MAINTENANCE MAINTENANCE PROCEDURE BLEEDING AIR FROM HYDRAULIC SYSTEM 4 For details, see “STARTING ENGINE (3-72)“. If it is necessary to refer to the items for starting the engine, moving the machine off, steering, or stopping, see the OPERATION section. 1. Bleeding air from pump 2. Loosen air bleed plug (1) and check that oil oozes out from the air bleeder. 3. If the oil does not ooze out, remove the drain hose from the hydraulic pump case and fill the pump case completely with hydraulic oil through drain port (2). Hold the removed hose firmly, keeping the mouthpiece higher than the oil level in the hydraulic tank so that oil will not spill out of the hose. 4.
After completing the air bleed operation, tighten air bleed plug (1) and install the drain hose. NOTICE If the drain hose is installed first, oil will spurt out from plug hole (1). If the pump is operated without filling the pump case with hydraulic oil, abnormal heat will be generated and this may cause an unexpected damage to the pump. 5. Starting engine Start the engine, referring to “STARTING ENGINE (3-72)“. Run the engine at low idling for 10 minutes after starting, then start operations. 6. Bleeding air from cylinders 7. Run the engine at low idling, and extend and retract each cylinder 4 to 5 times, taking care so that a cylinder may not be brought up to its stroke end.
(Stop the cylinder approx. 100 mm short of its stroke end) 8. Next, operate each cylinder 3 to 4 times to the end of its stroke. 9. Finally, operate each cylinder 4 to 5 times to the end of its stroke to completely remove the air. NOTICE If the engine is run at high speed immediately after startup or a cylinder is pushed up to its stroke end, air taken inside the cylinder may cause damage to the piston packing. 4-43