At present, the use of agricultural machinery in rural areas is relatively common, and various faults occur from time to time during operation. In normal maintenance, although meters and instruments can be used to identify the technical status of agricultural machinery parts, agricultural machinery operators can preliminarily judge the failure of agricultural machinery based on the "three senses" of vision, hearing and touch.

1. Visual identification. It can identify the wear of surface parts and the quality of surface materials of parts. Such as cracks on the cylinder block and cylinder head, fatigue and falling off of the gear and flow bearing surfaces, annealing blue or pitting after serious burning of the fuel injector and exhaust valve, wear and burning of the friction materials of the clutch and brake, meshing marks of the gear pair, light leakage between the piston and the cylinder sleeve, etc.

2. Auditory identification. Hearing identification can use a small hammer to gently tap the inspection part of the metal parts to judge whether there are cracks inside and whether the connection is tight from the sound. Generally, the sound of tight and intact parts is clear and crisp, and the sound of defective parts is muddy and dumb. This method can be used to identify whether the crankshaft and side bar have cracks, the combination of bearing alloy and body, and whether the rivet connection is firm. In addition, the meshing condition can also be roughly judged from the sound emitted by the running gear set.

3. Tactile identification. Tactile identification can be shaking by hand, and the gap size can be judged by feeling, without measuring with measuring tools. Such as the clearance between valve stem and valve guide, radial and axial clearance of flow bearing, etc.