Sakai SV400D-2, Руководство по ремонту

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HYDRAULIC SYSTEM TROUBLESHOOTING
3. HYDRAULIC SYSTEM TROUBLESHOOTING
3-1. When Performing Hydraulic System Troubleshooting
The largest factor in the majority of failures of hydraulic devices operating under conditions of
higher pressure and greater precision is the entry of dirt (foreign substances) into the hydraulic
circuit. Particular caution is required when supplying hydraulic oil or when disassembling and
assembling hydraulic devices.
1) Pay attention to the work environment.
As much as possible, avoid performing tasks such as supplying hydraulic oil, replacing filters
and repair work on rainy days, when there is strong wind, or in locations where there is much
dust.
2) Disassembly and maintenance work in the field
There is the danger of dust entry when disassembly and maintenance work for hydraulic
devices is performed in the field. In addition, because performance verification after repairs are
completed is difficult, replacement of the entire assembly is preferred. Perform disassembly
and maintenance of hydraulic devices in a special room protected from dust, and use special
testers to verify the performance.
3) Sealing of openings
Use caps, tape, plastic bags or other means to seal the openings of removed pipes and
devices in order to prevent foreign substances from entering. Never leave the openings
exposed or put a shop cloth into them. There is the danger of foreign substances entering or
of leaking oil causing environmental contamination. Do not dispose of waste oil on-site. Either
deliver it to the customer and request disposal or take it back with you and dispose of it.
4) Prevent entry of foreign substances when supplying oil.
Take care that foreign substances do not enter when supplying hydraulic oil. Clean the oil
supply port and the area around it, as well as the supply pump, oilcan and other items. A more
reliable method is to use oil cleaning equipment, which can filter out the contamination that
occurred during storage.
5) Change hydraulic oil while the temperature is still high.
All oils, including hydraulic oil, are softer and flow more readily when they are warm. Higher
temperatures also make it easier to eject the sludge and other substances outside the
circuit together with the oil. For these reasons, oil changes should be performed while the oil
temperature is high. When changing the oil, it is necessary to drain out as much of the old
hydraulic oil as possible. (In addition to the hydraulic oil tank, also drain the oil from the filter
and circuit drain plugs.) If old hydraulic oil remains in the system, the contaminants and sludge
in the old oil will mix with the new oil and shorten the hydraulic oil lifetime.
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