How to do a good job in the maintenance of large and medium-sized tractors

As one of the main machines and tools of agricultural mechanization, large and medium-sized tractors are the main embodiment of modern agriculture and one of the main means to increase farmers' income and agricultural efficiency. However, the service life and performance of machines and tools are seriously affected because the manipulator can not carry out correct maintenance. In order to solve this problem, we should start from the following aspects.
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Do routine maintenance before starting the tractor
1. Carefully clean the oil and dust on the surface of the tractor.
2. Check whether the connecting bolts and nuts at the main parts are loose and tighten them in time.
3. Check whether diesel oil, engine oil and cooling water are fully added.
4. Check the oil level of the engine oil pan and add enough if it is insufficient.
5. Check the tire pressure.
6. After the engine is started, let the locomotive run at idle speed for 3-5 minutes, let the lubricating oil fully enter all working parts, and check whether the instrument, light and horn are normal.
7. Check the brake oil pipe for wear and the fastening of pipe orifice connection, and pay special attention to whether the brake oil pipe is worn and collided with the bridge package, frame, etc.
8. Check the onboard tools.

9. Fill in the work diary.

Regularly maintain the main parts
1. Maintenance of air filter
Regularly check whether the sealing at the connection of each pipeline of the air filter is good. If the nuts, bolts and clamping rings are loose, they shall be fastened in time. If the parts are damaged, they shall be repaired or replaced in time.
Generally, the air filter shall be maintained every 100 hours. During the maintenance of 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 inside to the outside of the filter element. The filter screen shall be dried and sprayed with a little engine oil before assembly. The oil pan shall be replaced with filtered oil. When adding engine oil, fill it according to the oil level mark, do not make the oil level too high or too low, and ensure that the sealing rubber ring is well sealed during installation.
2. Valve maintenance
After the tractor runs for 800 hours, check and adjust the valve clearance and remove the carbon deposit; After 1200 hours of operation, check the sealing of valve and seat, grind or replace new parts if necessary.
3. Maintenance of diesel filter
The impurities in the filter will increase with the extension of service time, and the filtering capacity will decrease; Aging and damage of other parts such as gaskets will cause "short circuit", that is, diesel oil will directly enter the oil pump without filtering. Therefore, carry out maintenance and pay attention to the following points:
(1) The section and center of the filter element shall be well sealed.
(2) When maintaining the paper filter element, soak it in diesel oil for a period of time and then brush it with a soft brush. You can also pump air into the filter element with an air cylinder to blow dirt from inside to outside.
(3) After the filter is disassembled, the air in it shall be drained.
4. Maintenance of fuel injector
Generally, after the tractor runs for 800 hours, the injection pressure and injection quality of the fuel injector should be checked and adjusted.
5. Maintenance of lubrication system
(1) Add lubricating oil in time. Before starting the diesel engine or working continuously for more than 10 hours, check the oil level of the oil pan.
(2) Clean the lubricating oil filter regularly and replace the filter element.
(3) The lubricating oil of the oil pan shall be replaced regularly, which can be appropriately advanced or delayed in combination with the actual situation and the quality of the oil.
(4) Clean the oil circuit. Clean the oil circuit when the diesel engine works for 500 hours.
(5) Pressure adjustment of lubricating oil circuit. When the diesel engine is working, if it is found that the lubricating oil circuit pressure is lower than the normal pressure, find out the cause. If the oil pressure decreases due to the softening, eccentric wear or fracture of the pressure regulating spring during use, the spring preload shall be adjusted or the spring shall be replaced to restore the normal pressure.
6. Clutch maintenance
(1) Always check the free stroke of the pedal and the separation clearance of the three separation levers.
(2) If the release lever or release fork is seriously worn, replace it with a new one.
(3) Regularly check the lubrication of the bearing and inject grease if necessary. When the tractor works for 500 hours, remove the release bearing for cleaning. After cleaning, put it into a container filled with butter and heat it to make the butter penetrate. Take it out and install it after it solidifies. Note that the temperature should not be too high during heating.
7. Maintenance of hydraulic system
(1) Regularly check the height of the hydraulic oil level. 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 oil duct blockage or leakage at the seal, it is forbidden to scrub with cotton.
(3) Do not soak the rubber sealing ring with gasoline 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, oil cylinder, etc. are precision parts, which are generally not removed at will.
8. Electrical system maintenance
Check the connection of each conductor, which must be fastened and reliable, shall not be contaminated by diesel and engine oil, prevent contact with the hot part of diesel engine, and check whether the insulation performance of the conductor is good.
9. Battery maintenance
(1) Maintenance free batteries do not require special maintenance at ordinary times. Observe the display of hydrometer observation hole: green indicates sufficient power; Gray indicates insufficient power; Black means basically no power.
(2) When the battery observation hole is gray, supplementary charging is required; If a black display appears, replace the battery.
(3) The storage battery shall be stored in a clean, dry and ventilated place with a temperature of 0-40 ℃; Handle with care to prevent collision and do not put it upside down.
(4) The battery terminal and the power line connector shall be firmly connected to prevent the terminal from melting during startup. In order to prevent oxidation and corrosion of terminals, Vaseline shall be applied at the wiring terminals.
(5) Keep the external terminals of the battery clean. (6) Regularly check whether the output voltage of the generator meets the standard, and the voltage is (14.2 + 0.2) v.
(7) When charging, ensure smooth indoor air, keep away from open fire, and do not splash electrolyte on human body or clothes to avoid accidental injury.
(8) When the electrolyte of ordinary battery is insufficient, it shall be filled in time.
(9) During charging, the electrolyte temperature shall not be higher than 45 degrees. The charging current shall be halved or the charging shall be stopped to achieve the purpose of cooling, but the charging time shall be extended accordingly.
(10) At the end of charging, disconnect the power supply before disconnecting the power supply from the pole, so as to prevent fire or explosion caused by fire.
10. Maintenance of engine cooling system
(1) The engine coolant can be boiled tap water or antifreeze. Before starting, first check whether the cooling water in the radiator is full and whether there is water leakage.
(2) Regularly remove the scale in the cooling system to ensure the heat dissipation of the heat exchange surface.
(3) Regularly check whether the radiator core is blocked by weeds, dust, oil, etc.
(4) Check whether the performance of the thermostat is good on time, otherwise it will affect the circulation of cooling water and reduce the cooling effect.

Precautions for maintenance
During the daily use of large and medium-sized tractors, the maintenance methods of different models of tractors are different, and they should be maintained according to the correct instructions. According to the inspection requirements of large and medium-sized tractors, the following points should be paid attention to in the maintenance of large and medium-sized tractors:
1. Engine part: one is that the engine power and condition are normal. Since 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. In another case, the engine power decreases, and the engine shall be maintained.
2. Transmission part: if the clutch is unstable in combination, slipping, incomplete separation, difficult to shift, gear ringing, etc., the clutch must be maintained before busy, the friction plate shall be replaced in time, and the clearance between the main and auxiliary friction plates and the free stroke of the clutch pedal shall be adjusted.
3. Traveling part: the tire shall be intact, the air pressure shall be appropriate, the left and right shall be consistent, the steel ring shall be free of crack and deformation, the screws shall be fastened, the toe in of the front wheel shall meet the requirements, and the head shall 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 shall be checked frequently. If the braking effect is poor, it shall be removed for maintenance. Adjust the free stroke of the brake pedal to meet the regulations, return quickly, and have interlocking and self-locking devices. At the same time, the braking effect of the left and right wheels shall be consistent and the braking shall be effective.
6. Lighting part: frequently check and maintain the frequently used turn signal lamp, headlamp and horn.
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