I have Hitachi ZX350LC-3 excavator.It works well until few days ago.Firstly I had only problem to rise boom cylinder.After that complete hydraulic works slow.And after that engine fault 1239-1 No pressure to pump(fuel leakage) appeared.I changed fuel filter and electric pump(plastic non-return valve was broken).Fault disappeared,but nothing about hydraulic gets better.I checked hydraulic return filter,oil level,breather,but everything seems OK.I adjusted main relief valve, but nothing changes.Excavators starts with 350 bars on both pumps,but after few moments drops on 60-150 bars maximum,and excavator cant move or operate.Pilot pressure is OK.I cant recognise is this engine,hydraulic or electrical problem.
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