18SP724 – EPA07 DD15/16 Three-Filter Fuel System
Needle Return Line Service Kit (P/N: A4720708332)
KIT DESCRIPTION
This service kit (P/N: A4720708332) contains all the necessary parts to replace the
Needle Return Fuel line and the M16x1.5 cylinder head fitting on EPA07 DD15/16
engines with the Three-Filter Fuel System.
KIT CONTENTS
Part No.
A4720704032
A4720783831
18SP724

Qty.
1
1
1

Description
Needle Return Line
M16x1.5 Cylinder Head Fitting
Installation Instructions

REPAIR PROCEDURE

Removal of the Needle Return Line – Three-Filter System

PERSONAL INJURY
To avoid injury, never remove any engine component while the
engine is running.
Remove as follows:

NOTICE:
Engine size/model year specific service kits, containing all necessary parts to
replace the high pressure fuel rail feed lines have been released. Refer to TS letter
13 TS-21 for the high pressure fuel line kit numbers to repair these engines.
1. Remove and discard the high pressure fuel rail feed lines. Refer to PSL section
"Removal of the High Pressure Fuel Rail Feed Lines - Three-Filter System".
2. Using J-48836 to hold the cylinder head fitting, remove the needle return line from
the cylinder head fitting using J-48770.
3. Remove the needle return line from the high pressure flange.
4. Remove the needle return line from the needle return pressure control valve.

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5. Using J-48836, remove the needle return line cylinder head fitting from the cylinder
head and discard the sealing washer.

Installation of the Needle Return Line – Three-Filter
System
Install as follows:
NOTE: EPA07 engines have an M18x1.5 and an M16x1.5 cylinder head fitting. EPA10
and newer engines use M18x1.5 only.
1. Using a new sealing washer, install the supplied M16x1.5 cylinder head fitting at the
rear of the cylinder head.
2. Torque the cylinder head fitting to 45 to 50 N·m (33 to 37 lb·ft).
3. Install the needle return line on to the cylinder head fitting, fuel filter module and high
pressure flange.
4. Torque the needle return to the cylinder head fitting to 23 to 25 N·m (17 to 19 lb·ft),
to the fuel filter module to 28 to 30 N·m (21 to 22 lb·ft) and to the high pressure
flange to 25 N·m (18 lb·ft).

PERSONAL INJURY
All parts provided within this kit must be installed in the proper locations,
and MUST be fastened to the specified torque. Failure to properly torque
hardware/components will result in failure of a high pressure fuel feed
line, resulting in possible fire and/or personal injury.

NOTICE:
Engine size/model year specific service kits, containing all necessary parts to
replace the high pressure fuel rail feed lines have been released. Refer to TS letter
13 TS-21 for the high pressure fuel line kit numbers to repair these engines.

5. Install the high pressure fuel rail feed lines. Refer to PSL section "Installation of the
High Pressure Fuel Rail Feed Lines - Three-Filter System”.

Specifications are subject to change without notice. Detroit Diesel Corporation is registered to ISO 9001:2008.
Copyright © Detroit Diesel Corporation. All rights reserved. Detroit™ is a brand of Detroit Diesel Corporation,
a Daimler company.
18SP724 1506 As technical advances continue, specifications will change. Printed in U.S.A.

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