Venting And Priming Hydraulic System - Doosan DX140R Operation & Maintenance Manual

VENTING AND PRIMING
HYDRAULIC SYSTEM
Main System Pump
NOTE: If pump is run without sufficient oil in the main
hydraulic pump, damage can occur. Always vent
pump of air after draining hydraulic system.
1. With the engine stopped, remove vent plug (Figure 130) to
see if any oil is present.
2. If oil is not present, fill pump with oil through port (Figure
130).
3. Install vent plug (Figure 130) first.
4. Start engine and run it for several minutes at low idle
engine speed. This will pressurize the hydraulic oil tank
and system.
5. Slowly loosen vent plug (Figure 130) several turns, until
hydraulic oil flows out of plug. This shows that air has been
released.
6. Tighten the plug (Figure 130).
Hydraulic Cylinders
IMPORTANT
If cylinders are operated in high idle after the hydraulic
system has been drained or the cylinder has been rebuilt,
damage to piston packing and seals can occur. Always vent
air from cylinders at low idle and at a slow speed.
1. Run engine at low idle. Extend and retract each cylinder to
within 100 mm (4 in) of fully stroking it 4 - 5 times.
2. Operate fully extend and retract each cylinder 3- 4 times.
3. Repeat procedure until cylinders extend and retract
smoothly.
DX140R/DX140LCR
Figure 130
Inspection, Maintenance and Adjustment
FG014443
4-81