FSB 213-002

Mack Trucks
Greensboro, NC USA
Field Service Bulletin
Trucks
Date
Group
No.
Release
Page
1.2017
213
002
01
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Exhaust Rocker Compression Brake Piston,
Repair
CHU, CXU, GU, TD
FSB 213-002, Exhaust Rocker Compression Brake
Piston, Repair
(January 2017)
For MACK CHU, CXU, GU, and TD trucks built from 01/01/2007 to present, a repair
procedure and new tools have been created to repair of the exhaust rocker compression
brake pistons. In some instances the exhaust rocker piston cap screw may become loose
and back out causing loss of engine compression, or a mechanical injector Diagnostic
Trouble Code (DTC). This repair will require removal of the exhaust rocker piston, removal of
the exhaust rocker piston cap and internal components for cleaning. Ensure the rocker arm
and exhaust rocker compression brake piston are recorded as a pair during this repair
procedure for proper installation. After cleaning, the internal components are re-installed,
thread locker (LOCTITE 270) is applied to the cap, and the cap is tightened with special
tooling to ensure the proper torque is applied. See the repair parts section for special tooling
part numbers. Follow the repair procedures outlined in this Field Service Bulletin (FSB) to
perform this repair procedure.
Note: This bulletin does not apply to MACK Trucks Australia.
PV729-FSB213-002_M
USA138465580
Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
W2118926
Exhaust Rocker Compression Brake Piston Repair Parts
Item
Description
Part Number
1
Retainer Tool
88800569
2
Assembly Tool
88800564
Page
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
Decommissioning the Truck for Repair
You must read and understand the precautions and guidelines in Service Information,
group 20, "General Safety Practices, Engine" 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 Chock the front wheels..
W7086748
5 Disconnect the cable from the battery’s negative terminal.
W3086747
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
Exhaust Rocker Compression Brake Piston Repair
Note: Do not use air impact tools for any part of this repair procedure.
1 Remove the exhaust rocker compression brake piston from the rocker arm.
Note: Record the rocker arm and the exhaust rocker compression brake piston as a
matched pair for installation purposes.
2 Place the Retainer Tool (part number 88800569) in a vise as shown in the figure below.
Note: Do not secure the tool in the vise at this time.
W2118927
3 Measure the diameter of the exhaust rocker compression brake piston to determine the
appropriate tool opening to be used in this repair procedure.
Note: The exhaust rocker compression brake piston diameter will be dimension (A) 28
mm (1.10 in) or (B) 30 mm (1.18 in).
W2118928
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
4 Position the exhaust rocker compression brake piston in the retainer tool as shown in the
figure below. The appropriate opening sizes are (A) 28 mm (1.10 in) or (B) 30 mm (1.18
in).
Note: Ensure the exhaust rocker compression brake piston protrudes approximately 6.35
mm (0.25 in) above the surface of the tool.
W2118929
5 Secure the exhaust rocker compression brake piston and the retainer tool in the vise.
Note: Apply enough pressure to the jaws of the vise to prevent the exhaust rocker
compression brake piston from rotating inside the tool when torque is applied to the cap.
6 Using Assembly Tool (88800564) and hand tools, remove the cap from the exhaust rocker
compression brake piston housing.
Note: Do not use air impact tools for this repair procedure.
W2118930
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
7 Remove the internal components from the exhaust rocker compression brake piston
housing.
Note: The internal components of exhaust rocker compression brake piston are very
small and could be easily misplaced when the cap is removed.
W2118931
8 Using brake cleaner, clean the internal components and the threads on the cap. Store the
internal components and cap in a secure location for installation.
W2118932
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
9 Using compressed air, blow out the inside of the exhaust rocker compression brake piston
housing as shown.
W2118934
10 Ensure the drain hole in the bottom of the exhaust rocker compression brake piston
housing is clean and clear of any debris.
W2118933
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
11 Install the internal components in the exhaust rocker compression brake piston housing.
W2118935
12 Position the cap in the exhaust rocker compression brake piston housing, then rotate the
cap one full turn until it starts to thread.
Note: Due to pressure from internal spring compression, slight pressure on the cap is
required to ensure the cap turns smoothly in the exhaust rocker compression brake piston
housing.
13 Apply one drop of thread locker (LOCTITE 270) in (4) places (90 degrees from each
other) on the exhaust rocker compression brake piston cap.
W2118936
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
14 Using a hand tool and Assembly Tool (88800564), tighten the cap until it bottoms out in
the exhaust rocker compression brake piston housing.
Note: Use hand tools only, do not use air impact tools.
15 Using a torque wrench with Assembly Tool (88800564) tighten the cap to 30 ± 3 Nm (22 ±
2 ft-lb).
W2118937
16 Remove the exhaust rocker compression brake piston from the retainer tool.
17 Install the exhaust rocker compression brake piston in the rocker arm as previously
recorded.
18 Repeat steps 2 through 17 for the remaining exhaust rocker compression brake pistons
that require repair.
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
002
01
Commissioning the Truck for Operation
1 Connect the battery cable to the negative (ground) terminal.
W3086758
2 Remove the wheel chocks.
W7086759
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Mack Trucks
Field Service Bulletin
Date
1.2017
Group
No.
Release
213
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
Claim Type (used only when uploading from the Dealer
Bus. Sys.)
01
Labor Code
Primary Labor Code (Exhaust Rocker Compression Brake
Piston, Repair), per piston
213-03-09-02
0.2 hrs.
Causal Part
Note: Use the part
number of your exhaust
rocker to file a claim.
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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