42-077

Steer Axle Brake Chatter
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia
122SD and Coronado

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

Freightliner
Service Bulletin

Description of Revision: This bulletin replaces the version dated
10/30/2018. The cause code has been changed in the warranty
table.

General Information
Some New Cascadia vehicles equipped with a Meritor stamped spider steer axle drum brake package have
experienced brake chatter (noise) when the service brakes are applied at lower speeds. Examples of brake
chatter can be heard in the following videos:
ABS Brake Noise https://dtnacontent-dtna.prd.freightliner.com/content/dam/techlit/video/
ABS_Brake%20Noise.mp4
This issue can be resolved by replacing the stamped spider plates with cast plates (part number TDA KIT8341)
using the instructions below.

General Safety Precautions
WARNING
When replacing brake pads, shoes, rotors, or drums, always replace components as an axle set.
• Always reline both sets of brakes on an axle at the same time.
• Always replace both rotors/drums on an axle at the same time.
• Always install the same type of linings/pads or drums/rotors on both axle ends of a single axle at
the same time. Do not mix component types.
Failure to do so could cause uneven braking and loss of vehicle control, resulting in property damage,
personal injury, or death.
When working on or around a vehicle, observe the following precautions:
• Park the vehicle on a level surface and apply the parking brakes. Shut down the engine and chock the
tires.
• If the vehicle is equipped with air brakes, make certain to drain the air pressure from all reservoirs before
beginning any work on the vehicle. Depleting air system pressure may cause the vehicle to roll. Keep
hands away from brake chamber pushrods and slack adjusters, which may apply as air pressure drops.
• Disconnect the batteries.
• Never connect or disconnect a hose or line containing compressed air. It may whip as air escapes. Never
remove a component or pipe plug unless you are certain all system pressure has been released.
• Never exceed recommended air pressure. Always wear safety glasses when working with compressed air.
Never look into air jets or direct them at anyone.
• Do not remove, disassemble, assemble, or install a component until you have read and understand the
service procedures. Some components contain powerful springs, and injury can result if not properly
disassembled. Use the correct tools and observe all precautions pertaining to use of those tools.
• Replacement hardware, tubing, hose, fittings, etc. should be the equivalent size, type, length, and
strength of the original equipment.
• Make sure when replacing tubes or hoses that all of the original supports, clamps, or suspending devices
are installed or replaced.

Freightliner Service Bulletin, 01/08/2019

Page 1

42-077

Steer Axle Brake Chatter

Freightliner
Service Bulletin

FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia
122SD and Coronado

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

• Replace devices that have stripped threads or damaged parts. Repairs requiring machining should not be
attempted.
• Prior to returning the vehicle to service, make certain all components and systems are restored to their
proper operating condition.

Disassembly and Inspection
WARNING
Before working on or around air brake systems and components, review the General Safety
Precautions. Failure to do so may result in personal injury.
When performing these instructions, refer to Fig. 1.

8
22
4

2
9
1

3

7

3

11

15
20

24

5

17

23

16

16

6

21

19

4

15

Anchor Pin
Anchor Pin Bushing
Retaining Spring
Brake Shoe and Lining Assembly
Cam Roller
Roller Retainer
Capscrew, Chamber Bracket
Plug

9. Capscrew, Dust Shield
10. Dust Shield
11. Camshaft Snap Ring
12. Washer (spacer)
13. Automatic Slack Adjuster
14. Washer (thick spacer)
15. Camshaft Grease Seal
16. Camshaft Bushing

14

13

18
7

11/02/2016

1.
2.
3.
4.
5.
6.
7.
8.

12

10

f421684

17. Camshaft-and-Chamber Bracket
18. Grease Fitting
19. Chamber Bracket Seal
20. Return Spring
21. Return Spring Pin
22. Brake Spider
23. Camhead Thrustwasher
24. S-Head Camshaft

Fig. 1, Q Plus Brake (other than MX500 Series)

1. Park the vehicle on a level surface, shut down the engine, and set the parking brake. Chock the tires on the
rear axle.

Page 2

Freightliner Service Bulletin, 01/08/2019

42-077

Steer Axle Brake Chatter
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia
122SD and Coronado

Freightliner
Service Bulletin

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

2. Raise the front axle and place safety stands under the frame or axle. Be sure the stands will support the
weight of the vehicle.
3. Remove the front wheels. For instructions, see Section 40.00, Subject 100 in the New Cascadia Workshop
Manual.
4. Remove the front hubs. For instructions, see Section 33.01 in the New Cascadia Workshop Manual.
5. Remove the brake drums. For instructions, see Section 33.01 in the New Cascadia Workshop Manual.

IMPORTANT: Meritor recommends that the brake drum not be turned or rebored (resurfaced). Turning
or reboring drums can decrease the strength and heat capacity of the drum.
6. Inspect the brake drum, as follows. See Fig. 2.

B

A

11/10/2016

f420690a

A. Check for diameter and out-of-round.
B. Check for cracks, heat checks, glazing, and
grooves.
Fig. 2, Brake Drum Inspection

6.1

Check the drum for cracks. Replace any cracked drum.

6.2

Check the drum for severe heat-checking, heat-spotting, scoring, pitting, distortion, and out-of-round.
Some drums that are glazed, grooved, or out-of-round can be repaired. For detailed instructions, see
Section 33.01 in the New Cascadia Workshop Manual.

6.3

Using a drum caliper or other measuring device, measure the inside diameter of the drum in several
locations. Replace the drum if it exceeds the maximum diameter stamped on it.

7. Disconnect the slack adjuster from the pushrod clevis, as follows. For detailed instructions, see Section
42.11 for Haldex, or Section 42.12 for Meritor automatic slack adjusters in the New Cascadia Workshop
Manual.
7.1

Remove the cotter pin from the clevis pin; remove the clevis pin. See Fig. 3.

Freightliner Service Bulletin, 01/08/2019

Page 3

42-077
Freightliner
Service Bulletin

Steer Axle Brake Chatter
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia
122SD and Coronado

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

2
1

3
5

11/10/2016

4

1. Clevis Pin
2. Clevis
3. Anchor Bracket

f420471b

4. Control Arm
5. Adjusting Hexnut

Fig. 3, Disconnecting Slack Adjuster from Clevis

NOTICE
For a Meritor automatic slack adjuster, disengage the pull-pawl before turning the manual adjusting nut.
Failure to do so could damage the pull-pawl teeth. The brake clearance will not automatically adjust if
the pull-pawl is damaged.
7.2

For a Meritor automatic slack adjuster, disengage the pull-pawl on the side of the adjuster. Using a
screwdriver or an equivalent tool, pry the pawl button out about 1/32 inch (0.8 mm) and wedge the
tool in place. See Fig. 4. Pull-pawls are spring-loaded. When the tool is removed, the pull-pawl will
engage the teeth automatically.

IMPORTANT: Never pull the slack adjuster out of the pushrod clevis. Always turn the adjusting nut
for positioning.
7.3

Using a wrench, turn the manual adjusting nut to back the slack adjuster out of the clevis.
• On Meritor adjustors, turn the square adjusting nut clockwise (as if loosening a right-hand
threaded fastener).
• On Haldex adjusters, turn the adjusting hexnut counterclockwise. You will hear a ratcheting
sound.

8. Remove the slack adjuster, as follows.
8.1

From the slack adjuster side of the camshaft-and-chamber bracket, remove the snap ring and any
washers, spacers, and seals from the camshaft. See Fig. 1.

8.2

Remove the slack adjuster from the camshaft.

Page 4

Freightliner Service Bulletin, 01/08/2019

42-077

Steer Axle Brake Chatter
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia
122SD and Coronado

Freightliner
Service Bulletin

Business Class M2
Cascadia
108SD/114SD
> New Cascadia

11/10/2016

f422461

A. Insert a screwdriver here to pry the pull-pawl out
about 1/32 inch (0.8 mm).
Fig. 4, Meritor ASA Pull-Pawl Disengagement

9. Inspect the slack adjuster for damage or binding, as follows.
9.1

Check the slack adjuster clevis for cracks or bushing wear. Check the splines for chipped teeth and
deformation. Replace as needed.

NOTE: For a Haldex automatic slack adjuster, there is an internal clutch that resists the manual
adjusting nut from being turned in the counterclockwise direction. When checking these slack
adjusters for binding, only rotate the manual adjusting nut in the clockwise direction.
9.2

Using a torque wrench that measures lbf·in (or N·cm), turn the manual adjusting nut clockwise so
that the worm gear rotates a full 360 degrees (typically 22 turns of the wrench).