Modern excavator repair
Cases of experience and lessons in fault diagnosis of modern excavators (16)
Symptom: After working for 76 hours, the main control valve is seriously leaking. User Comments: Request to be processed as soon as possible. 1. The agent judged that there was a crack at the bottom of the main control valve, causing serious oil leakage. 2. Considering that the user's new car and the tight construction period, the agent first uses its own inventory machine to replace the user. 3. The agent applied for a new main control valve, but we carefully checked the bottom of the main control valve that leaked oil and found that the so-called cracks were only the shell casting texture. After disassembly, it was found that oil leaked from a check valve located between the two halves of the main control valve. Normal after tightening. 4. The agent agreed to reserve the main control valve as a maintenance part. 1. Find the real reason for the failure that occurs. 2. Careful inspection can avoid unnecessary application errors and corresponding losses. Symptom: The instrument panel does not display after working for 6 hours. User Comments: Request to be processed as soon as possible. 1. The malfunction occurred after the agent replaced the pad in the cab. 2. Because there is no such failure in changing the pads of other models.
First considered unique to the R260LC-7. 3. Before replacing the leather pad, the machine is working normally, and it can be judged that what line is broken or the plug is loose during the replacement. 4. The wiring of the cab is normal. Open the bottom plate, and most of the wires are pulled out from the plug. After repairing, the machine works fine. Before a new car fails, there are usually factors that cause it. Therefore, we must seriously ask the users and agents, the principles, so that the time for failure analysis and judgment can be greatly reduced. Symptom: The second test run of the new car cannot start. User requirements: Not handled within 24 hours, 1. Before we rushed to the construction site overnight, the agent had checked for 2 days, and the obstacle could not be ruled out. 2. After arriving at the scene, the car was found to have a crusher installed. The personnel and the crusher installer learned that when the crusher was ready for test run, it was found that it could not hit the car. We suspected a breaker problem, but the breaker installers insisted that it was not a breaker problem.
3. After removing the control oil circuit of the crusher, test run and start normally! Found the real reason: the solenoid valve of the crusher is open and loaded, so it can't start! 1. When you encounter something, you must have confidence in the product. You are an excellent engineer! 2. For the use of additional pipelines of the machine, you must first understand the principle of the entire special device, from simple to complex, from surface to interior, and gradually check. And the user should emphasize the company's product warranty policy in this regard. Symptoms: The vehicle has poor working continuity, and the engine speed drops by more than 400 revolutions during compound action. User comments: This car is a new machine, and it has just worked for more than 100 hours, and it is required to replace the new machine. 1. The agent went to the inspection several times, and they all thought it was normal. Years of operation experience considered it abnormal. 2. On-site inspection, as reflected by the user: The rotation speed drops greatly and the working speed is slow. 3. Check the EPPR valve pressure. The H and S modes are always 0 bar. 4. Switch to U mode and set the EPPR valve pressure to 15 bar.
The continuity of the machine's action becomes better, but from the dashboard and actual measurement, the pressure does not change with the change of action. 5. Judging from the above 4 items, the connection between the CPU and the EPPR valve is normal, the EPPR valve works normally, and the problem lies with the CPU. 6. Test the car after replacing the CPU, and the whole car works normally. 1. The problems reflected by users should be taken seriously. Even if the users have doubts about the machine due to psychological factors, the machine can be adjusted or adjusted appropriately to eliminate the users' doubts. 2. The performance and technical parameters of the vehicle must be understood, and the application must be valued. 3. Mastering the self-diagnostic function on the dashboard and skilled acquisition of various parameters can speed up troubleshooting. Symptom: The air filter alarm switch is damaged for many times, causing false alarms. Customer opinion: There are problems with the quality of Hyundai's accessories. 1. The agent service personnel went to check and checked with a multimeter, and found that the alarm switch resistance value was normally on (normally on).