First observe whether there are cracks and welding marks on the big arm and the small arm of the excavator. If there are cracks, it proves that the working condition of the machine was bad before and the machine was seriously damaged.
Second, observe whether the cylinders bump. If there is a bump, it proves that the machine has been seriously damaged, and the oil cylinder will always leak oil, even if a new oil seal is replaced, it will continue to leak oil in a short time. Therefore, it is very important to check the oil cylinder when buying second-hand machines.
Third, check the four-wheel area, first observe the driving wheel, guide wheel,
Fourth, the engine is commonly known as the "heart" of the excavator, so when buying a second-hand machine, you must carefully check the engine and listen to whether the engine is noisy, whether the power is strong, and whether the speed drops when working. At the same time, you can also enter the system to observe whether the exhaust volume is large. If the exhaust volume is large, it proves that the engine works for a long time and needs to be overhauled. In addition, observe whether there is blue smoke when starting the engine, which will appear before starting work.
Fifth, check the rotating motor to see if it rotates strongly and makes a lot of noise when it rotates. If there is noise, we need to observe where the noise comes from, and then carefully observe whether there is a gap in the rotating chassis. Secondly, carefully observe the distributor of the excavator. Because the function of the distributor is mainly to control the movements of various tasks, it is necessary to see whether the various working movements of the excavator are coherent and whether there is a pause when buying a second mobile phone for trial operation. Whether the excavation is powerful or not, the test method is to dig up a bucket of soil, and then lift it to the highest point to observe whether there is internal leakage in each cylinder. These precautions are very important when buying used cars, so you must choose cars carefully.
Six, the hydraulic pump is the power element of the hydraulic system, its role is to convert the mechanical energy of the prime mover into the pressure energy of the liquid, and the oil pump in the hydraulic system provides power for the whole hydraulic system. Therefore, the inspection of hydraulic pump is also very important. When buying a second mobile phone, you should touch the hydraulic pump with your hands to see if there is any feeling of shaking your hands, then check whether the hydraulic pump has cracks and serious oil leakage, and try it out to see if the hydraulic pump has power and noise.
Seventh, check the electrical system to see if all circuits can work normally, and then enter the computer system to check the motherboard. If you can see the working conditions after entering the system, such as revolutions, pressure, maintenance mode, etc. , which proves that the computer board is normal.