Six Common Problems in Mini Excavator Repair:
1. Blindly Disassembling and Replacing Parts
Some repair personnel, lacking understanding of the structure and principles of construction machinery, blindly disassemble the machine based on a “roughly” or “close enough” approach. This not only fails to resolve the original fault but also creates new problems due to poor repair skills and workmanship. After disassembly, they often replace parts arbitrarily, increasing the customer’s expenses. Therefore, the cause and location of the fault should be carefully analyzed based on the symptoms before starting repairs. Avoid “blindly disassembling without understanding the cause.”
2. New Problems Arising After Replacing New Parts Without Quality Inspection Before replacing parts, a technical inspection should be performed. On the one hand, the quality of spare parts sold on the market varies greatly, with some counterfeit and substandard parts being sold. On the other hand, some parts may have changed in performance due to prolonged storage. Without testing, assembly often leads to malfunctions.
Therefore, maintenance personnel must conduct necessary inspections and tests before replacing new parts, including appearance and performance tests, to ensure that the new parts are fault-free and prevent unnecessary problems. Thirdly, neglecting part models and using incorrect or substituted parts is still common when repairing construction machinery. While some parts may be acceptable for emergency use, long-term use is harmful and affects the safety and technical performance of the machinery. Some maintenance personnel have limited understanding of the mechanical structure and principles, and many parts are of incompatible models, but they believe that as long as they can be installed, it’s fine, without considering whether they can utilize the machine’s technical performance.
Therefore, when repairing construction machinery, original model parts should be used as much as possible. Substitutes of other models should not be used, and incorrect parts should never be used. 4. Replacing Parts or Components in Pairs or Sets, or Installing Parts Backwards: Many components in construction machinery are paired, such as the plunger pair, delivery valve pair, and injector needle valve pair in a diesel engine fuel system; and the valve core and valve sleeve in a fully hydraulic steering system. These paired components undergo special processing and pair grinding during factory manufacturing, resulting in a very precise fit. They must always be used in pairs throughout their service life and should never be interchanged. Some mating components, such as pistons and cylinder liners, bearings and journals, valves and valve seats, and connecting rod big end caps and rod bodies, have relatively good fits after a period of break-in. During maintenance, care should be taken to assemble them in pairs to avoid mixing them up.
When repairing construction machinery, some parts have strict directional requirements for assembly. Only correct installation can ensure the normal operation of the parts. Some parts have indistinct external characteristics and can be installed in either direction, but in practice, reverse installation is common, leading to premature damage to parts, malfunction of the machinery, and accidents. Therefore, maintenance personnel must understand the structure and installation direction requirements of parts when assembling them and should not install them blindly based on assumptions. Fifth: Irregular Repair Methods, Treating Symptoms but Not the Root Cause. When repairing construction machinery, some repair personnel fail to adopt correct repair methods, believing that emergency measures are a panacea. They substitute “emergency” for “repair,” resulting in a phenomenon that “treats the symptoms but not the root cause.” For example, the common practice of “welding instead of repair” is a prime example. Some parts could be repaired, but some repair personnel, for the sake of convenience, often use the method of “welding them shut.” When the connecting threads of the hydraulic cylinder clevis and piston rod are damaged, direct welding is used, leading to irreplaceable damage to the cylinder oil seal and severe oil leakage. To make the diesel engine “powerful,” the fuel injection pump’s fuel supply and the injector’s injection pressure are artificially increased.
These irregular repair methods can only provide temporary relief and cannot be used long-term. It is essential to find the root cause of the malfunction and use proper repair methods to eliminate the problem. Repair personnel should pay attention to this. Six: Neglecting the Quality of “Small Parts” Leads to Increased Malfunctions
During maintenance work, some repair personnel often only focus on maintaining components such as fuel injection pumps, fuel transfer pumps, pistons, cylinder liners, piston rings, hydraulic pumps, control valves, brakes, and steering systems, neglecting the maintenance of “small parts” such as filters, relief valves, and various instruments. They believe that these “small parts” do not affect the operation of the machinery, and even if they are damaged, it is insignificant; as long as the machinery can function, they will continue to use it. However, it is precisely this lack of maintenance of these “small parts” that leads to premature wear and tear, shortening the service life of the machinery.
These “small parts” in all equipment are essential for the normal operation and maintenance of construction machinery, and are crucial for extending the service life of the machinery. Neglecting maintenance during repair work often leads to “small losses resulting in big ones,” causing malfunctions in the construction machinery. For micro-excavator issues, please leave a message or send a private message for consultation!
