TROUBLESHOOTING
11-4
Hydraulic System
When the machine is stored without operation, air mixed in hydraulic oil will become separated and will accumulate
in the cylinder upper sections, causing a delay in the response time of the machine movement or weak power
development.
In case these symptoms appear, repeatedly operate all actuators several times.
Problem
Cause
Solution
No hydraulic Functions
(Noise from pumps)
Faulty hydraulic pump
* Repair or replace
Lack of hydraulic oil
Refill
Broken suction pipe and/or hose
* Repair or replace
No hydraulic Functions
(Hydraulic pump noise remains
unchanged)
Faulty pilot pump
* Replace
Faulty pilot control shut-off solenoid valve
* Replace
Faulty wire harness (pilot control shut-off
solenoid valve) pilot control shut-off switch
* Repair or replace
The pilot control shut-off lever is in the LOCK
position
Turn the pilot control shut-off
lever to the UNLOCK position
All actuators have no power
Malfunction due to worn hydraulic pump
* Replace
Decreased main relief valve set pressure in the
control valve
* Adjust
Lack of hydraulic oil
Refill
Clogged suction strainer in the hydraulic oil
tank
Clean
Absorption of air from the oil suction side
Retighten
Faulty pressure sensor
* Replace
Faulty solenoid valve
* Replace
Only one side lever is inoperable or has
no power
Faulty relief valve in the control valve
* Repair or replace
Broken pipe and/or hose
* Repair or replace
Loose pipe line joint
Retighten
Broken O-ring at pipe line joint
* Replace
Faulty hydraulic pump
* Repair or replace
Faulty pilot valve
* Replace
Faulty pilot circuit line
* Repair or replace
Faulty pilot solenoid valve
* Repair or replace
Items with * mark: Consult your nearest Hitachi dealer.
Summary of Contents for 090001
Page 4: ......
Page 9: ...CONTENTS Bucket Teeth Transverse Type Pin Used Type 13 18 INDEX 14 1 ...
Page 10: ...CONTENTS MEMO ...
Page 14: ...MACHINE NUMBERS 4 MEMO ...
Page 64: ...MEMO SAFETY SIGNS S 50 ...
Page 198: ...OPERATOR S STATION 1 134 MEMO ...
Page 200: ...BREAK IN 2 2 MEMO ...
Page 212: ...OPERATING THE ENGINE 3 12 MEMO ...
Page 266: ...OPERATING THE MACHINE 5 46 MEMO ...
Page 398: ...MAINTENANCE 7 124 MEMO ...
Page 399: ...8 1 HYDRAULIC CIRCUIT AND ELECTRICAL CIRCUIT Hydraulic Circuit MDAA 08 001 ...
Page 402: ...MAINTENANCE UNDER SPECIAL ENVIRONMENTAL CONDITIONS 9 2 MEMO ...
Page 404: ...STORAGE 10 2 MEMO ...