Lull 1044C-54 Series II Service Manual - Manual (Page 113)

Supply, Pressure, and Return Hydraulics
31200079 5-31
(Ref. Fig. 5-21) The hydraulic pump is located on the transmission towards
the back of the machine.The hydraulic pump used is a two-section gear
type, driven directly from the transmission power takeoff.
PUMP SPECIFICATIONS:
Type - Gear
Sections - Two
Manufacturer - Vickers
Model - G2020
GPM - 18 at 2500 RPM (Cover End - Pump 1)
GPM - 26 at 2500 RPM (Shaft End - Pump 2)
Troubleshooting Pump Problems
Problem Probable Cause Solution
1. Excessive pump noise A. Low oil level in the hydraulic
reservoir
Fill reservoir to proper level with the recommended
hydraulic fluid. DO NOT overfill.
B. Air in the system 1. Operate hydraulic system until purged.
2. Check inlet (suction) lines and fittings for air
leaks.
C. Vacuum condition 1. Check inlet (suction) lines and fittings for
restrictions.
2. Check reservoir breather filter conditions.
D. Oil too thick Be certain correct type of oil is used for refilling or
adding to the system. Viscosity must be correct for
ambient temperatures.
E. Cold weather Run hydraulic system until unit is warm to the
touch and noise disappears. Check oil viscosity.
2. Pump Overheating A. Internal leakage Return vehicle to maintenance shop for evaluation
and repair.
B. Low fluid level Add oil to operating level.
3. System not developing
pressure
A. Relief valve open Replace or repair the relief valve.
B. Loss of fluid internally
(slippage)
Return the vehicle to the maintenance shop for
repair of hydraulic system.