Lull 944E-42 Service Manual - Manual (Page 231)

7.29 Model 644E-42/944E-42 Rev. 6/04
Engine: Cummins 4BT 3.9, B4.5T and QSB 4.5T
b. Injector Replacement
Preparatory steps:
• Thoroughly clean around the injector(s).
• Disconnect the high-pressure fuel lines (2).
• Disconnect the fuel drain manifold (3).
IMPORTANT: The injector must not rotate in the bore of
the cylinder head or damage to the cylinder head will
occur. If rust has formed on the hold-down nut, soak the
nut with rust-penetrating solvent for a minimum of three
minutes. Then, tap the injector body with a drift pin to
help loosen any rust.
1. Use a 16 mm wrench to prevent the injector body (4)
from turning. Loosen the hold-down nut (5) with a
24 mm box wrench.
2. Clean the injector nozzle bore.
3. Remove the injector hold-down nut from the injector
body.
4. Apply a light coat of anti-seize compound to the new
injector surface. Avoid getting anti-seize compound
into the fuel drain hole.
5. Install the hold-down (5) nut on the injector body.
6. Install a new o-ring into the recessed groove in the
top of the hold-down nut. Make sure the o-ring is not
cut or twisted during installation.
7. Apply a light coat of anti-seize compound to the
threads of the injector hold-down nut (5).
8. Assemble the injector and new copper washer (6).
Use only ONE copper washer. A light coat of clean
15W40 engine oil, placed between the washer and
the injector, will help keep the washer from falling
during installation.
9. Install the injector with the protrusion (7), on the side
of the nozzle fitting, into the notch (8), in the head.
10. Tighten the hold-down nut (5) and torque to 44 lb-ft
(60 Nm).
11. Install the fuel drain manifold (3) and torque to 6 lb-ft
(8 Nm).
12. Install the high-pressure fuel lines (2) and torque to
18 lb-ft (24 Nm).
13. Run the engine and check for fuel and air leakage.
14. Bleed the fuel system. (Refer to Section 7.8.6,
“Bleeding Air From The Fuel System.”)
7.8.8 After Fuel System Service
1. Drain and flush the fuel tank if it was contaminated.
2. Bleed air from the fuel system. (Refer to Section
7.8.6, “Bleeding Air From The Fuel System.”)
3. Fill the fuel tank with fresh, clean diesel fuel as
required.
MT3160
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MA1960
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