1. look at the appearance.

　　First of all, when looking at an old equipment, through different light and angles, we can see the color of some paint, and the wear of the walking part of the equipment. The appearance of this piece of gun tube has not been installed, the pipeline is original, or it is installed after itself, as well as the wear of the counterweight, including the side door, counterweight, whether it has been painted. We can judge it through different light angles. The appearance problem can be said to be a small matter or a big one. When someone asks for equipment construction, it depends on the old and new level of your equipment. At the same price, people will never abandon the old and the new.

　　2. look at the nameplate.

　　When buying a second mobile phone, most people are used to looking at the nameplate. The nameplate of the equipment is the same as the ID card of our citizens. It has the model and factory code of the relevant equipment. In the picture, Japan represents the production place of the equipment, and the code of the equipment can find its production date.

　　3. look at the steel seal.

　　It can be seen on some important structural parts. This is the vehicle identification number (frame number). It can be seen on the boom root, frame, oil tank and other parts of the excavator. Generally, it is steel stamp. According to this, you can inquire the date of the equipment leaving the factory through the equipment dealer or manufacturer. Steel seal is a problem ignored by many people. It is as important as the nameplate of the equipment. It is not easy to change the steel seal unless it is knocked out by the grinder.

　　4. Hour meter: according to the year of the equipment and the hour of the display, the average service hours of an excavator every year is about 2000 hours.

　　In addition, the regional differences have a great impact on the service hours of excavators. Because the frozen soil does not start in winter, the number of hours in Northeast China is less than that in South China. If you encounter a machine going up and down from the mine, you should be careful. According to the data of car collection, the machine is very young, and the mechanism parts look very attractive. But the machine for mining usually operates 24 hours a day, so such a machine has sold coolie.

　　5. look at the fuselage.

　　(1) look at the counterweight: it is commonly known as "ass" by the robot operators. The balance weight reflects whether a driver cherishes the equipment and the construction environment of the equipment. If the normal construction equipment is more than 3 years old, the paint below will be worn off, which is a normal phenomenon. If the counterweight of the machine is scratched, or the iron sheet outside is broken, this kind of equipment is basically the equipment that has been in the mine, or engaged in Demolition for a long time, or broken, normal excavation and simple earthwork engineering will not have this situation

　　(2) both sides of the fuselage: pay attention to whether the sheet metal has been made, if so, it indicates that there is a strong collision.

　　(3) cab: pay attention to whether there is any collision trace between the upper part of the cab and the door. If the equipment had been overturned or hit by stone during construction, it would not be so correct.

　　(4) engine cover: look at the construction environment of the equipment in summer, then pay attention to the red box of the figure. If the water level of the equipment has been very high and the engine cover has been opened for construction for a long time, the water temperature must be high! If the engine often has problems, the cover opens frequently, takes a long time, and is more likely to be damaged.

　　6. Excavator interior decoration and display: the seller will say that the display is broken at some time. In this case, it's better not to believe it. Many of them don't have computer boards. When you buy the computer board and want to repair it, it will become a big enemy! It's tens of thousands to buy a second-hand computer board. It's not necessarily as good as the original factory.

　　7. The engine is the heart of the excavator. Check whether the engine has been disassembled, and carefully check whether the installation position of the engine screws and surrounding parts is the same as that of the original factory. Also check whether the nameplate information of the engine and radiator has been changed, whether the valve cover has been removed, whether the diesel pump leaks oil, whether the harness is neat, whether the belt and fan are damaged, whether the water tank cover is rusted, and whether the cotton strip on the engine cover is damaged;

　　When the engine is running, you need to see whether its exhaust is large or not. If it is large, the engine needs to be disassembled for repair. Check whether the engine oil is burned or not, and check the gas taste and color of the exhaust port on the engine.

　　8. look at the water tank.

　　If there is a layer of yellow material around the water tank mouth, then the excavator often has a high water temperature problem!

　　9. radiator

　　Whether it's the radiator of the hydraulic system or the water tank, if it's the original one, if it's a new one, it should be noted that some of them are not only of high water temperature, but also of high hydraulic temperature.

　　10. Hydraulic pipeline:

　　Hydraulic pipes, distribution valves, rotating parts, regardless of the age of the machine, it depends on how many pipes are the original factory. If it is a replaced tube, you should carefully look at the position of its connection, so as to determine what fault it will have. This is ignored by many friends. It can be seen directly from the maintenance of an equipment.

　　(1) check the hydraulic pump: judge whether it is the original pump or the replacement pump, whether it has been repaired, and observe from the paint, oil pipe joint, flow regulator, etc.

　　(2) check the hydraulic condition: two people cooperate, one is for test run, the other is to feel the vibration of each oil pipe by hand. (low throttle, medium throttle and high throttle in sequence)

　　(3) check the distributor, rotary motor, rotary reducer, etc.; observe whether the oil pipes and screws are original ones; observe the oil scale and feel the viscosity by hand.

　　11. pumps

　　"Don't think that a new total achievement is worth buying. The original thing is the best. If the whole big pump of the equipment is knocked out, its position is not only here, but also related to the distribution valve. If it is knocked out suddenly, the scrap iron in it will flow in the hydraulic oil. If it is not handled well, the whole hydraulic system will be scrapped! "

　　12. Walking device

　　The walking part can also see the construction environment of the equipment. Take a close look at the motor corners in the blue circle, and the standard earth moving equipment is worn. If it is in the mine or in the environment of crushing and construction waste construction, the angle will be rounded.

　　13. track plate

　　Its angle determines the degree of wear. The wear and tear of earth equipment are all at right angles, and the equipment of stonework construction environment is basically ground flat. Some equipment has few hours, but the track shoes are severely worn. It is possible that there are many stonework constructions and the equipment has a long walking time. Long time travel wear motor easy to have problems!