NHTSA ID Number: 10191597
Manufacturer Communication Number: SD-23-7541
TSB/Document Date: 2021-05-04
Summary
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.
13
Tappet
and Boot
Assembly
61
Shear
Adapter
13
T15
A
22
161
Tappet
Bushing
22 Inner Seal
6 Adjuster
Cap
Figure 47 – ADB Exploded and Section Views
5.5.2 Pad Removal: follow Sections 5.2.1-5.2.11 for
removal of the brake pads.
5.5.3 Inspect the Brake Rotor. (See Section 4.4)
Tappet and Boot Assembly (13) Removal
CAUTION: NEVER EXTEND THE TAPPET MORE
THAN 1.75 in. (44.5 mm). See Figure 48. Overextending the tappet will result in the tappet losing
engagement with the threads of the synchronizing
mechanism. Since the mechanism can only be set at
the manufacturing plant, the caliper/carrier assembly
must be replaced if this happens.
B
13
X
13
161
Figure 49 – Wedge Tool Use
5.5.5 The tappet and boot assemblies (13) can then be
removed from the threaded tubes (16) by using the
wedge fork (T15). Be sure to orient the wedge tool
with the tapered side towards the tappet.
5.5.6 Remove the old tappet bushings (161).
5.5.7 Retract the threaded tubes by turning the shear
adapter (61) counterclockwise.
5.5.8 See Figure 50. Carefully remove the inner seal
using one or two flat-blade screwdrivers as shown.
Caution: Do not insert the screwdrivers so far that
they come into contact with the threaded tubes.
Damage to the threaded tubes would require that
the brake be replaced.
13
Extend Less
Than 1.75 in.
(44.5 mm)
Figure 48 – Permitted Tappet Extension
33
12
16
22
A
46
16
Figure 50 – Inner Seal Removal
Figure 51 – Use of a New Brake Pad as a Spacer
5.5.9 Inspect the inner sealing face for damage. If
damage is found that would cause the inner seals
not to be able to seal properly, the caliper/carrier
assembly must be replaced. Clean the area around
the inner seal.
5.5.10 Inspect the threaded tubes (16). See Figures 51
and 52. Extend the tubes, but by less than 1.75 in.
(44.5 mm), by turning the shear adapter (61)
clockwise. Inspect the threads for rust, corrosion, or
damage etc. If there is evidence of damage to the
threads, significant rust, or corrosion, the caliper/
carrier assembly must be replaced.
If the technician is working with the caliper on the
vehicle, the technician may place a new brake pad
(12) into the outboard gap to help avoid the loss
of thread engagement of the threaded tubes. (See
Figure 51.)
If the work is being carried out at a workbench, the
technician may insert a 2.76 in. (70 mm) spacer
(See callout “E” in Figure 52) into the caliper (1) to
help avoid the loss of thread engagement.
5.5.11 For threads that are in good condition, grease the
threads with white grease (Part No. 14525 or
K021964). Before installing the replacement inner
seals (22), retract the threaded tubes by turning the
shear adapter (61) counterclockwise.
Note: If the shear adapter fails while you are retracting the
threaded tubes, you may try again with another (new)
shear adapter. If this also fails, this indicates that
the adjuster mechanism is damaged and the caliper
must be replaced.
34
2.76 in.
(70 mm)
16
E
1
Figure 52 – Use of a Spacer (off-vehicle inspection)
To install inner seals where the caliper is on the vehicle:
5.5.12 Position the replacement inner seal (22) over the
threaded tube (16). See Figures 53 and 54 for the
tools and installation arrangement used. Position
the L1 (T03 + T09) with the short spacer (T03) in
position as shown in Figure 54. Guide the tool over
the end of the threaded tube (16). Install the new
inner seal (22) into position by rotating the adjuster
nut on the T03 portion of the tool, using an openended wrench.
T09
T09
T03
Figure 53 – On-Vehicle Inner Seal Tool (L1)
T04
T03
Figure 55 – On-Vehicle Inner Seal Installation Tool (L2)
L1
L2
22
X
16
T09
16
X
L2
22
Figure 54 – On-Vehicle Inner Seal Installation
Figure 56 – Off-Vehicle Inner Seal Installation
To install inner seals where the caliper has been
removed from the vehicle:
5.5.15 Install the new tappet bushing (161) onto the center
post of each threaded tube (16) by hand. By hand,
ease the tappet bushings onto the center post of
the threaded tubes and they will snap into position.
5.5.13 Position the replacement inner seal (22) over the
threaded tube (16). See Figures 55 and 56 for
the tools and installation arrangement used. The
threaded tubes need to be retracted to allow the tool
to be inserted. Use the combination tool L2 (T04 +
T03 + T09) with the long spacer (T04) as shown in
Figure 56. Since the installation tool is guided by
the center post of the threaded tube, advance the
tube a small amount to align the tool and the center
post. Install the new inner seal (22) into position by
rotating the adjuster nut on the T04 portion of the
tool using an open-ended wrench.
CAUTION: To confirm that the inner seal has been
correctly installed, begin to extend the threaded tubes
(16) by turning the shear adapter clockwise by 4-5
turns. Watch as the threaded tube extends. Inner seals
that are installed correctly WILL NOT ROTATE as the
threaded tube extends.
5.5.16 The sealing seat in the caliper for tappet and boot
assemblies (13) must be clean and free of grease.
Wipe the opening with a clean shop rag. Place a
tappet and boot assembly (13) in position over the
center post and tappet bushing.
To install tappet and boot assemblies where the caliper
is on the vehicle:
5.5.17 See Figures 57, 58, and 59. Use tool B1,
comprising tools T01, T02, and T03 to press the
boot into position. The tool is then reversed, and
the nylon disc (T24) is inserted into the T01 “cup”
(combination tool ‘B2’). Holding the T02 handle,
turn the nut on the T03 tool to fully install the tappet
onto the tappet bushing (161).
5.5.14 Note: Inspect the tappet/boot kit to determine if the
tappets supplied are already pre-greased (a plastic
cover should be present — be sure to remove the
cover when installing the tappet). Only in the case
of kits that are not pre-greased will the installer
need to apply grease to the tappets. In all cases,
the threaded portion of the tubes will need to be
greased. Retract the threaded tubes.
35
Figure 57 – On-Vehicle Tappet and Boot Installation
Tool (B1 - with T24 Installed, B2)
13
B1
Figure 60 – Off-Vehicle Tappet Boot Installation Tool
(B3, with T24 Installed, B4)
B3
13
161
Figure 58 – On-Vehicle Tappet Boot Installation
13
Figure 61 – Off-Vehicle Tappet Boot Installation
B2
13
B4
Figure 59 – On-Vehicle Tappet Installation
To install tappet and boot assemblies where the caliper
is removed from the vehicle:
5.5.18 See Figures 60, 61, and 62. Retract the tappets,
as needed, in order to have room to install the
tappets. Use tool B3, comprising tools T01, T02,
and T03 to press the boot into position. The tool is
then reversed, and the nylon disc (T24) is inserted
into the T01 “cup” (combination tool ‘B4’). Holding
the T02 handle, turn the nut on the T03 tool to fully
seat the tappet onto the tappet bushing (161).
36
Figure 62 – Off-Vehicle Tappet Installation
5.5.19 Check that the tappets are firmly attached to the
bushings by gripping and pulling lightly on them by
hand. Confirm that the tappets are able to rotate a
small amount on the tappet bushings by grasping
and turning them by hand. Finally, using a box-end
wrench on the shear adapter, extend the threaded
tubes outward, and check that the boots are held
in place. Retract the tappets.
5.5.20 Reinstall the caliper/carrier assembly, if it was
removed from the vehicle (See Section 5.3).
5.5.21 Reinstall the brake pads (See Section 5.2).
Vertical
Bolt Style
(with
bushing).
Bushing
(6)
Guide Pin (Short)
(4)
Caliper Bolt
(Short)
(39)
Cap
(Large)
(68)
Inner
Boot
(9)
Ring
(58)
Horizontal
Mounting Bolt
Style Shown:
See Inset
Above for
Vertical Bolt
Style (with
bushing).
Shear
Adapter
(61)
Adjuster Cap
(Two alternate
caps supplied
in kit)
(37)
Ring
(58)
Guide Pin
(Long) (5)
Guide
Bushing
(Long) (7)
Caliper
Bolt (Long)
(40)
Cap (Small)
(10)
Inner
Boot
(9)
KIT CONTENTS
Item Description . . . . . . . . . . . . . . . . . . . . Quantity
4
Guide Pin (Short). . . . . . . . . . . . . . . . . . . . . 1
5
Guide Pin (Long) . . . . . . . . . . . . . . . . . . . . . 1
6
Bushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
7
Guide Bushing (Long) . . . . . . . . . . . . . . . . . 1
9
Inner Boot . . . . . . . . . . . . . . . . . . . . . . . . . . 2
10
Cap (Small) . . . . . . . . . . . . . . . . . . . . . . . . . 1
37
Adjuster Cap (Two versions supplied) . . . . . 2
39
Caliper Bolt (Short) . . . . . . . . . . . . . . . . . . . 1
40
Caliper Bolt (Long). . . . . . . . . . . . . . . . . . . . 1
58
Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
61
Shear Adapter. . . . . . . . . . . . . . . . . . . . . . . 1
68
Cap (Large) . . . . . . . . . . . . . . . . . . . . . . . . . 1
(White grease is also supplied - not shown)
Figure 63 – Guide Pin Exploded View
5.6 GUIDE PIN AND BOOT ASSEMBLIES
The Bendix DVD (BW7356) shows this procedure.
5.6.1 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.
Important: If the vehicle is equipped with spring brakes,
cage the spring brakes on all axles to be worked on.
Consult the vehicle manufacturer’s instructions as
necessary. For Bendix® brand piston-style spring brake
chambers, see Section 5.4.
These procedures are typically carried out with the
caliper/carrier removed from the vehicle (may be
carried out with the air disc brake installed). 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 tools needed for the guide pin and
boot installation. See Table 6.
Note that a smaller Bendix tool kit – part number
K029107 – may be used where only the guide pins will be
serviced.
37
Bendix
Part No.
Description
Bendix
Part No.
Description
T05
1-3/8 in.
diameter disc
T14
Brass nut
T06
1-1/2 in.
diameter disc
T16
Dimpling tool
T07
2 in.
diameter sleeve
T20
8 in. bolt
T08
2-1/8 in.
diameter disc
T21
Half sleeve
T10
8 in.
bolt
T26
Cap
installation tool
T12
3-7/8 in.
long sleeve
T27
Cap
installation tool
T13
10 in.
bolt
Typical Tool View
Typical Tool View
Table 6 – Bendix ® ADB22X®, ADB22X® -V and
ADB22X® -LT Air Disc Brake Guide Pin and Seals
Replacement Tools (a washer is also included)
5.6.2 Remove the wheel. Refer to the vehicle manufacturer’s recommendations.
5.6.3 Remove the brake pads. See Section 5.2.
5.6.4 In most cases, the actuator should be removed. See
Section 5.4. In the case of spring brake actuators,
they should be caged before removing the brake
assembly.
5.6.5 In nearly all cases, the air disc brake caliper/carrier
will need to be removed from the vehicle in order to
complete this procedure. See Section 5.3.
Figure 64 – Punch
Guide Pin Cap (10)
Figure 65 – Guide Pin
Cap (10) Hole
5.6.6 Place the brake on a workbench and, using a vice,
secure it by the carrier.
5.6.7 Use a small chisel or similar tool to punch a hole
close to the center of the guide pin cap (10) of the
short guide pin, taking care to only insert the chisel
a small amount. Using the hole just made, pry the
cap off and discard. See Figures 64-66.
38
Figure 66 – Pry to Remove Figure 67 – Use a Small
Chisel to Remove the
Guide Pin Cap (10)
Guide Pin Cap (68)
5.6.8 Remove the other cap (68) that covers the long
guide pin, by using a small chisel and hammer to
apply light blows to the cap, with the chisel aimed
away from the casting. See Figure 67. Discard
both caps.
5.6.9 Using a 14 mm hex
bit socket, remove
and discard the two
caliper bolts (39) and
(40). See Figure 68.
By hand, retract both
guide pins slightly,
and then remove
the caliper from the Figure 68 – Remove the
Caliper Bolts
carrier.
The guide pins are now only held by the retaining
rings (58).
5.6.10 Remove the boot
retaining rings (58)
and the guide pins
(39) and (40). Use
a screwdriver to pry
out the inner boots
(9). See Figure 69.
Discard the removed
Figure 69 – Remove the
items.
Retaining Rings, Guide
Pins, and Boots
5.6.14 Turning the bolt at
the top, draw the
brass nut up, bring
the brass bushing
up and out of the
channel. Discard the
bushing.
Figure 72 – Remove the
Long Guide Pin
Caution: K
eep the removal tool exactly aligned with
the guide pin channel to permit the bushing
to be removed. See Figure 73.
T12
Bushing (10)
Removed
T13
Bushing
(10)
Installed
5.6.11 Clean the caliper upper and lower surfaces around
the bushings.
T14
Grease the bolt prior to each use
Above: Incorrect
Alignment
Above: Correct
Alignment
Figure 73 – Keep the Correct Alignment
Washer
T12
T13
T14
Figure 70 – Brass Bushing Removal Tool
5.6.12 Prepare to remove the brass bushing used in the
long guide pin side. Assemble the long bolt (T13),
washer, and sleeve (T12) as in Figures 70 and 71.
5.6.13 A p p l y g r e a s e t o
the bolt and – after
- 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...
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TSB/Document ID: SD-23-7541
Replacement Service Bulletin Number:
MFR Communication Date: 2021-04-22
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: SERVICE BRAKES, AIR
MFR Component System:
MFR Component Subsystem:
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