It is natural for a vehicle to enter the factory for maintenance, but some repair shops are really annoyed by their irresponsible attitude towards vehicle maintenance. A heavy truck HOWO dump truck came to a repair shop for maintenance because of the bearing bush fault. The bearing bush fault occurred one week after the maintenance leaves the factory. Why? Let’s have a look.
We can see from the main bearing bush that there are obvious marks of bearing bush powder particles embedded on the bearing bush, and the connecting rod journal of the holding Bush belongs to the highest level of holding Bush + rolling bush. The outer surface of the journal adheres to the residue of the bearing bush alloy pasted on the Journal after melting, and the crankshaft is basically scrapped. The vehicle will stop driving again within a week because of this undesirable fault, Overall, the loss situation is not optimistic.
Card users generally believe that they will not hold the tile as long as the oil pressure is enough. This is not all right. There is a special case. We first analyze the trend of engine oil. The lubrication route of the oil is that after the oil pump pumps the oil from the oil bottom, it enters the main oil passage through the oil radiator and filter to reach each friction surface for lubrication.
Therefore, we thought that the first time the car entered the factory for maintenance, it did not clean the main oil duct and replace the oil radiator. Due to the failure of the bearing bush, there will generally be alloy debris on the bearing surface, resulting in the blockage of the oil filter and the opening of the safety valve. The unfiltered oil directly enters the oil radiator and the main oil duct through the safety valve and is deposited.
During the first maintenance of bearing bush fault, the main oil passage was not cleaned and the oil radiator was not replaced. According to experience, only 6 connecting rods were replaced and then loaded for use. As a result, this part of debris blocked the filter again, opened the safety valve, and the unfiltered engine oil directly entered the main oil passage to the friction surface of Dharma, resulting in residue pressing and embedding of the main bearing bush, damage and reduction of the clearance of the connecting rod bush, resulting in high-temperature melting of the bearing bush alloy surface and bearing bush holding phenomenon.
Vehicle maintenance is a meticulous work. Many times, the experience of inertial thinking is very harmful. The secondary failure of the vehicle is caused by the negligence of the repair shop. Therefore, in the maintenance process, we should clarify our ideas, check and clean it item by item, so as to ensure that the repaired vehicle does not make mistakes and ensure the maintenance quality. In view of the current maintenance environment, the owner also needs to remind the maintenance personnel to pay attention to some key points to minimize the maintenance risk.
In the current vehicle maintenance environment, as a car owner or driver, you should learn some basic maintenance knowledge and supervise the whole process of maintenance. Although it seems to be a lot of trouble, it is more reliable to spend more time in order to reduce unnecessary trouble. The repair shop should also strengthen management and eliminate such secondary faults caused by its own negligence, so as to better maintain its reputation.
Analysis and summary of tile smashing fault of Nanjing Iveco Yuejin xiaofuxing
Violent disassembly and opening of iron shell to see the true face of inferior filter
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