Summary of difficult and miscellaneous problems of second-hand excavators from various brands

　Many users encounter many difficult and complicated problems during the use of second-hand excavators, and are unsure how to deal with them. They also do not know what precautions to pay attention to when using them. Shanghai Huacheng has compiled a complete list of difficult and complicated solutions for second-hand excavators for everyone.

Summary and classification of difficult and complicated diseases:

1. Second hand excavator moves slowly

2. Second hand excavator with slow overall movement

3. Second hand excavators cannot start a fire in the morning

4. Excavator's hot engine causes slow movement due to high temperature

　　The root cause of the slow operation of second-hand excavators:

　　1. Slow single action of an excavator refers to the appearance of slow speed during single operations such as walking, reversing, lifting large and small arms, and retracting the bucket. Common reasons include:

① The overflow pressure of the excavator's related components is too low

② Pump pressure sensor malfunction

③ Electromagnetic valve malfunction

　　2. Second hand excavator with slow whole vehicle/whole vehicle movement refers to the slow and powerless speed of the excavator no matter what movement it makes. Common problems include:

① The engine speed should not be too low or the engine power should not be lacking

② The output flow rate of the excavator hydraulic pump is relatively small

③ The excavator CPU, high and low pressure sensors, solenoid valves, and wiring are abnormal

④ The hydraulic components of the excavator are abnormal, the oil circuit is abnormal, or the flow rate is lost

⑤ The pressure value of the excavator pump is too low, lower than the normal value, resulting in a slow overall movement of the excavator

⑥ The wear of excavator pump components usually occurs on second-hand or long used excavators. The inspection method is to drain the oil and check if there are iron filings or other impurities in the oil. If there are iron filings, it indicates that the pump components are worn

⑦ Lack of pilot pressure or malfunction of PC-EPC solenoid valve

⑧ There are too many circuit problems (This question is commonly associated with Kobelco excavators, as there are many circuit issues with Kobelco excavators.)

　　3. The slow heating action of second-hand excavators in the morning is usually caused by the pressure and flow rate of the excavator pump valve group being lower than the standard value. Therefore, after this problem occurs, it is necessary to measure the pressure value of the pump valve group with a pressure gauge. If the pressure value is lower than the standard, it needs to be debugged, and measuring the flow rate requires professional maintenance equipment

4. The common reasons for slow operation of excavator thermal engine include:

① The hydraulic oil is too dirty and needs to be changed. When changing the oil, check the inlet filter screen for copper shavings. If there are copper shavings, it indicates that the excavator main pump is worn and needs to be disassembled for inspection

② The pilot filter element, return oil filter element, and suction filter element are blocked

③ The oil and filter element cannot be replaced immediately

④ There is oil sludge on the servo piston of the main pump regulator, and the inclined plate cannot be adjusted. The main pump always operates at a small displacement and lacks flow

　　5. What should I do if the second-hand excavator is easily embroidered?

How to effectively prevent rust on excavators after prolonged use? Here is an introduction to the rust prevention treatment of second-hand excavators:

① Before storing a second-hand excavator, it is necessary to determine whether to repair it by repainting or by repainting the entire machine based on the size of the area of rust proof paint peeling off on the outer surface.

② The anti rust method for the exposed metal parts of the working devices of second-hand excavator construction machinery, such as the ironing board of the second-hand excavator paver, the bucket of the second-hand excavator loader, and the scraper of the second-hand excavator grader, is to apply butter.