When the wheel loader comes out with malfunction or abnormal condition, the machine should be shut down first. Then, the operator analyzes the malfunction in line with the fault features and makes a conclusion about the malfunction preliminarily. It is not appropriate for the machine to operate with fault. Otherwise, the fault would become more and more severe with the continuation of the operation.

The fault may be aroused by many factors such as production, operation, working environment, maintenance, etc. Some faults influence each other. For example, the insufficiency of the coolant for diesel engine can not only lead to abnormal temperature rise of the water and lubricating oil of the engine, but also influence the oil temperature rise of the bi-changeable system. So, we need to find out the real cause of fault to achieve thorough fault removal.

We should make the fault inspection and analyzing process step by step with the combination of theoretical knowledge and practical experience. In general, we often take the methods of observing, touching, listening, smelling and testing comprehensively to conduct the troubleshooting.
1. Observing
We should firstly observe the meters about the reading changes, the situations of each connecting part, the leakage of the sealing surface, the abnormal phenomena relating to the oil, fuel and water, exhaust smoke color of diesel engine, etc.

2. Touching
Through the touch feeling, we can check the surface temperature, connection situation and vibration situation of each part.

3. Listening
We can listen to the sound emitted by the working element to know the sound changes and determine the abnormal sound position.

4. Smelling
We can check whether there is the abnormal smell of the oil and each component in virtue of sense of smell.

5. Testing
The test can be conducted according to the requirements in the case of allowable conditions. As to the fault for which the reason cannot be found out immediately, the testing personnel can appropriately drive or operate the wheel loader to observe the fault and analyze the reason in the premise of ensuring safety.

Through the above methods, we can get a preliminary determination about the fault. After the preparation for the disassembling, the maintenance personnel should disassemble the machine in accordance with the order. During the disassembling process, he should observe the parts and components about the service conditions carefully and place the parts and components in sequence. For confirming the reason of fault further, the maintenance personnel should protect the original signs of the fault area and make a record. After making clear the reason of fault, he can start the repair work.

Quick and accurate fault reason identification needs comprehensive understanding of performance and operational principle of whole machine as well as continuous learning and experience accumulation. For keeping high quality service, it is necessary to establish the sound management system and the service team with service technicians having good technology, strong sense of responsibility and rich experience. Only in this way can the fault be solved in line with the correct operating method, assembling procedure and commissioning requirements.