Вот что в книжке Хитачи написано про обслуживание гидравлики, по не русски понимаю плохо , может Вы прочитаете где написано про необходимость фильтровать масло? Книжка называется TTLA-0678ZX Обучение по обслуживанию экскаваторов класса ЯЧ200-ЯЧ330 третьей серии. Это мне так сосед прочитал
D. HYDRAULIC SYSTEM
INSPECTION AND MAINTENANCE OF HYDRAULIC
EQUIPMENT
CAUTION: During operation, the parts of the hydraulic system become very hot. Allow the machine to cool Down before beginning inspection or maintenance.
1. Be sure that the machine is parked on a level, firm surface
before servicing hydraulic equipment.
2. Lower the bucket to the ground and stop the engine.
3. Begin servicing hydraulic components only after components,
hydraulic oil and lubricants are completely cooled,
and after releasing residual pressure.
3.1 Bleed air from the hydraulic oil tank to release internal
pressure.
3.2 Allow the machine to cool down.
Note that servicing heated and pressurized hydraulic
components may cause hot parts and/or oil to fly off or
escape suddenly, possibly resulting in personal injury.
3.3 Keep body parts and face away from plugs or screws
when removing them.
Hydraulic components may be pressurized even when
cooled.
3.4 Never attempt to service or inspect the travel and swing
motor circuits on slopes. They are highly pressurized
due to self-weight.
4. When connecting hydraulic hoses and pipes, take special
care to keep seal surfaces free from dirt and to avoid
damaging them. Keep these precautions in mind:
4.1 Wash hoses, pipes, and the tank interior with a washing
liquid and thoroughly wipe it out before reconnecting
them.
4.2 Only use O-rings that are free of damage or defects. Be
careful not to damage them during reassembly.
4.3 Do not allow high pressure hoses to twist when connecting
them. The life of twisted hoses will be shortened
considerably.
4.4 Carefully tighten low pressure hose clamps.
Do not overtighten them.
5. When adding hydraulic oil, always use the same brand of
oil; do not mix brands of oil. As the machine is filled with
Super EX 46HN when it is shipped from the factory, use
it as a general rule. When selecting to use another brand
of oil listed in the table “Brand names of recommended
hydraulic oil”, be sure to completely replace the oil in the
system.
6. Do not use hydraulic oils other than those listed in the
table “Brand names of recommended hydraulic oil”.
7. Never run the engine without oil in the hydraulic oil tank.
И вот еще написано
2 Change Hydraulic Oil
3 Suction Filter Cleaning
--- every 5000 hours, 2500 hours
or 1500 hours
CAUTION: Hydraulic oil may be hot. Wait for oil to
cool before starting work.
IMPORTANT: Hydraulic oil changing intervals differ according
to kind of hydraulic oils used. (See
Recommended Oil Chart in this group)
1. Park the machine on a level surface with the upperstructure
rotated 90° for easier access.
2. Position the machine with the arm cylinder fully retracted
and the bucket cylinder fully extended.
3. Lower the bucket to the ground.
4. Turn the auto-idle switch off.
IMPORTANT: The turbocharger may be damaged if the
engine is not properly shut down.
5. Run the engine at slow idle speed without load for five
minutes.
6. Stop the engine. Remove the key from the key switch.
7. Pull the pilot control shut-off lever to the LOCK position.
8. Clean the top of the hydraulic oil tank to keep dirt out of
the hydraulic system.
CAUTION: The hydraulic oil tank is pressurized. Push
the pressure release button on the air breather before
removing the air breather.
9. Push pressure release button (1) on the air breather.
10. Remove cover (2).
11. Remove oil using a suction pump. The hydraulic oil tank
capacity, up to specified oil level, is approximately A.
12. Remove drain plug (3). Allow oil to drain.
13. Remove suction filter and rod assembly (4).
14. Clean the filter and tank interior. If the filter is to be replaced,
install new filter on the rod as shown. Tighten nut
to 14.5 to 19.5 N•m (1.5 to 2.0 kgf•m, 11.0 to 14.5 lbf•ft).
Model A
ZX200-3, 270-3, 330-3 Class 869 mm (34.2 in)
15. Install filter and rod assembly (4). Make sure the filter is
positioned correctly on the outlet.
16. Replace the hydraulic tank oil filter. (See “Maintenance
Every 500 Hours” Section)
17. Clean, install and tighten drain plug (3).
18. Add oil until it is between the marks on the oil level
gauge.
19. Install cover (2). Make sure filter and rod assembly (4) are
in correct positions. Tighten the bolts to 49 N•m (5 kgf•m,
36 lbf•ft).
20. Be sure to bleed air form the system following the procedures
shown next page.
Тут еще несколько картинок нарисованно, но я не буду их срисовывать, они по русски нарисованы и машинки для промывки и фильтрации из бочки нет. Поверьте на слово пожалуйста.
Ну вот как то так. Не привилась у япнских хитачевцев пока Ваша культура обслуживания гидравлики, вот и ломается поэтому, иногда, может быть, наверое. Но им к чему стремиться
