How to do well the maintenance of large and medium tractors

As one of the main machines and tools of agricultural mechanization, large and medium tractors are the main embodiment of modern agriculture and one of the main means to promote farmers' income and agricultural efficiency. But also often because the manipulator can not carry out the correct maintenance, resulting in machine life and performance are seriously affected. To solve this problem, we should start from the following aspects.

Daily maintenance should be done before starting the tractor
1. Carefully clean up the oil and dust on the surface of the tractor.
2. Check whether the connecting bolts and nuts of main parts are loose and tighten them in time.
3. Check whether the diesel, engine oil and cooling water are sufficient.
4. Check the oil level of engine oil pan, and add enough oil if it is insufficient.
5. Check the tire pressure.
6. After the engine starts, let the locomotive run at idle speed for 3-5 minutes, let the lubricating oil fully enter the working parts, and check whether the instrument, light and horn are normal.
7. Check whether the brake oil pipe is worn or not and whether the pipe connection is tight. Pay special attention to whether the brake oil pipe collides with the bridge package and the frame.
8. Check the tools on the vehicle.
9. Fill in the work diary.
Maintain the main parts regularly
1. Maintenance of air filter
Frequently check whether the sealing of each pipe connection of the air filter is good. If the nuts, bolts and clamping rings are loose, they should be tightened in time. If the parts are damaged, they should be repaired or replaced in time.
It is generally required to maintain the air filter every 100 hours. When maintaining the paper filter element of dry filter, clean it with a soft brush, and then use 0.4-0.6mpa compressed air to blow the filter screen, oil storage pan, central pipe and other parts from the filter element. Dry the filter screen and spray a little engine oil before assembly. The oil pan should be replaced with filtered oil. When adding the engine oil, it should be filled according to the oil level mark. The oil level should not be too high or too low. The sealing rubber ring should be well sealed during installation.
2. Valve maintenance
After 800 hours of operation, check and adjust the valve clearance and remove the carbon deposit; after 1200 hours of operation, check the sealing condition of the valve and seat, and grind or replace new parts if necessary.
3. Maintenance of diesel filter
The impurities in the filter will continue to increase with the extension of service time, and the filtration capacity will decline; the aging and damage of other parts, such as gasket, will cause "short circuit", that is, diesel directly enters the oil pump without filtration. Therefore, it is necessary to carry out maintenance and pay attention to the following points:
(1) The section and center of the filter element should be well sealed. (2) When maintaining the paper filter element, soak it in diesel for a period of time, and then brush it with a soft brush. Air can also be used to pump air into the filter element to blow dirt from the inside to the outside.
(3) After the filter is disassembled, the air should be exhausted.
4. Maintenance of fuel injector
Generally, the injection pressure and quality of the injector should be checked and adjusted after the tractor runs for 800 hours.
5. Maintenance of lubrication system
(1) Add lubricating oil in time, and check the oil level of oil pan before starting or continuously working for more than 10 hours.
(2) Clean the lubricating oil filter regularly and replace the filter element.
(3) The lubricating oil in the oil pan should be replaced regularly, which can be appropriately advanced or delayed according to the actual situation and oil quality.
(4) Clean the oil circuit. The oil circuit should be cleaned when the diesel engine works for 500 hours.

(5) Adjust the pressure of lubricating oil circuit. When the diesel engine is working, if the lubricating oil pressure is lower than the normal pressure, the reason should be found out. If the oil pressure decreases due to the softening, eccentric wear or breaking of the pressure regulating spring, the spring preload should be adjusted or the spring should be replaced to restore the normal pressure.

6. Maintenance of clutch
(1) Always check the free stroke of the pedal and the separation clearance of the three release levers.
(2) If the release lever or release fork is seriously worn, replace it with a new one.
(3) Check the lubrication of the bearing regularly and inject grease if necessary. When the tractor works for 500 hours, the release bearing should be removed for cleaning. After cleaning, put it into a container with butter and heat it to make butter permeate. Take it out and put it on after it solidifies. Note that the temperature should not be too high when heating.
7. Maintenance of hydraulic system
(1) Regularly check the height of the hydraulic oil surface. If it is insufficient, add or replace the hydraulic oil to keep it clean.
(2) When cleaning the internal parts of the hydraulic system, in order to prevent the oil passage from blocking or causing leakage at the sealing place, it is forbidden to wipe with cotton.
(3) Do not use gasoline to wash the rubber sealing ring to avoid aging and deterioration. When assembling the sealing ring, apply a little oil or soapy water to prevent shearing and tearing.
(4) Oil pump, distributor and oil cylinder are precision parts, which are generally not removed at will.
8. Electrical system maintenance
Check the connection of all wires, which must be tight and reliable, and shall not be stained by diesel oil and engine oil, and prevent contact with the hot part of diesel engine, and check whether the insulation performance of wires is good.
9. Battery maintenance
(1) Maintenance free battery usually does not need special maintenance. Observe the observation hole of the hydrometer: green means that the power is sufficient; gray means that the power is insufficient; black means that there is basically no power.
(2) When the battery observation hole is gray, it needs to be recharged; when it is black, it should be replaced.
(3) The storage battery should be stored in a clean, dry and ventilated place with the temperature between 0-40 ℃. It should be handled with care to prevent collision and not upside down.
(4) The battery terminal and power line connector shall be firmly connected to prevent the terminal from melting during starting. In order to prevent oxidation and corrosion of terminals, Vaseline should be applied on the terminals.
(5) Keep the external terminals of the battery clean. (6) Regularly check whether the generator output voltage meets the standard, and the voltage is (14.2 + 0.2) v.
(7) When charging, ensure that the indoor air is unblocked, away from open fire, electrolyte should not be splashed on the body or clothes, so as to avoid accidental injury.
(8) When the electrolyte of ordinary battery is insufficient, it should be filled in time.
(9) During the charging process, the temperature of electrolyte should not be higher than 45 degrees, and the charging current should be halved or the charging should be stopped to achieve the purpose of cooling, but the charging time should be extended accordingly.
(10) At the end of charging, the power supply should be disconnected before the power supply is disconnected from the pole, so as to prevent fire or explosion caused by rubbing fire.
10. Maintenance of engine cooling system
(1) The engine coolant can be boiled tap water or antifreeze. Before starting, check whether the cooling water in the radiator is full and whether there is leakage.
(2) Regularly remove the scale in the cooling system to ensure the heat dissipation of the heat exchange surface.
(3) Always check the radiator core parts for weeds, dust, oil and other blockage.
(4) Check the thermostat performance on time, otherwise it will affect the cooling water circulation and reduce the cooling effect.
Precautions for good maintenance
In the daily use of large and medium-sized tractors, the maintenance methods of different types of tractors are different, and they should be maintained according to the correct instructions. According to the inspection requirements of large and medium tractors, the following points should be paid attention to during the maintenance of large and medium Tractors:
1. Engine part: one is that the engine power and condition are normal. As the tractor has been parked for a long time, the three filters (air, oil and diesel) of the engine should be checked, cleaned and replaced. Another situation is that the power of the engine decreases, so the engine should be maintained.
2. Transmission part: if the clutch is not smoothly combined, slipping, incomplete separation, difficult to shift, rattling, etc., it is necessary to maintain the clutch, replace the friction plate in time, and adjust the clearance between the main and auxiliary friction plates, as well as the free travel of the clutch pedal.
3. Walking part: the tire should be in good condition, the air pressure should be appropriate, the left and right sides should be consistent, the steel ring should be free of crack and deformation, the screw should be tight, the toe in of the front wheel should meet the requirements, and the head should not swing; when the tire is inflated, it must be in accordance with the regulations, not too high or too low, so as not to damage the tire.
4. Steering part: the free stroke of the steering wheel shall meet the requirements, the operation shall be flexible and light, the steering tie rod and vertical tie rod shall not be deformed, the connecting device shall be reliable and not loose, and the pin shaft clearance shall not be too large.
5. Braking part: it should be checked frequently, and it should be removed for maintenance if the braking effect is poor. Adjust the free stroke of the brake pedal to meet the requirements, return quickly, and have interlocking and self-locking devices. At the same time, the braking effect of the left and right wheels should be consistent, and the braking is effective.
6. Lighting part: frequently check and maintain the frequently used turn signal, headlight and horn.