EP Equipment CQD16, Service Manual

Page: 99 / 251

85
REV. 07/2016
HYDRAULIC SYSTEM
7
7.7 Gear Pump
Oil Outlet
Oil Inlet
7.7.2 Faults and Causes
1
Fault
Gear pump does not absorb oil or
of small
fl ow
Cause
a. Insuf fi cient hydraulic oil;
b. Pump body defects;
c. Poor sealing with leakage;
d. Oil
fi lter clogging;
e. Oil temperature is too high.
2
Fault
Insuf fi cient gear pump output
pressure
Cause
a. Pump body defects;
b. Pump body with cracks or leaks;
c. Impurities in the pump, oil
fi lter
clogging;
d. Low viscosity of hydraulic oil;
e. Oil temperature is too high;
f. Pressure of relief valve adjusted
too low or adjustment failure.
3
Fault Too much vibration and noise
Cause
a. Pump body defects;
b. Gear pump inlet tubing diameter
is too small;
c. Oil
fi lter clogging, or motor
speed is too high;
d. Motor and oil pump shaft
misalignment.
7.7.1 Removal and Installation
See Section 7.2.1 .
4
Fault Oil leaks
Cause
a. Pump body defects;
b. Seal skeleton spring off;
c. Shaft sealing surface scratched.
5
Fault
Pump is not functioning properly or
blocked
Cause
a. Pump body defects;
b. Pressure valve malfunction;
c. Poor alignment of pump and
motor coupling;
d. Impurities in the pump.
Checking
-
-
Check the pump body for leakage and dama-
ge;
Check if the connection of pump and motor
is normal, if oil inlet / outlet is connected
reversely.
7.7.3 Checking and Testing
If the gear pump is found with failure, it is re-
commended to replace the gear pump directly.
CAUTION