Tractor Fault Diagnosis Method: Remember The Four Word Mnemonic And Easily Diagnose Tractor Faults

"Wangwen Wenqie" is an important diagnostic method in traditional Chinese medicine. Similarly, for tractor repair, borrowing the "Wangwen Wenqie" working method into the fault diagnosis of tractor hydraulic systems is also very effective and practical. Let's take a look at the "observation, hearing, questioning, and cutting" diagnostic method for diagnosing faults in tractor hydraulic systems.

The so-called "observation" refers to seeing and observing the symptoms of tractor malfunctions.
Look at the lifting and carefully observe the changes in the speed of the tractor's lifting and lowering of agricultural machinery, as well as whether it is smooth and stuck. If the lifting is too slow, it may be due to excessive load or low pressure; If the descent speed is too fast, it is unsafe and the descent speed control valve needs to be readjusted; If the agricultural machinery swings too much, there may be looseness or wear on the connecting rods. It is necessary to carefully inspect the loose and worn parts.
Looking at the color, prolonged heating can cause changes in the appearance of hydraulic system pipelines and gear pumps, mostly appearing yellow. Checking the pipeline, that is, diagnosing faults by observing the appearance of the pipeline, mainly observing whether there is oil leakage at the tractor oil pipe joint, whether the oil pipe fittings are deformed or damaged, and whether the control rod components are deformed or damaged.

The so-called "smelling" diagnosis refers to smelling the odor and listening to the sound.
After the tractor malfunctions, one is to smell for any abnormal odor, and the other is to listen for any abnormal sound. For example, when a tractor with agricultural machinery is lifted and there is a "creaking" sound, it is often caused by poor sealing of the distributor safety valve or valve stem, resulting in automatic settling;
If there is no obvious "creaking" sound, but the agricultural machinery has a slight automatic settlement phenomenon, which is mostly caused by poor sealing of the oil cylinder piston; If there is no obvious "creaking" sound, but there is a phenomenon of rapid automatic settlement of agricultural machinery, it is mostly caused by poor sealing of the distributor one-way valve;
I heard a loud noise coming from near the safety valve, mostly due to excessive pressure causing the safety valve to open and unload oil. The main reasons and treatment methods for this noise are: (1) After the high-pressure elevator is raised to the highest position, the handle does not return to the neutral position, and the safety valve opens to discharge oil, making noise. The handle should be quickly returned to the neutral position; (2) When the non high-pressure elevator is lifted to the highest position, the inner lifting arm collides with the shell, and the safety valve opens to discharge oil, making noise. The lifting height should be quickly reduced and readjusted to ensure a 3-5mm gap between the inner lifting arm and the shell when lifted to the highest position.

The so-called "inquiry" diagnosis is to inquire about the symptoms of a malfunction.
In the diagnosis of hydraulic system faults in tractors, consultation refers to the maintenance personnel asking the driver about the operation status of the tractor, understanding the maintenance and repair of the hydraulic system and the working conditions of the hydraulic components, inquiring about the process of the fault occurrence, and determining whether the fault is sudden or gradual. Because the operator is familiar with the performance of the tractor and is present on site when a malfunction occurs, the information provided is very helpful for analyzing the malfunction. Maintenance personnel usually inquire about the following situations:
When did the tractor hydraulic system undergo maintenance and repair.
2. Whether the hydraulic oil grade meets the regulations and whether the dosage is appropriate.
3. Did you accidentally press a button or execute a program when the malfunction occurred.
4. Compare the usage of the hydraulic system before and after the malfunction in order to analyze the cause of the malfunction.
5. What are the abnormal phenomena during the operation of the tractor hydraulic system, and whether there are signs of smoking, odor, failure to lift, weak lifting, falling, abnormal vibration, etc.
By asking, one can often obtain useful information, which is beneficial for analyzing the cause of faults based on the working principle of the equipment and making timely repairs.

The so-called "cutting" diagnosis refers to touching and measuring.
If the temperature of the hydraulic system is too high during normal use of the tractor, it will cause damage to the hydraulic system. Firstly, it will affect the oil suction capacity and volumetric efficiency of the hydraulic pump; Secondly, it can cause abnormal operation of the hydraulic system, unstable pressure and speed, and unreliable operation; Thirdly, the internal and external leakage of hydraulic components will increase; Fourthly, it will accelerate the oxidation and deterioration of the oil.
During work, attention should be paid to the temperature rise of hydraulic oil at all times. During normal operation, the oil temperature of hydraulic oil and chassis oil should not exceed 60 ℃. Otherwise, the tractor should be stopped, the problem should be identified, and timely maintenance should be carried out. Without measuring instruments, the temperature rise of the hydraulic system can be determined by touching it with your fingers.
The tactile sensation of human fingers is very sensitive and can accurately determine various abnormal temperature rises, with an error of 3-5 ℃. At around 40 ℃, the touch feels like touching a high fever patient; At around 60 ℃, it feels very hot to the touch, but can withstand it for about 10 seconds; When the temperature is above 80 ℃, instantaneous contact can cause a tingling sensation to the touch, and a slight delay can lead to burns. When conducting a surgical examination, pay attention to safety! Prevent finger burns! When checking the temperature rise, attention should be paid to the touch method of the hand. Generally, use the back of the index and middle fingers of the right hand to quickly and lightly touch the surface of the machine. After determining that the temperature is not high and will not cause damage to the skin, you can use your fingertips or palms to touch it.

I hope this article can be helpful to you!