FSB 511-002

Field Service Bulletin
Trucks
Mack Trucks, Inc.
Greensboro, NC USA
Date
Group
No.
Release
Page
8.2014
511
002
01
1(14)
Brake Drum, Replacement
Steer Axle
CHU, CXU, GU, TD
FSB 511-002, Brake Drum, Replacement (Steer
Axle)
(August 2014)
Some MACK CHU, CXU, GU, and TD trucks built between 08/29/2011 and 06/30/2014,
equipped with a MACK 14.6k steer axle, unitized hub, and 152 mm (6.0 in) wide Bendix brake
shoes can show signs of brake shoe protrusion beyond the brake drum. This condition is
resolved by installing new 152 mm (6.0 in) brake shoes, 178 mm (7.0 in) wide brake drums
(20536276), new dust shields, and replace the existing Z-Brackets.
Note: This Bulletin does not apply to MACK Trucks Australia.
W5092612
Required Parts (Brake Drum, Replacement
Brake Drum Replacement Parts
Item
Description
Part Number
Qty
1
Brake Drum, 178 mm (7.0 in) wide
20536276
2
2
Brake Shoe Kit, 152 mm (6.0 in), Bendix
745-K097965
2
3
Dust Shield, Bendix
22375164
2
4
Z-Bracket, LH
22375312
1
5
Z-Bracket, RH
22375315
1
PV729-FSB511-002_M
USA65646
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
Decommissioning the Truck for Repair
You must read and understand the precautions and guidelines in Service Information,
group 50, "General Safety Practices, Brakes" before performing this procedure. If you are
not properly trained and certified in this procedure, ask your supervisor for training before
you perform it.
NOTE: Information is subject to change without notice. Illustrations are used for reference
only and can differ slightly from the actual vehicle being serviced. However, key
components addressed in this information are represented as accurately as possible.
1 Park the vehicle on a flat and level surface.
2 Apply the parking brake.
3 Place the transmission in neutral or park.
4 Install the wheel chocks.
W7086748
Page
2(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
5 Disconnect the cable from the battery’s negative terminal.
W3086747
Brake Drum, Replacement, Bendix (1.0 hrs)
Note: The right side is shown for instructional purposes.
Note: The Hendrickson axle with a tapered hub is shown. However, the brake drum
replacement procedure for a MACK axle with unitized hub is the same.
1 Lift the steer axle with a jack, place the truck on jack stands, and remove the jack.
2 Remove the wheel nuts.
W5092465
Page
3(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
3 Remove the wheel.
W5092466
4 Remove the four fasteners securing the existing dust Shield.
W5092646
Page
4(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
5 Remove the dust shield.
W5092647
6 Remove the fasteners securing the existing z-bracket.
W5092615
Page
5(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
7 Remove the existing z-bracket.
W5092616
8 Back off of the brake (slack adjuster).
Note: The Gunite slack adjuster is shown in this procedure for backing off the brakes.
However, this procedure is similar for other brands.
W5092617
Page
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Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
9 Remove the brake drum.
Note: Discard the brake drum.
W5092468
10 Remove the brake shoes, brake springs, and rollers.
W5092618
Page
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Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
11 Install the replacement brake shoes, brake springs and rollers.
Note: The brake springs, and rollers are included in the brake shoe kit.
W5092618
12 Install the new z-bracket. See the table on page 1 for the correct part numbers.
W5092619
Page
8(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
13 Install the fasteners securing the z-bracket. See the table on page 1 for the correct part
numbers.
14 Tighten the fasteners to 40 ± 5 Nm (29 ± 3 ft-lb).
W5092620
15 Install new dust shield. See the table on page 1 for the correct part numbers.
W5092621
Page
9(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
16 Install the four fasteners securing the dust shield.
17 Tighten dust shield fasteners to 40 ± 5 Nm (29 ± 3 ft-lb).
W5092622
18 Install the replacement brake drum (178 mm (7.0 in) wide). See the table on page 1 for the
correct part numbers.
W5092468
Page
10(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
19 If applicable, loosen the brake chamber clamp and re-position the clamp at a 45° angle or
until proper clearance of the wheel is obtained. See figure below.
Note: Do not rotate the brake chamber. Rotate the clamp only.
Note: Ensure the brake chamber clamp does not interfere with the dust shield or drum.
20 If applicable, tighten the brake chamber clamp fastener to 44 ± 4 Nm (32 ± 3 ft-lb).
W5092623
21 Install the wheel.
W5092466
Page
11(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
22 Install the wheel nuts.
23 Tighten the wheel nuts to 610 Nm (450 ft-lb).
W5092465
24 Adjust the brake as recommended per (slack adjuster) manufacturer.
Note: The Gunite slack adjuster is shown in this procedure for adjusting the brake.
However, this procedure is similar for other brands.
W5092617
25 Repeat steps 1 through 24 for the left side of the truck.
26 Lift the steer axle with a jack, remove the jack stands, and lower the axle.
27 Go to Commissioning the Truck for Operation.
Page
12(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
Commissioning the Truck for Operation
1 Connect the battery cable to the negative (ground) terminal.
W3086758
2 Remove the wheel chocks.
W7086759
Page
13(14)
Mack Trucks, Inc.
Field Service Bulletin
Date
8.2014
Group
No.
Release
511
002
01
Reimbursement
This repair may be eligible for reimbursement
if a product failure was experienced within
time and mileage limits of the applicable
Warranty coverage. Reimbursement is
obtained via the normal claim handling
process.
UCHP
Reimbursement
eWarranty
Reimbursement
Claim Type (used only when uploading from
the Dealer Bus. Sys.)
01
01
Primary Labor Code (Brake Drum, Replacement)
5112-03-09-01
1.0 hrs.
5126A–01–80
1.0 hrs.
Causal Part
25017906
25017906
Labor Code
MACK Trucks North America reserves the right to make any changes in design or to make
additions to or upon its products without incurring any obligations to install the same on
vehicles previously built.
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