨6 Essential Resets: ABS Bleeding, Oil, EPB, SAS, Throttle, BMS】The BOSSCOMM IF745 obd2 scanner diagnostic tool swiftly purges air from brake lines to restore braking sensitivity, fine-tunes maintenance cycles to eliminate false alerts, resolves parking brake issues with one-click control, recalibrates steering sensors for stability, optimizes engine idling/acceleration for smoother performance, and deeply resets battery systems to extend lifespan and range via precise parameter adjustments.❗NOTE: Does NOT support bidirectional control, coding, or programming.
- 【✨10,000+ Car Models, AutoVIN, 13 Languages】The BOSSCOMM IF745 vehicle scanner diagnostic tool covers 73+ global car brands and offers support in 13 languages, making it perfect for DIYers, auto mechanics, or as a thoughtful gift. With a single-click AutoVIN feature, it instantly retrieves vehicle serial numbers, streamlining diagnostics for users globally. This adaptable tool balances user-friendliness with precision, catering to both personal and professional requirements.✅Unsure about compatibility? Compatibility will vary on vehicles' model and year, pls reach us via 📧 [email protected] 📧 before purchase.
This product presentation was made with AAWP plugin.