FSB-512-002

SB-10054072-4580
Field Service Bulletin
Trucks
Volvo Trucks North America
Greensboro, NC USA
Date
This Field Service Bulletin replaces FSB 512-001 dated 11.13.
11.13
Group
No.
Release
512 002 01
Page
1(17)
Thermal Overload, Air Disc Brakes
VAH, VHD, VN
FSB 512-002, Thermal Overload, Air Disc Brakes
(November 2013)
It has been reported in the field that the Bendix air disc brake may exhibit a thermal overload
condition. Thermal overload is simply an over adjustment of the normal pad wear
compensation that maintains the running clearance between the brake pad and rotor.
Thermal overload reduces the running clearance between the pad and rotor below a desired
level. This over adjustment does not come on suddenly, but rather slowly over time, until the
running clearance goes to zero and the pads are in contact with the rotor. Under this condition
the pads swell and may drag until the high temperature (accelerated) wear removes enough
pad material to reestablish running clearance. The main causal issue is high frequency or
magnitude of axle vibration and why it is typically only seen at one wheel end.
There have been very limited occurrences of thermal overload across varying applications
and vehicle configurations. However, in the event that any of the above issues are found, or
any thermal overload is suspected, immediately go to the on-line document library at www.
bendix.com for free downloads of Service Data Sheets (SD-23-7541). BW7514b will provide
specific instructions regarding how to diagnose a potential thermal overload occurrence. You
can also contact the Bendix Technical Help Line: 1-800-AIR-BRAKE, (1-800-247-2725) and
select option 2, then option 1, Mon.- Fri., 8 a.m. - 6 p.m. EST. for information on how to
remedy these issues.
Bendix Document Number and Description
•
•
BW7514 – Thermal Overload Checklist
SD-23-7541 – AIR DISC BRAKE ADB22X AND ADB22X-V
Bendix Contact Info
•
•
•
Website: www.bendix.com
Tech team phone number: 1-800-AIR-BRAKE
Tech team e-mail: [email protected]
Service personnel: Please circulate, read and initial
Service
Manager
Warranty
Administrator
PV729-FSB512-002_V
Workshop
Foreman
Service Technicians
USA62575
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
Part Numbers
•
•
•
85136663 — Disc Brake Caliper Assembly LHS
85136662 — Disc Brake Caliper Assembly RHS
85136940 — Brake Shoes
Caliper Fasteners
Steer Axle
Drive Axle
Highway
Refuse
Washer
994875
994875
Bolt
992475
992935
Washer
994875
994875
Bolt
992475
993339 (Ridewell
Quantity 5 and HN
Quantity 6)
993337 (Ridewell
Quantity 1)
Page
2(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
Inspection Procedure
Inspect Vehicle (Thermal Overload Event)
1 Secure the vehicle for service by parking it on a level surface, applying the parking brake,
blocking the wheels, and placing the transmission in neutral or park.
2 Disconnect all cables from the negative (ground) battery terminals to prevent personal
injury from electrical shock and prevent damage to electrical components.
3 Follow safe lifting guidelines, lift and support both the frame and the axle housing.
DANGER
Failure to properly support the front of the axle housing may result in the axle rolling
forward, causing serious injury or death.
4 Remove the wheel/tire assemblies.
5 Release the parking brake.
6 Retrieve instructions for inspection by accessing Bendix website at bendix.com.
7 Perform a search for the words “Thermal Overload”.
8 Click “more” on the Bendix Commercial Vehicle Systems, BW7514 THERMAL
OVERLOAD CHECKLIST Download.
9 Download the latest BW7514 THERMAL OVERLOAD CHECKLIST.
10 Perform steps in the checklist.
11 Replace as needed.
Page
3(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
Brake Pad Replacement
1 Chock the wheels.
2 Lift and support the axle on jack stands.
3 Release the parking brakes.
4 Remove the wheel/tire assembly(s) from the wheel end(s) in question.
5 Back off the brake adjuster.
6 Remove the brake pad retainer, pin and clip.
W5084508
1 Retainer
2 Pin
3 Clip
4 Washer
Page
4(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
7 Remove the brake pads.
Note: Ensure the rest of the brake assembly is operational and within serviceable limits.
W5084510
1 Pad removal
Page
5(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
8 If wear sensors are used, ensure they are serviceable or replace as needed. The adjuster
may need to be turned counter-clockwise to open up enough room between the caliper
and rotor to install the pads. Clean the brake pad contact area on caliper. Install new brake
pads.
W5084526
1 Pads installed
Page
6(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
9 Secure pads with retainer, pin, washer and clip.
W5084527
1 Retainer
2 Pin
3 Clip
4 Washer
10 Adjust the brake pad clearance by turning the adjuster screw until the clearance between
the tappets and pads is between 0.5 mm (0.020 in.) and 1.0 mm (0.040 in.).
Note: The caliper should be pushed inboard on its guide pins during this check.
11 Repeat the above steps for the other wheel end of the same axle.
Page
7(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
12 Install wheel/tire assembly(s). Torque wheel nuts to 610 Nm (450 ft-lb).
W5084816
13 Apply the parking brake.
14 Lift the axle, remove the jack stands and chocks. Lower vehicle.
Page
8(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
Caliper Removal
1 Chock the wheels.
2 Lift and support the axle on jack stands.
3 Release the parking brakes.
4 Remove the wheel/tire assembly(s) from the wheel end(s) in question.
W5084810
Page
9(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
5 Back off the brake adjuster.
6 Remove the brake pad retainer, pin and clip.
W5084508
1 Retainer
2 Pin
3 Clip
4 Washer
Group
No.
Release
512
002
01
Page
10(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
7 Remove the brake pads.
Note: Ensure the rest of the brake assembly is operational and within serviceable limits.
W5084510
1 Pad removal
8 Release parking brakes and cage brake chamber (if applicable).
9 Remove the brake hose.
Page
11(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
10 Remove the actuator assembly - service brake chamber or park brake chamber.
Note: Brake chamber mounting hardware can be reused.
W5084511
1 Actuator Assembly (Park Brake Chamber)
2 Fasteners
Page
12(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
11 Remove the outer boot clips or cap.
WARNING
Never insert fingers between caliper and carrier. Hold the exterior of caliper only, or
serious personal injury may result.
12 Remove the caliper bolts and discard. Use new caliper mounting hardware.
W4084963
1 Bolts
2 Washers
3 Caliper
13 Remove lower fasteners on suspension (if applicable) to access caliper bolts.
14 Remove upper fasteners (if applicable).
15 Remove bracket (if applicable).
Page
13(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
Caliper Installation
1 Install caliper to carrier with new hardware and tighten M20 bolts to 508 Nm (375 ft-lb) for
Highway brake or 271 Nm + 60 degrees (200 ft-lb + 60 degrees) for Refuse brake.
Note: Check caliper hardware part numbers to ensure correct installation of new
caliper (refer to table on page 2).
W5084524
1 Fastener
2 Caliper
2 Check caliper after mounting to carrier: Ensure caliper slides easily on carrier and check
inner boot position on caliper bolt sleeves.
3 Install rubber boots and clips.
Note: Replace rubber boots and clips if necessary.
4 If wear sensors are used, ensure they are serviceable or replace as needed. The adjuster
may need to be turned counter-clockwise to open up enough room between the caliper
and rotor to install the pads. Clean the brake pad contact area on caliper.
5 Install new brake pads and secure retainer, pin, washer and clip. Torque to 27 ±3 Nm (20
±2 ft-lb).
Page
14(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
6 Install the actuator assembly - service brake chamber or park brake chamber. Torque to
180 ±30 Nm (133 ±22 ft-lb).
Note: Brake chamber mounting hardware can be reused.
W5084525
1 Actuator Assembly (Park Brake Chamber)
2 Fastener
7 If spring brake chamber was installed, un-cage park brake chamber at this time.
8 Install brake hose.
9 Adjust the brake pad clearance by turning the adjuster screw until the clearance between
the tappets and pads is between 0.5 mm (0.020 in.) and 1.0 mm (0.040 in.).
Note: The caliper should be pushed inboard on its guide pins during this check.
Page
15(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
10 Install wheel/tire assembly(s). Torque wheel nuts to 610 Nm (450 ft-lb).
W5084816
11 Apply the parking brake.
12 Lift the axle, remove the jack stands and chocks. Lower vehicle.
Page
16(17)
Volvo Trucks North America
Field Service Bulletin
Date
11.13
Group
No.
Release
512
002
01
Rotor Inspection
Refer to Bendix Service Data Sheet SD-23-7541 for rotor inspection.
•
Use wire brush to thoroughly remove all orange discoloration from all rotor surfaces to
prevent future misdiagnosis of the wheel end.
•
If thorough inspection indicates rotor must be replaced, replace per instructions in Bendix
Service Data Sheet SD-23-7541.
Note: If rotor replacement is required, use part number 21538404.
Page
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