Lull 944E-42 Service Manual - Manual (Page 228)

Engine: Cummins 4BT 3.9, B4.5T and QSB 4.5T
7.26 Model 644E-42/944E-42 Rev. 6/04
7.8.4 Fuel Lift Pump Testing
To test the diaphragm, remove the fuel inlet line (1 or 6)
from the fuel lift pump (2 or 7). Block the fuel inlet with a
finger and operate the hand plunger (3 or 8). A properly
operating pump will provide suction that will remain until
the finger is removed from the inlet.
a. Fuel Lift Pump Removal
1. If the vehicle has dual batteries, disconnect both
negative battery cables (11 and 12) from both
batteries.
To access the lower battery (13), loosen the
knob (14) far enough so that the lip (15) on the upper
battery box clears the knob. Lift up the upper battery
box (16) and swing it out, so that the box clears the
hydraulic tank support bracket, to gain access to the
lower negative battery cable (11). Disconnect the
lower negative battery cable.
2. Clean debris from around the lift pump (2 or 7).
3. Disconnect the fuel inlet line (1 or 6).
4. Remove the capscrews (5 or 10), gasket, and fuel lift
pump (2 or 7).
b. Cleaning and Drying
Clean the exterior of the pump with mineral spirits and
blow dry with compressed air.
Note: Parts replacement is not practical. The fuel lift
pump is serviced as an entire assembly.
c. Fuel Lift Pump Installation
1. Clean the mounting surface on the cylinder block.
2. Install the fuel lift pump (2 or 7) with a new gasket.
Install and torque the capscrews (5 or 10) to 18 lb-ft
(24 Nm).
3. Connect the fuel line (1 or 6). Bleed air from fuel
system (Refer to Section 7.8.6, “Bleeding Air From
The Fuel System,” for proper procedures.)
4. If the vehicle has dual batteries, connect both
negative battery cables (11 and 12) to both
batteries.
Connect the lower negative battery cable (11) to the
negative (-) terminal on the lower battery (13). Swing
the upper battery box (16) in and make sure that the
lip (15) on the upper battery box slides below the
knob (14). Secure in place with the knob (14).
MT2530
1
2
3
4
5
644E-42
MU5450
6
7
8
9
10
944E-42
MU0650
11
12
13
14
15
16