Precautions for buying a second-hand excavator

　　1.Check the bucket and boom

　　Excavators are not always used as an excavating machine,and builders sometimes use them to drive piles or use them to lay pipelines.Therefore,users need to pay attention to the condition of the bucket to ensure that there are no problems with the piling,crushing and walking devices.Another important part is the connecting pin and bushing of the bucket cylinder.The tightness of these places must be checked.Many problems are caused by negligence in maintenance and inspection.Another key point is to carefully check the connection between the rear arm and the excavator.If the connection under the rear arm is worn excessively,the value of the entire equipment may be lost.

　　2,check the hydraulic cylinder and tubing

　　Oil leakage means that the entire oil circuit may be contaminated.It is very important to check hydraulic cylinders and oil pipes.A good situation is that the chrome-plated surface of the hydraulic cylinder has no scratches,dents or traces of oil leakage.If there is hydraulic oil leaking out,the dust may have contaminated the hydraulic system.Also make sure that the cylinder wall is not damaged or has dents.The gap between the cylinder and the cylinder wall is very small.As long as there is a debris in the pipeline,a large amount of metal chips will be generated due to wear and tear of the cylinder during operation,which will remain in the hydraulic system.

　　3,pay attention to the welding of the body

　　Check carefully for cracks on the excavator and welding marks left by non-original manufacturing.These things indicate that the machine has been overused.Another good way is to use a straight board on the position of the rear arm and stick to see if there is any misalignment or distortion.Pay special attention to the repair of excess steel plates.There may be some scratches and dents on the second-hand excavator,but if there are too many patches on the machine,it may mean that the equipment has been used for a long time.

　　Second-hand excavator purchase precautions two

　　1.Check the rubber track and chassis

　　The rubber track on the small excavator is different from the steel track on the large machine.It is suitable for grass and driveways.In many cases,users will not check the wear of the rubber track at close range like the steel track.As a result,only the wear of the rubber track was seen,but not a large amount of wear on the sprocket and supporting wheels.You can estimate its usage by checking the cracks and edge wear on the rubber track,just like paying attention to the tire when looking at the tire wear.The lines are the same.

　　Due to the difference in usage and soil conditions,the working life of rubber tracks is also very different.Generally speaking,its average life span is about 2000 hours.But if you work in a rocky or easily abraded environment,the service life will be halved at this time.On the contrary,in a better environment,the operating life will be correspondingly doubled.

　　When users check the track and chassis,don’t forget to drive to check the oil level and cleanliness.This part is easily overlooked,and there is usually very little oil left.If the amount of oil is already low,and water or other things enter,it will cause greater trouble.

　　2,start-up operation inspection

　　After the engine is warmed up,tilt the machine to make it stand on only one crawler,and then alternate the crawlers on both sides to stand.Pay attention to how many such actions can be completed in 30 seconds or 60 seconds,and then compare with other crawlers.The crawler walking device of the excavator is a built-in flow meter.If the two do not have the same flow,then there is a problem.

　　Another way to detect is to drive the excavator on flat ground for 10 meters.If it is running in a straight line,you can know that the walking devices on both sides are running equally well.Also check the slewing ring gear and slewing bearing.Under normal circumstances,the upper part can start to rotate smoothly and stop accurately,with little or no deviation.For small excavators,the slewing ring gear and slewing bearing should have the same long life as the machine,so any questions about this part must be paid attention to.

　　3,check the engine cover

　　Driving operation inspection,the engine cover should be opened and the exhaust pipe should be checked for signs of smoke.You can pull out the dipstick and check for smoke.Too much smoke usually indicates that the piston ring needs to be replaced,and the engine may be overhauled soon.

　　Check the air filter device and all pipes and pipe clamps.A little dust is enough to destroy the entire engine.Pay attention to the dust or dirt accumulated in the terminal,also check the fan to ensure that the belt is tight,check the radiator to ensure that it is clean,ignoring the cooling system and air intake system may cause the engine to overheat,thereby shortening the life of the machine.

　　The basic inspection also includes checking the radiator fluid and engine oil,checking the degree of corrosion of the battery,and checking whether there is any obvious leakage around the engine.Minicomputers are used more in special environments,such as wire burying projects,pipe laying,trenching operations,etc.,and their annual use time is relatively short.However,the small excavators rented by the leasing company have a long time of use each year,so the life of the machine will be relatively short.

　　Second-hand excavator purchase precautions three

　　1,don’t look at the time to see the car status

　　Most buyers pay more attention to the readings of the timetable when buying a second mobile phone.They think that excavators with short hours are in good condition.This habit is often changed from the habit of looking at mileage in the automobile industry,but excavators The number of hours in the middle hour meter is not necessarily the actual number of hours.If you buy a machine based on the number of hours alone,you may often spend a lot of money to buy a classic car.Therefore,buying a second-hand excavator cannot just look at time.Although time is indeed a consideration for buying a second-hand excavator,it is definitely not an important factor.

　　2,pay attention to the real wear and tear

　　The chain plates,the supporting wheels,and the ribs on the inside of the forearm near the bucket,the above three items can accurately tell you the vicissitudes of the excavator's experience,they can tell you that the excavator used to work on a hard mine bed.Still working in the soft deep forest,or walking on the avenue of urban construction.

　　Generally speaking,the three major excavators working in the mine have a much higher degree of wear in the same hours than the excavators for earthmoving operations.Take two vehicles that work for more than 5,000 hours as an example.The difference is in the chain plate of the mine.The chain spurs are not worn uniformly,and there will be sudden scars.There will be traces of violent bumps on the metal surface by rocks during the excavation process,especially on the stiffeners on the inner side of the forearm,and the excavator chain plate for earthwork construction The wear of the ribs on the inner side of the support wheels and the forearm is more delicate and smooth,and it is difficult to see the traces of collision with rocks in a large area.Such excavators often have a longer service life than excavators that do heavy work in mines.The purchase of excavators for earthmoving will naturally reduce a lot of maintenance and repair costs,thereby increasing revenue.

　　3,pay attention to the various indicators of the engine

　　First,check the appearance to see if there is a large area of​​water leakage,oil leakage,antifreeze missing,oil missing,and the oil filter element is the original filter element.Because during the maintenance period,if the owner can meticulously and timely maintain the excavator and use the manufacturer's genuine accessories,this will greatly reduce the wear of the excavator's parts and extend the service life of the excavator.

　　After checking the oil and antifreeze,we start to check.After the engine is started,first observe whether the engine is running smoothly at idle speed and whether the lower exhaust gas is too large.Next,look at the smoke color of the engine.If blue smoke is coming out,it is the kind of smoke that you feel when you stand in front of the exhaust pipe and your eyes are very hot.This means that the cylinder piston ring and barrel of the excavator are worn out.Caused by oil burning failure.If white smoke is emitted,it may be water vapor,which may be the cylinder head gasket damage.If it emits black smoke,it is likely that the injector is damaged.