1. First, check whether the hydraulic pilot opening prompt appears on the display screen. If it appears, it means that the pilot travel switch is in good condition. If it does not appear, replace the pilot travel switch
2. Check whether the 606 line of the pilot solenoid valve is at 24V voltage after the hydraulic pilot is turned on. If yes, check the pilot solenoid valve. If not, check the relevant circuit and ec-7 control
3. If the pilot solenoid valve is good, check the main pressure and pilot pressure of the front and rear pumps (check with a pressure gauge)
4. If the pressure of the front and rear main pumps is 3Mpa and the pilot pressure is 0, the pilot pump or pilot overflow valve is damaged
5. If the pressure of the main pump and the pilot pump is, the connecting rubber plate or the main pump is damaged
6. If the main pump pressure rises to 0 and the pilot pressure is normal, the main overflow valve is damaged
7. The last inspection of this machine is that the connecting rubber plate is damaged. After replacing the connecting rubber plate, the machine works normally
The failure of the whole excavator is often caused by the following reasons:
① There was no installation error during installation, and the buffer rubber block between the engine and the hydraulic pump was damaged
② The main shaft of the hydraulic pump is broken, or there is something wrong with the servo system, especially the regulator in the hydraulic pump
③ The fork is installed incorrectly or the adjustment amount is too large during commissioning, resulting in fracture
④ The connecting block with the engine is installed reversely
Of course, the specific cause still needs to be investigated on the spot
After field troubleshooting, it was found that the buffer rubber block between the engine and hydraulic pump of the excavator was damaged, resulting in no action failure of the whole vehicle of Carter 330c excavator. After replacing the buffer rubber block between the engine and hydraulic pump, the excavator returned to normal operation
There is no action fault on the whole excavator. Check:
1) Check whether there is 24V voltage at the pilot cut-off switch
2) Check whether the pilot solenoid valve is intact and whether the voltage is normal
3) Check whether the pilot valve element is stuck
4) The outlet pressure of the pilot pump was measured with a pressure gauge and found to be only 0.5 ~ 0.7MPa. The spring in the pilot pump overflow valve was broken during disassembly and inspection
Doosan and Daewoo excavators have no action fault cause: the spring of the pilot pump overflow valve is broken, resulting in low pilot pressure
Troubleshooting: Troubleshooting after replacing the spring
