pad. Move the caliper fully inward and install the
inboard pad.

Inboard Pad
Figure 38 – Pad Removal
5.2.9 See Figure 38. Move the caliper fully inward and
remove the inboard pad, then move the caliper fully
outward and remove the outboard pad.
5.2.10 Repeat the pad removal procedure for the other
end of the axle.
5.2.11 Inspect the brake pads as shown in Section 4.3.
26

5.3 C ALIPER/CARRIER/ACTUATOR
ASSEMBLY

CAUTION: Follow all safe maintenance practices,
including those listed on page 2 of this document.
Park the vehicle (by other means than the foundation
brakes) on level ground and chock the wheels.
Figure 40 – Running Clearance Adjustment
5.2.18 Using a 10 mm, six-point box-end wrench, turn the
shear adapter (61) clockwise until the pads contact
the rotor. Note: Do not use an open-ended wrench
as this may damage the adapter. (See Figure 40).
5.2.19 Using the same tool, turn the shear adapter (61)
counterclockwise and listen for the sound of three
(3) clicks as the mechanism backs-off (increases)
the running clearance. (See Figure 37).
5.2.20 Select the correct replacement adjuster cap from
those supplied with the kit. Lightly grease adjuster
cap with Renolit® HLT2 white grease (part number
14525) and install the cap.
5.2.21 Push the new pad retainer bar (11) into the groove
of the caliper. Press down on the pad retainer bar,
and insert the pad retainer pin (44), with the pin
pointing downwards, where possible. (See Figure
33.) Install the supplied washer (45) and then the
spring clip (26).
Assemblies equipped with wear sensing: install
the pad retainer bar (11) such that the short lead
connected to the inboard pad is routed over the
top of the pad retainer bar (11) and the long lead
attached to the outboard pad is routed down the left
hand side of the retainer bar. (See Figure 34).
Install the wire in the wire shield, then clip the shield
onto the pad retainer bar as noted in 5.2.3. Make
sure the bent tab on the shield is aligned within the
notch in the retainer bar. Connect the wear sensing
harness to the jumper harness, route the wires
through the opposite connectors C-clip, then clip
the connectors to the harness mounting pin.
5.2.22 Apply and release the brakes. The hub should turn
easily by hand after applying and releasing the brake.
5.2.23 Recheck the running clearance. Readjust if
necessary.
5.2.24 Reinstall the wheel, following the vehicle manual
instructions.

The brake pads and rotor must be maintained within the
recommended wear limits. Failure to monitor wear and
replace the brake pads and rotor when required may
result in diminished brake performance.

CAUTION: When using a hoist to support the air disc
brake, do not attempt to use the pad retainer bar as a
bracing point. It is not designed to support the weight
of the brake. Instead, use a brace (or chain) wrapped
around the entire brake to attach the hoist.
5.3.1 In all cases check that the current hose routing
arrangement does not restrict the full travel of the
caliper before beginning work on the assembly.
5.3.2 Remove the brake pads. (See Section 5.2.)
5.3.3 (See Section 5.4). If the actuator used is a spring
brake, following the manufacturer’s guidelines, cage
the spring. With all air pressure drained from the
system, disconnect the air hoses from the brake
chamber.

Vertical Mounting Bolt Style
Caliper/Carrier Assembly
(Showing Spring Brake Actuator)

Alignment
Bushing

Anchor Plate/
Torque Plate

Alignment
Bushing
Mounting Bolts
(6 total washers not
required)

Figure 41 – Vertical Mount Caliper/Carrier
5.3.4 See Figure 41. Supporting the air disc brake by
necessary means, remove the six (6) mounting
bolts/washers and discard. Note: Bendix strongly
recommends that during reassembly these bolts
are replaced – see your vehicle manufacturer for
replacement hardware. Lift the caliper up off the
anchor plate.
The vertical bolt assembly includes an alignment
bushing. This bushing must be saved for reuse during
reassembly of the brake. The bushing mounts in the
torque plate and maintains the correct alignment of the
brake assembly relative to the rotor.

27

5.3.5 If the brake assembly does not separate from the
anchor plate it may be helpful to install an M16 x 2.0
screw longer than 120 mm at the bushing locations
and tap the end of the bolt with a hammer to free
the brake assembly. Remove the assembly.

Caliper/Carrier
Assembly
(Actuator not
shown)

Axial Mounting Bolt Style

Mounting Bolts
and Washers
(6 sets total)

5.3.6 Disconnect the air hose(s) to the brake chamber.
(See Figure 42). Supporting the air disc brake by
necessary means, remove the six bolts attaching
the brake to the anchor plate and remove the
caliper/carrier assembly from the vehicle.
Note: Bendix strongly recommends that during reassembly
these bolts and washers are replaced. See your vehicle
manufacturer for replacement hardware. Remove the
assembly.

Anchor Plate/
Torque Plate

Reinstallation (Both Styles)

5.3.7 Supporting the air disc brake by necessary means,
attach the brake to the anchor plate using six
(new) bolts. Torque to vehicle manufacturer’s
specifications. If torque values and bolts are not
specified by the vehicle manufacturer, then select
a replacement bolt as shown in Table 4.
5.3.8 Reinstall the air hoses (See Section 5.4.8-9) and
check for leaks.
5.3.9 Inspect and reinstall the pads (See Section 5.2).

28

Figure 42 – Axial Mount Caliper/Carrier

Air Disc Brake Attachment Hardware
Vertical Mount

Fastener & Torque

Service Actuators Shown
Left-Hand Brake
Labeled “B”

Right-Hand Brake
Labeled “A”

Fastener: M16 x 2.0 x 110 mm, Class 12.9. Use the
manufacturer’s recommendations, but if unavailable, use
a phosphate and oil-finish fastener. Bendix strongly
recommends using new fasteners each time.
Washer: None used.

Short
(floating) Pin

Shelf

Shelf

Shear
Sleeve
Washers are not used on
vertical-mounted Bendix®
ADB22X® brakes

Left-Hand Brake Torque Pattern (Viewed from Below)

Torque: Using an alternating torque pattern, as shown in the
figure below, pre-torque to between 40-50 ft-lbf [54-68 Nm], with
a final torque of 229 ft-lbf [310 Nm]. Choose the torque pattern
which provides acceptable caliper slide-ability.
Slide-ability Tips:
• After torquing the second, fourth, and sixth bolt, sliding the
caliper back and forth on the guide pins (without the pads
installed) can help to keep the guide pin bushings aligned
during the torque process.
• After the pads have been installed and the running clearance
set, pumping the service brakes, or cycling the parking
brakes can sometimes improve the alignment of the guide pin
bushings and improve slide-ability.

Right-Hand Brake Torque Pattern (Viewed from Below)

Brake’s short (floating pin) is this side

Brake’s short (floating pin) is this side

Frame Side

ƒ

(view from below)



Shear sleeve above, in this location

„
†‚

Shelf above, in this location

(view from below)

Shelf above, in this location

Axial Mount

Caliper/Carrier
Assembly (showing
service actuator )

Frame Side

„
‚†

ƒ


Shear sleeve above, in this location

Fastener & Torque
Fastener: M20 x 2.5 x 60 mm Class 10.9. Use the manufacturer’s
recommendations, but if unavailable, use a phosphate and oil-finish fastener.
Bendix strongly recommends using new fasteners each time.
Six (6) Mounting
Bolts
and Washers are
Required

Washer: Requires a HARDENED 3 mm (minimum thickness) washer for
each bolt. If the vehicle is using a Bendix manufactured axial anchor plate,
with a thickness of 1.14 in. (29 mm) at the point where these bolts are
inserted, then a bolt with an overall length of 2.36 in. (60 mm) will meet the
requirements. CAUTION: The washer outside diameter must be less than
1.5 in. (37.5 mm).
Torque: Pre-torque to 20-60 ft-lbf [27-81 Nm], with a final torque of
375 ft-lbf [508 Nm].

Torque Pattern
Anchor Plate/
Torque Plate

Any cross-pattern, see the example below:


ƒ

†„
‚

Trailer Torque Plate

Fastener & Torque

Fastener: M20 x 2.5 x L Class 10.9
Length determination:
L = Torque Plate (TP) thickness + Carrier engagement + Washer thickness
Lmin = TP thickness + 24 mm + 3 mm
Lmax = TP thickness + 29 mm + 3 mm

Use the manufacturer’s recommendations.
If unavailable, use phosphate
and an oil-finish fastener:
Pre-Torque: 20-60 ft-lbf [27-81 Nm]
Final Torque: 350-400 ft-lbf [475-542 Nm]

Washer: Requires THROUGH HARDENED 3 mm (minimum thickness) for each bolt.

Table 4 – Torque Plate Fasteners and Torque Recommendations (see manufacturer’s recommendations)
29

5.4

SPRING OR SERVICE BRAKE

5.4.1 CAUTION: Follow all safe maintenance
practices, including those listed on page 2 of
this document. Park the vehicle (by other means
than the foundation brakes) on level ground and
chock the wheels.
5.4.2 U s e t h e s p r i n g b r a k e m a n u f a c t u r e r ’s
recommended safety practices in all cases.
Some spring brake and vehicle manufacturers
permit caging the spring brake while the spring
brake is engaged.
THE FOLLOWING INSTRUCTIONS ARE FOR
BENDIX® BRAND PISTON-STYLE ACTUATORS
5.4.3 With the vehicle on a level surface and the wheels
properly chocked, apply air to release the spring
brakes (parking brakes) by using the dash-mounted
air control valve. Back out the release bolt (See
Figure 43, arrow “D”), using a maximum torque of
26 ft-lbs (35 Nm) to cage the air released spring
force on the pushrod.
A
B
A
D

18/1

Dust Cover

Figure 44 – Dust Cover Removal (Actual Dust Cover
Design May Vary)
THE FOLLOWING INSTRUCTIONS ARE FOR ALL
BENDIX® ACTUATORS
5.4.4

THE FOLLOWING INSTRUCTIONS ARE FOR
BENDIX ® DOUBLE-DIAPHRAGM-STYLE SPRING
BRAKE ACTUATORS
CAUTION: Follow all safe maintenance practices,
including those listed on page 2 of this document.
Park the vehicle (by other means than the foundation
brakes) on level ground and chock the wheels.
This procedure will be made much easier if air pressure
(100 - 120 psi; 6.6 - 8.0 bar) is used to collapse the power
spring by applying air to port “12”, before turning the release
bolt nut with a hand wrench or simply by hand.

Remove the dust cap or weather seal from the keyhole
in the center of the piggyback spring brake chamber
(See Figure 44).

5.4.5 Exhaust the air from the brake chambers by using
the dash-mounted air control valve. With all air
pressure drained from the system, disconnect the
air hoses from the brake chamber. While supporting
the brake chamber in position, remove and discard
the brake chamber mounting nuts (See Figure 43,
arrows marked “B”). Remove the brake chamber.
5.4.6

Remove the release tool assembly from the side
pocket of the adapter base.

5.4.7

Insert the release tool (T-bolt) through the release
tool keyhole and into the pressure plate. Pull on the
release tool to seat it properly in the pressure plate.
Turn the release tool one quarter turn clockwise.

5.4.8

Assemble the release tool washer and nut onto the
release bolt and finger tighten only. If caging is being
done manually – it is recommended that some type of
lubrication be applied to the release bolt threads prior
to tightening to prevent galling or stripping.

5.4.9

To cage the main spring, tighten the release nut
with a hand wrench and ensure the service pushrod
is retracting. Do not over-torque the release tool
assembly. Maximum torque is 35 ft-lb (47.45 Nm).
The maximum releasing torque should not exceed
50 ft-lb (67.8 Nm). If the spring has not previously
been compressed by the use of air, verify that the rotor
is now free to rotate and that the brake is released.

B

Figure 43 – Actuator Spring Caging and Removal

Keyhole

DO NOT USE AN IMPACT WRENCH. AN IMPACT
WRENCH MAY OVER-TORQUE THE RELEASE TOOL
AND CAUSE DAMAGE TO THE PRESSURE PLATE.
5.4.10 To ensure the power spring is fully caged, the
extended release tool length should be fully backed
out. The threaded portion of the release tool will
extend approximately 2.9 inches out of the nut when
fully released.

30

Before releasing the air pressure, check to make sure
that hands, etc. are clear of any moving parts.
5.4.11 Release the air pressure from the emergency/
parking port (port 12) after caging and prior to any
disassembly or removal from the vehicle. Ensure
the air pressure is removed from all air reservoirs
before removing the air hoses or working on the
spring brake.
5.4.12 Record the orientation of the spring brake before
removing it to be sure that the replacement is
installed the same way.
5.4.13 Remove the mounting nuts and hoses.
5.4.14 Reinstallation. Before installing the brake chamber,
the actuator flange (See Figure 45, arrow “C”) must be
cleaned and inspected. Consult the vehicle manual.
The spherical cup in the lever (19) must be greased
with white grease (Part No. 14525 or K021964).
Add grease to the rubber gasket on the chamber.

CAUTION: Do not use brake chambers with seals that
have a thickness less than 0.12 in. (3 mm). Use only
actuators which are recommended by the vehicle
manufacturer.
5.4.16 Install the brake chamber using new self-locking
nuts (EN ISO 10513). Alternately tighten both the
nuts step-by-step up to a final torque of 133 ± 7 ft-lbs
(180 ± 10 Nm). Bendix strongly recommends that
new nuts be used. These self-locking nuts and
lubricant are included in Bendix kit part number
K170438.
5.4.17 Reconnect the air hose(s) and be sure that each
hose is not twisted or in contact with moving vehicle
components. The air hose routing must allow for full
caliper travel. Note that for spring brake service
chambers the ports are indicated by: “11” Service
Brake Port and “12” Spring Brake Port.

CAUTION: Do not use grease containing molybdenum
disulfide.
5.4.15 The seal, as well as the pushrod area, must be
clean and dry.

Figure 46 – Port Designations
Note: Where a new spring brake chamber is being installed,
note that in some cases drain plugs are installed (See
Figure 43, arrows marked “A”). Where drain plugs are
present, after installation, remove whichever plug is at the
lowest position. The selected drain hole must be aligned
downwards (or within ±30°) when installed on the vehicle.
In the case of spring brake chambers, install the pads before
uncaging the spring.

C
Figure 45 – Spring Brake Installation

5.4.18 Before returning the vehicle to service, with the
system pressurized, using a soap solution, check for
air leakage. Minimal leakage in the area around the
diaphragm is permitted (100 SCCM), and a one-inch
bubble in one minute at the hose fitting is acceptable.
If abnormal leakage is detected, the diaphragm must
be replaced, or fitting adjusted, respectively.

31

5.5

TAPPET & BOOT ASSEMBLIES AND
TAPPET INNER SEAL REPLACEMENT

5.5.1 CAUTION: Follow all safe maintenance
practices, including those listed on page 2 of
this document. Park the vehicle (by other means
than the foundation brakes) on level ground and
chock the wheels.
In some cases, the technician will need to remove the caliper
carrier assembly from the vehicle. (See Section 5.3.) Note
that new bolts (available from the vehicle manufacturer)
will be needed for reinstallation.
Important: If the vehicle is equipped with spring brakes,
cage the spring brakes on all axles requiring work.
Consult the vehicle manufacturer’s instructions as
necessary. This procedure may be carried out with
the air disc brake installed on, or removed from, the
vehicle. In cases where the caliper/carrier assembly
is removed from the vehicle, NEW fasteners must be
used and properly torqued during reinstallation. Use
only fasteners approved by the vehicle manufacturer.
Note: This maintenance procedure requires specialized
tools. The full Bendix® air disc brake tool kit – part number
K029164 – includes the complete set of tools required for
all permitted maintenance procedures. Alternately, for
locations where only the tappet and boot replacement
procedures will be performed, the smaller Bendix tool kit –
part number K028829 – will suffice. For guide pin and seal
replacement procedures only, use Bendix kit part number
K029107. The Bendix DVD – part number BW7356 – shows
these procedures.

32

Bendix
Part
No.

Description

T01

Cup

T02

Handle for
Cup

T03

Swivel assembly
(short body, brass
disc, and retaining
spring)

T04

Long Strut

T09

Flange

T15

Fork

T24

Black Nylon Disc

Typical Tool View

Table 5 – Tappet and Boot Replacement Tools

22
Inner Seal

11
Pad
Retainer
13 Tappet
and
Boot Asm

44 Pad Retainer Pin
26
Spring Clip
45
Washer

161
Tappet
Bushing

5.5.4 See Figure 48. Extend the tappets – less than
1.75 in. (44.5 mm) – by turning the shear adapter
(61) clockwise. A screwdriver (callout “B” in
Figure 48 inset) should be used to move the boot
and allow the wedge fork (“A” in Figure 49) to be
inserted.
CAUTION: DO NOT INSERT THE SCREWDRIVER
MORE THAN ¼ INCH. Take care not to damage
the inner sealing face (see arrow “X” in Figure
49). Gouges or grooves will prevent a good seal
and will require that the caliper be replaced.

12
Pad
Assembly