All movements of the excavator cannot move
Main reasons:
(1) Serious shortage of hydraulic oil
(2) Security lock cannot be released
(3) Pilot pump failure, coupling damage, pump shaft fracture diagnosis process:
The first step: check whether the hydraulic oil level is normal, and add hydraulic oil if necessary.
Step 2: Check whether the safety lock fuse is intact. If it is intact, use a multimeter to check whether the solenoid valve terminal 9 # line is energized. If it is not energized, check whether the travel switch works normally. And repair; if the 9 # line of the solenoid valve end has electricity, remove the solenoid valve to conduct the power-off test. If the spool cannot be operated, the spool is stuck or the solenoid coil is damaged, repair or replace.
Step 3: Check whether the pilot pressure of the outlet of the safety lock solenoid valve is normal. If it is abnormal, the pilot pressure of the pilot pump needs to be checked. If the pressure is normal, it means that the pilot solenoid valve core is leaking seriously, and the repair or replacement; if the pilot pump outlet pressure is not Normal, the pilot valve overflow valve is faulty or the pilot gear pump is seriously worn, repaired or replaced; if the pilot pump outlet pressure is 0.
The excavator engine works normally, and the movement of the working device becomes slow
Main reasons:
(1) Insufficient hydraulic oil quantity, deterioration
(2) Poor pumping and oil return
(3) Low pilot pressure
(4) Pilot oil line is not smooth
(5) The relief pressure of the main valve is low
(6) Diagnosis process of serious pump wear: the first step: check whether the hydraulic oil is deteriorated and whether the grade is correct, and replace it if it does not meet the requirements. The second step: check whether the suction and return oil passages are smooth, and if they are not smooth, they should be cleaned or replaced. Measure the pressure of the two main pumps. If the result is zero, it means that the engine output power is not supplied to the hydraulic pump. Under this condition, check whether the coupling and the main pump shaft are broken. If the coupling or the main pump shaft breaks, replace it in time.
The third step: check whether the pilot oil pressure is normal, if it is too low, it should be adjusted to the normal value.
The fourth step: check whether the pilot oil circuit is smooth, if not, it should be cleaned or replaced.
The fifth step: check whether the relief pressure of the main valve is normal, if it is too low, it should be adjusted to the normal value.
The sixth step: check whether the hydraulic pump has reduced volumetric efficiency due to wear. If the pump is worn, the hydraulic pump should be replaced.
