4.4.2 Inspect the rotor surface. See Figure 25. The type
of rotor, and also the size, depth and direction of
the imperfections, must all be considered.

H

F
No action is needed
for small cracks
spread over the
surface (e.g. Area F)

Rotor
Friction
Surface
Width “f”

Area
F

Area
H

f

Area G
G
Cracks reaching
either edge of the
rotor
are not
acceptable
for either
type of
rotor

• For standard Bendix brand rotors,
cracks running in a radial direction – like
spokes of a wheel (see Area H) – less
than 0.06 in. (1.5 mm) deep or wide are
acceptable if they do not reach either
edge (see Area G). Cracks are only
acceptable if the length of the crack is
less than 75% of dimension “f” (the width
of the rotor contact area).

Area J

• For Bendix® Splined Disc® rotors,
radial cracks are only acceptable if they
are less than 0.04 in. (1.0 mm) deep
or wide and if they do not reach either
edge (see Area G). Crack lengths must
be less than 75% of dimension “f” (the
width of the rotor contact area).

J
Circumferential
grooves, as in Area
J, are acceptable
if less than 0.06 in.
(1.5 mm) deep.

Figure 25 – Examples of Acceptable and Non-acceptable Rotor Conditions
16

In addition, follow the
recommendations of
the vehicle and rotor
manufacturer.
Note: Axles should
have either all Bendix
Splined Disc (or all
conventional) rotors.

MACHINING OF BENDIX® SPLINED DISC® ROTORS IS
NOT PERMITTED.

1
Caliper

CAUTION: Always maintain air disc brake pads and rotors
within specifications. Excessive pad or rotor wear will
degrade braking performance.

9
Inner
Boot

7
Brass
Bushing

5
Guide Pin

10
Cap

Periodic inspection of the Bendix Splined Disc attachment
hardware is recommended to ensure optimum braking
performance. Bendix recommends verifying the torque on
the spring element fasteners whenever a brake inspection
is performed.

AFTER MACHINING/TURNING, THE MINIMUM ROTOR
THICKNESS FOR BENDIX® BRAND ROTORS MUST
BE AT LEAST 1.535 - 1.575 IN. (39 - 40 MM.). FOR
OTHER BRANDS, CONSULT THE MANUFACTURER’S
G U I D E LI N ES . A L SO, CH ECK TH E V E H I CLE
MANUFACTURER’S RECOMMENDATIONS. FAILURE
TO COMPLY MAY RESULT IN BRAKE FAILURE AND IN
SERIOUS INJURY OR DEATH. MACHINING OF BENDIX
SPLINED DISC ROTORS IS NOT PERMITTED.

LONG
BEARING
SIDE

SHORT
BEARING
SIDE

4.4.4 Rotor Replacement
An axle is permitted to have only all Bendix Splined
Disc, or all conventional, rotors.
When replacing rotors, be sure to adhere to the vehicle
manufacturer’s recommendations, including bolt tightening
torques. It is recommended to install only Bendix® brand
rotors, and also that the pads should be replaced (as an
axle set) at the same time.
Non-Bendix® brand rotors. If a non-Bendix brand rotor is
used, confirm that it complies to the vehicle manufacturer’s
recommendations.

6 Guide Sleeve
Outboard

Caliper
Movement

Inboard

68
Cap

39
Caliper Bolt
9 Inner Boot

4 Guide Pin

Figure 26 – Guide Pins
12 Pad Assembly
1
Carrier

CAUTION: The use of non-approved brake rotors may
reduce levels of safety and invalidate the warranty.
See Section 5.7 for reinstallation procedures.

4.5 GUIDE PIN BEARING INSPECTION
CAUTION: Follow all safe maintenance practices.
This guide pin inspection should be carried out if the
technician cannot move the caliper during a Caliper
Movement Test (See Sections 2.2 and/or 4.1).
Measure the range of travel along the guide pin
bearings:

Magnetic
Dial‑Gauge
Measures
Range Here

2
Caliper

Figure 27 – Magnetic Dial-Gauge In Use

4.5.1 Remove the Pads (See Section 4.3). Using hand
pressure only (no tools), the caliper (1) should slide
freely along the whole length of the guide pins. This
movement should be at least 0.95 inch (25 mm)
when the pads are not present. If the movement
is less than this amount, replace the caliper/carrier
assembly.
17

Measure the “play” (range of movement) in the guide
pin bearings:
4.5.2 See Figures 26 and 27. With the wheel removed,
remove the pad retainer bar (11). Temporarily
replace the pads with two new pads (12). Attach
a magnetic dial-gauge holder to the carrier (2) on
the short bearing side of the caliper (1). Use the
measuring point on the caliper (1) – see the callout
in Figure 27. Press the caliper in the direction of
the carrier (2) and set the dial-gauge to zero.
4.5.3 Place a suitable tool (e.g. a large flat-blade
screwdriver) between carrier (2) and caliper (1) and
use light hand force to move the caliper away from
the carrier, until the movement stops. Read the
maximum value on the dial-gauge. See Figure 27.
If the value is greater than 0.039 in. (1.0 mm), replace
the guide pin bushings (See Section 5.6) OR replace the
caliper/carrier assembly (See Section 5.3).
Inspect the guide pin inner boots:
4.5.4 See Figures 28 and 29. With the pads removed,
slide the carrier by hand to the inboard position
(See Figure 28). By looking through the opening
where the pads are installed – and also from
below – inspect the inner boot (9) for each of the
guide pins. INSPECT FOR DAMAGE, CUTS AND
CRACKS. Replace damaged boots immediately to
prevent dirt and/or moisture affecting the movement
of the guide pins (See Section 5.4). Damaged or
corroded guide pins will impair the operation of the
brake.
In addition, during installation, the boots are
compressed to minimize the amount of air trapped
within them. Observe as you move the carrier back
towards the outboard position; the boots should only
expand outwards a small amount due to trapped
air. The boots should normally (due to their ribbed
construction) contract back into place as the caliper
moves on the guide pins. The boots are not airtight and so some trapped air is normal; excess air
trapped will dissipate.

Inspect
Boot

Figure 28 – Guide Pin Boot Inspection (This Image
Does Not Show the Carrier)
18

4.5.5 Inspect the original pads (See Section 4.3) and they
may be reused if they are in good condition with
sufficient pad thickness.

4.6 TAPPET AND BOOT ASSEMBLY
INSPECTION

4.6.1 In order to inspect the tappet and boot assembly,
remove the pads (12) (See Sections 4.3 or 5.2) and
advance the shear adapter (61) clockwise.
CAUTION: NEVER EXTEND THE TAPPET MORE THAN
1.75 in. (44.5 mm). See Figure 29. Over-extending the
tappet will result in the tappet losing engagement with
the synchronizing mechanism. Since the mechanism
can only be set at the manufacturing plant, the caliper/
carrier assembly must be replaced if this happens.
4.6.2 INSPECT THE TAPPET AND BOOT ASSEMBLIES
(13) FOR EVIDENCE OF DAMAGE, CUTS,
CRACKS, TEARS, AND EVIDENCE OF
CORROSION, ETC. Damaged boots lead to the
penetration of dirt and moisture, and can promote
corrosion and impair the operation of the brake.
Replace as necessary (See Section 5.5).

13

Extend LESS THAN
1.75  in. (44.5 mm.)
Figure 29 – Permitted Tappet Extension
Where the tappets and boots pass the inspection, retract
the tappets using the shear adapter.
When installed, the boots are compressed to minimize the
amount of air trapped within them. Observe as you move
the tappet back using the shear adapter; the boots should
only expand outwards a small amount due to trapped air.
The boots should normally (due to their ribbed construction)
contract back into place as the tappets move. Note: If the
bellows have excess trapped air, then with the tappets
retracted, remove and re-install the actuator to vent the
excess trapped air (See Section 5.4).
Follow the reinstallation steps for the brake pads (See
Section 5.2).

SECTION FIVE: MAINTENANCE KITS AND PROCEDURES
Section

5.0
5.1
5.2
5.3

Section Five

Section

Page

5.4
Spring or Service Brake . . . . .
5.5 Tappet & Boot Assemblies, and
Tappet Inner Seal . . . . . . .
5.6
Guide Pin and Boot Assemblies . .
5.7
Bendix® Splined Disc® Hub Rotor . .

Maintenance Kits . . . . . . . 20-21
Air Disc Brake Shield Kit . . . . .
22
Pad Replacement . . . . . . .
23
Caliper/Carrier/Actuator Assembly . 25-26

(Wheel turns
Type B toward fixed pin
side of ADB)
44
Pad Retainer Pin

Type A
(Fixed pin)

35
11 Pad Retainer

Wheel Rotation
(typically left
hand)

Wheel Rotation
(typically right
hand)

161
Tappet Bushing
13 Tappet
and Boot
Assembly

U-shaped Rotor

29-32
33-38
39-41

18/2
Service
Actuator

12/2 Pad Holder Spring
(Note: Pad Assembly
10
consists of 12/1 plus 12/2)
40 Cap
12/1 Pad
5 Caliper
Guide Bolt
Pin
7
Brass
Bushing

22
Inner Seal

Shield
Kit
(Drive or
Steer)

. 28

18/1 Spring Brake
Actuator

26 Spring Clip

45
Washer

Page

68
Cap
39 Caliper Bolt

Actuator
Hardware

61 37*
Shear
Adapter

4 Guide Pin
6 Guide Sleeve
Carrier
Mounting
Hardware

1
Caliper
(or Caliper Kit)

9
58 Inner Boot
Ring

*37 Adjuster
Caps (2 styles
supplied in kits)

Bendix® ADB22X™
Anchor Plate
2A
Bendix®
ADB22X™
Carrier

(Rotor Shield for Trailers)
U-shaped
Rotor
Fasteners

2B
Bendix®
ADB22X-V™
Carrier

SD-1
Drive Hub

SD-3

Splined Disc
Rotor (SD)

SD-2
Splined Disc®
Rotor Hardware
SD-1, -2, -3

Bendix
ADB22X-V
Anchor
Plate

Carrier
Mounting
Hardware

See Section 5.2 for
exploded view of electronic
wear indicator.

Steer Hub

Figure 30 – Exploded View - Bendix ® ADB22X ™, ADB22X-V ™, and ADB22X ™-LT Air Disc Brakes
19

5.0 MAINTENANCE KITS FOR BENDIX® ADB22X™, ADB22X-V™ AND ADB22X™-LT AIR
DISC BRAKES
Below is a list of some of the available kits. See Figure 30 for an exploded view showing the components listed.
Kit
Pad Kit (axle set)

Piece Number

Components Included in Kit

K070796

BX275 Kit (11, 12/1, 12/2, 26, 37, 44, 45, 61) Standard Service

K109113

BX283+ Kit (11, 12/1, 12/2, 26, 37, 44, 45, 61) Severe Service

K129276

BX276 Kit (11, 12/1, 12/2, 26, 37, 44, 45, 61) Trailer and Truck

Splint Kit (box of 25)

803151

(26)

Shear Adapter (box of 10)

802455

(61)

Tappet/Boot Kit (wheel end kit)

K092079

Adjuster Cover (box of 10)
Guide Pin, Seal and Boot Kit
(wheel end kit)
Guide Pin Boot Kit

802643

(37)

803114

(4, 5, 6, 7, 9, 10, 37, 39, 40, 58, 61, 68)

Guide Pin Grease

Service Actuators

NG-3 Piston-Style
Spring Brake Chambers

Double-Diaphragm-Style
Spring Brake Chambers

Caliper-Carrier Assembly
(Includes 803114)

Caliper Kit
(rationalized)
Includes 803114

Carrier Kit

Hubs

Table 2 – Maintenance Kits
20

K023768
II14525

(13, 22, 161)

(9, 10, 37, 39, 40, 58, 61, 68)
White (5 grams)

K021964

White (500 grams)

K028039

Bendix® Type 14 Universal (9, 18/2)

K028226

Bendix® Type 16 Universal (9, 18/2)

K028022

Bendix® Type 18 Universal (9, 18/2)

K028225

Bendix® Type 20 Universal (9, 18/2)

K028238

Bendix® Type 22 Universal (9, 18/2)