Field Operation and Maintenance of Tractors and Farm Machinery II PDF

Field Operation and Maintenance of Tractors and Farm Machinery II -: Course Content Developed By :- Dr. Baldev Dogra Research Engineer Dept of Farm Machinery & Power Engg, PAU, Ludhiana :Content Reviewed by :- Dr. D. N. Sharma Retired Prof. and Ex-EO-cum-SE,CCS, HAU, H No. 155-A Hissar, Haryana INDEX Lesson Name Page No Module 1 LESSON 1. Familiarization with different makes and models of 4- 5-10 wheeled tractors Study of points to be checked daily, starting and safety checks Module 2. LESSON 2. Familiarization with service schedule, periodical service, 11-14. 10 hours service schedule. LESSON 3. Maintenance after 50 hours of tractor 15-21 operation LESSON 4. Maintenance after 125 hours of operation 22-24 LESSON 5. Maintenance after 250 hours of operation 25-29 LESSON 6. Maintenance after 500 hours of operation 30-32 Module 3. LESSON 7. Steering Geometry, Wheel Track 33-42 Adjustment LESSON 8. Fuel injection pumps–time setting, pressure adjustment 43-50 (nozzle opening) LESSON 9. Maintenance of electrical system of tractor Electrical 51-69 System (including starting motor, alternator and battery) Module 4 LESSON 10. Mould board plough- Adjustment, operation and 70-74 maintenance LESSON 11. Disc plough – Adjustment, operation and maintenance 75-78 LESSON 12. Adjustment and maintenance of disk 79-84 harrows LESSON 13. Adjustment and maintenance of seeding and planting 85-96 equipment LESSON 14. Adjustment, operation and maintenance of spraying 97-111 equipment LESSON 15. Adjustment, operation and 112-128 maintenance of harvesting equipment LESSON 16. Adjustment, operation and maintenance of threshing 129-136 equipment Field Operation and Maintenance of Tractors and Farm Machinery II Module 1 LESSON 1. Familiarization with different makes and models of 4-wheeled tractors Study of points to be checked daily, starting and safety checks Introduction: The tractor is a prime-mover which can be used for carrying out farm operations such as ploughing; harrowing, seeding, inter-cultivation, harvesting, transportation, land levelling and operating stationary machines (, irrigation pumps, threshers, chaff cutters, cane crusher etc.) All the machines require periodical servicing, maintenance and repairs for efficient and economical performance to stay in good operating conditions throughout working life. Although, most of the tractor manufacturers have appointed their dealers to provide operational know how, after sales and services of their products, yet, these are inadequate. Consequently, many machines are not properly maintained and are subjected to abnormal break downs, wear and tear and thereby reducing the effective life of the machines. Due to improper maintenance and servicing of the tractors, it has been found that many tractors have been rendered unserviceable within a short period of 5000 hours or even less. Seizures of engine, due to lack of oil in the sump and overheating of engine due to inadequate water in the radiator are common troubles. Damage of front wheel bearings and other moving parts due to improper lubrication and adjustments have also been seen often. A typical 4-wheel general purpose tractor is shown in Fig: 1. below: 5 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Let us familiarize ourselves with different controls of common four wheel tractor before deliberating more on its maintenance. 1. Tractor Assembly & Controls: 1.1 Power Trains: The power trains consist of engine, clutch, transmission (gear box), differential, final drives, axle shafts, wheels or tracks, steering & brakes. 6 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 1.2 Power outlets: The tractor power is made available for use through hydraulic lift, drawbar hitch, belt pulley & PTO shaft. (Fig: 4.) 1.3 Instruments and gauges: Most of the tractors are equipped with gauges and meters such as fuel pressure gauge, oil pressure gauge, water temperature gauge, hour meter, hydraulic pressure gauge and temperature gauge to indicate their operating conditions. Starter switch, light switch, horn button, fuel cut off controls is also fixed on many tractors (Fig: 5.). 7 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 1.4 Levers and controls: The tractor is also provided with throttle or accelerator lever/ pedal, clutch pedal/ lever, brake pedal/ lever, gear shift lever (main & auxiliary), steering wheel/ lever, hydraulic control, PTO pulley lever, differential lock/ pedal/ lever etc. to exercise control on different operations (Fig: 6.). Daily, starting and safety checks in tractor: Daily check points for starting and safety in tractor are: 1. Check fuel in fuel tank (is there enough fuel to complete the task). 2. Check coolant level in the radiator, or inspect cooling fins on air cooled models of tractor. 3. Check tire inflation pressure (refers to owner‟s manual for proper inflation of front and rear tyres for each job). 4. Check the condition of the tyres. Look for cuts, cracks and buckling. 5. Check the battery, cables and terminals and electrolyte level. 6. Check the transmission and hydraulic oil levels. 7. Check air filter elements, or the oil level in an oil bath type air cleaner. 8. Check the guards and shields to ensure that they are correctly installed and in good conditions. 9. Check operator‟s station. Be sure that it is clear of spilled fuel, oil, grease, crop residue, or loose objects. 10. Check the lighting system and ensure “Slow Moving Vehicle Emblem “is placed. Steps for starting a Tractor: 1. Make necessary checks before mounting on the tractor. 2. Mount the tractor from the left side of the tractor 3. Sit down on the seat 4. Make necessary checks after sitting on the seat 5. Move the hand accelerator to half of its total travel 8 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 6. Put the key into the main switch and turn it clockwise to warm the engine with heater (if required). 7. Turn the key further clockwise to crank the engine. 8. If the engine does not start within 10-20 seconds, repeat cranking of the engine after about 30 seconds. 9. Keep the engine running till it is warmed-up (for 2-3 minutes). 10. Disengage the clutch by pressing the clutch pedal. 11. Select suitable gear depending on speed and load requirement. 12. Release parking brake. 13. Increase engine speed by moving throttle lever clockwise and slowly release the clutch pedal, until the tractor moves off. 14. Take off the foot from the clutch pedal. 15. To change gear (up or down) reduce the engine speed by moving the hand throttle anti-clockwise. 16. Press the clutch pedal and let the tractor come to stop position (or crawling speed) Select the desired gear and repeat step 13. Steps for stopping a Tractor: 1. Reduce the engine speed (by hand throttle lever) to idling position. 2. Press the clutch pedal to disengage the clutch and put the gear shift lever in neutral position. 3. Release the clutch. 4. Stop the tractor (by applying brakes) 5. Pull the fuel shut-off knob/ stop switch till engine stops. 6. Withdraw key by turning it anticlockwise. 7. Engage parking brake. 8. Get up from the seat 9. Get down from the tractor from left side only. Tractor operation safety precautions a) General Points: 1. Run and maintain the tractor according to the operator‟s Manual of Tractor provided by the tractor manufacturer. 2. Check the working of all controls just after riding the tractor. 3. Release the parking brakes before starting. 4. Be alert and alert to drive it safely. 5. Whenever the tractor is stopped, even for a short while gear-shift lever should be brought to neutral position. 6. Always park the tractor with gear shift lever in the neutral position and with parking brake applied. 7. Operate the tractor smoothly; avoid jerky starts, turns and stops. 8. Drive slowly in difficult conditions. 9. Look at the rear while reversing the tractor. 10. Attend immediately to oil and fuel leakages. 11. Listen to the noise or sound in the engine, power transmission, etc., if any abnormal noise is noticed stop the tractor and investigate the causes. 12. Always keep a watch ahead of the tractor. 9 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 13. When stopped put the tractor out of gear, set brakes firmly. 14. Refuel the tractor only when the engine is cool, don't spill fuel and never smoke while refuelling. 15. Hitch implements only to drawbar or specified hitch points of the tractor. 16. Air intake assembly must be removed before raising the bonnet. 17. Beware of oily steps & slippery platforms. 18. Never drive after taking alcohol drink or drugs. 19. Never run the tractor engine in a closed shed or garage. 20. Don't permit unauthorised' persons to ride the tractor unnecessarily. 21. Never operate the hand accelerator of tractor from the ground. 22. Do not allow the tractor wheels to run over sharp objects. 23. Do not keep foot (ride) on the clutch and brake pedals while the tractor is running. 24. Do not sit or stand on the implement when the tractor is in motion. 25. Do not attempt the dual selector lever when the tractor is in motion. 26. Avoid spilling fuel over the engine. 27. Avoid overloading of the tractor during operations. 28. Do not get off or on the tractor when it is in motion. 29. Do not remove the radiator cap while the engine is hot. 30. Never leave the key in the starting switch. b) Points to be considered for safety on the Farm 1. Set the wheels as wide as required for the job. Use wider wheel track on slopes for stability. 2. Add weights on rear or front, as the case may be, for proper traction. 3. Keep P.T.O. and belt pulley shields in proper place. 4. Do not hook load at a point above the drawbar. 5. Reverse the tractor in low gear. 6. Driver tractor in low gears while overcoming obstacles like small bunds and ditches. 7. Draft control should not be used for raising or lowering the implements at the end of trip/ row. 8. Do not ride the drawbar of tractor during operation. c) Points for Road Safety 1. Obey the traffic rules while driving on road. 2. Drive slowly while making turns. 3. Use lower gear during up and down-hill driving. 4. Be careful during road crossing. 5. Stop the tractor on the left side of the road. 6. Keep brake pedals interlocked when driving on the road. 7. Give way to automobile vehicles. 8. While driving at night with trolley, do make extensive provision for lights at the rear as well as on the sides. 9. Never coast down- hill in neutral gear. 10. Never depress clutch pedal while driving down-hill. 11. Do not tend to turn sharply using independent brakes when travelling at high speeds. 12. Do not overload trolley. 13. Do not drive without rear-view mirrors 10 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Module 2. LESSON 2. Familiarization with service schedule, periodical service, 10 hours service schedule. It is uneconomical to manufacture a tractor with materials which will run for the designed service life. Scientists in developed countries have developed car engines which can be used for 0.2-0.4 million km without changing lubrication oil. Pre-greased, sealed bearings having lubrication enough for the designed lives are available. Car tyres have service life of 80,000 to 1, 00,000 km. So, day is not far when vehicles may not require any maintenance. However, at present the materials used in manufacturing of tractors wear off very fast if not properly lubricated, run at desired temperature and clean environment. Even if these are maintained, still many components are not designed to run for entire service life of the tractor. The life of lubrication oil used is increasing due to shifting to synthetic oils from petroleum based lubricating oils; still these are changed after 250 to 350 hours of engine operation. Slowly we are moving to manufacturing technologies and improvised alloys by adopting this short service (service at initial 50/100 hours of operation) is not required. Vehicle is just inspected for any loose nuts and bolts, clearances and deflections are checked and that is all done in short service or first service of tractor. However tractors manufactured with existing machine tools may require short service. Essentially it is maintaining lubrication, desired temperature and clean environment inside the tractor engine and other housing besides maintaining proper clearances, tightness and deflection of components of tractor for achieving desired service life. Clean environment inside the engine is achieved by maintaining intake system, i.e. 1) By cleaning pre cleaner periodically, 2) By maintaining correct level of right grade of oil in air cleaner and changing it as and when required 3) By cleaning the dry filter element periodically and changing it as and when required 4) By changing different filter elements at periodic service intervals. Desired temperature can be maintained by maintaining cooling system. This is accomplished by keeping correct level of water or coolant in radiator or dispenser bowl, by keeping radiator or fins clean. Desired level of lubrication is simply maintained by changing lubrication oils in different assemblies of tractor periodically along with filter elements. Other required activities are to keep the tractor clean and dry after a day‟s work, to tighten the loose nuts and bolts. By maintaining correct level of correct fluid in power steering 11 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II system, brake housing, steering housing, battery and fuel injection pump etc. wherever required. In short, tractors when put to use consume diesel, air and negligible quantity of mobile oil. There is some degree of wear and tear of all working parts which can be minimised with proper care and maintenance. Certain procedure has been laid down for this, which if followed will produce best results on tractor performance. These services needs have been classified into hours ranging from ten to several hundred hours of tractor use. These few very small activities can ensure that tractor runs for the designed service life. Service schedules generally maintain these conditions. Since, it is not necessary and possible also to carry out all above activities every hour. Activities required to be carried out at regular intervals to maintain these conditions are mentioned in service scheduled. Generally these are classified as 10, 50, 125, 250, 500, 1000 hour service schedule. The activities carried out in these schedules may vary marginally from one manufacturer to another for example ten hour service schedule list the activities to be carried out after a day‟s work at Farm. The list of activities to be carried out in 10 hour service schedule has been listed below. List of activities to be carried out in 10 hours service schedule: 1. Clean the tractor, if the tractor worked under dusty conditions & wash it with a swift jet of water to remove the dirt and wipe off with a dry cloth. 2. Inspect the tractor critically to ensure that no leakage is taking place at any point, take correct steps with the help of authorised service centre if the need be. 3. Check all the nuts and bolts for tightening properly on different parts of the tractor and replace the broken ones, if any. 4. Top up the fuel level in the fuel tank at the end of each days operation. This will keep your tractor ready for "next day and avoid condensation of water at the bottom of tank or in the fuel line. Fig: 1. View of fuel tank (Courtesy: Sharma and Jain) 12 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 5. Check and top up, if necessary crank case with mobile oil. Dip stick with low and full level mark is provided for the purpose. The oil level should be in the middle of these two marks. Fig: 2. View of checking and replenishing engine oil level (Courtesy: Tractor manual, Department of FPM, CCSHAU) 6.Clean pre cleaner. Check air cleaner oil level and if this level is less than the indicated mark or cut hole then top it. Fig: 3. View of oil bath type air cleaner (Courtesy: Tractor manual Department of FPM, CCSHAU) 13 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 7. Check up the water/coolant level in the radiator/ dispenser bowl and top if necessary. Do not allow water level to go below from the top of the radiator. Fig: 4. View of Radiator and its filling (Courtesy: Tractor Manual, Department of FPM, CCSHAU) 8.Check the belt pulley gear-box oil level when the pulley is in use and refill it to the plug level with transmission oil. 9. Check the front and rear type-pressure. In general, the pressure in the front tyres should be nearly 2 kg/cm2 and that in the rear tyres about 1 kg/cm2". Fig: 5. View of tyre pressure checking of tractor (Courtesy: Tractor Manual, Department of FPM, CCSHAU) Greasing of different points in tractor 14 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II LESSON 3. Maintenance after 50 hours of tractor operation Servicing after each 50-60 hours of tractor operation 1. Repeat the 10 hour service schedule 2. Maintenance of Tractor Battery: -Inspect the battery for loose terminals and electrolyte level.Wash the battery top with washing soda using warm water and grease the terminals with petroleum jelly to prevent corrosion. This in general includes the maintenance of battery which in turn refers to maintaining the battery electrolyte level and checking battery condition, battery frame and cable connections. Water from a battery solution is lost daily due to evaporation and mainly because of chemical action when it is being charged. If electrolyte level is not restored then battery plates are exposed to air and get corroded. Loss of water results in concentration of acid and breaking down of separators and plates and consequently loss of battery life. Battery liquid level should be maintained 10mm above 15 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II plates. Avoid over filling, as it might cause splashing through holes. It is important that battery is maintained at or near full charge. Sulfation occurs at less charge which decreases battery life. Secondly in cold weather battery capacity gets reduced. Battery condition is checked with the help of hydrometer and cell tester. Attention to the following points will help to get a long life from the battery. a) Keep the battery electrolyte level with distilled water. The electrolyte or battery solution should be about 10 mm above the plates. Never allow the level of battery solution drop below the top of plates. b) Never allow the voltage of the cells drop below a terminal voltage of 1.5V. c) The holes in the vent plugs must be clear. Vent holes allow the battery to breathe, especially when being charged. d) The terminal should be clean, tight and lightly coated with petroleum jelly. e) Connections should be kept tight. f) The battery should be securely held in its box. If it moves above, the case may get damaged. g) The top of battery should be kept clean & dry to stop leakage of electricity from one cell to another. Wipe out dirt, dust and any acid which splashed out of the battery. h) Keep the earth strap tight. This is lead from the tractor chassis to the earth terminal on the battery. i) Always charge the batteries to their full rated capacity. If the battery is not used for long periods, it should be taken off the tractor & stored in a cool shed. It should be charged once a month especially in winter. Testing of battery charge with hydrometer: Open battery cap, insert hydrometer nozzle in a cell, compress bulb and then slowly release the pressure to draw electrolyte into barrel. Adjust electrolyte level till float rides freely. Hold hydrometer vertically and take reading, take temperature of electrolyte and apply temperature correction. The specific gravity adjustment is made by adding or subtracting 0.004 for each 10° increase or decrease of temperature from 800F respectively. Add electrolyte to the cell. Flush hydrometer with clean water. Check the remaining cell in similar manner. Interpret result with the help of following table- Specific. Gravity of cell Interpretation 1.300 Electrolyte level low or battery over charge 1.225-1.1.280 Battery in good condition 1.225 Battery charge too low 16 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Testing with cell tester: Cell should indicate voltage of 2 volts or above when prongs of cell tester applied on positive and negative plates of the same cell. Checking battery frame and cable connections: If battery fitting clamps on the tractor are loose, battery is subjected to excessive vibrations and plates may get damaged. Loose terminals provide excessive resistance to flow of current and thus result in excessive damage to battery. Ensure that the cable connections are tight. 3. Check the fan-belt tension and adjust it if required: V-belts are designed to ride on the sides of pulleys. Too tight v-belts increase the wear of the belt and bearing. Too loose belt cause belt slippage which effects less engine cooling and battery charge. Due to belt slippage the alternator will not run at recommended speed to give satisfactory charging rate of battery.It is important to keep the belt clean from dirt and grease as these will soften belt and cause permanent damage.Fan belt tension can be measured with the help of wooden strip and a measuring rule by applying normal pressure with hand. This deflection should not exceed 20 mm or double the width of belt whichever is less. 4.Cleaning and servicing air cleaner: Clean and wash with kerosene/diesel the complete air cleaner. This refers to complete servicing ofair cleaner. A badly maintained air cleaner starve the engine of air. This will cause loss of power, fuel wastage and undue engine wear. If dirt in the oil bath gets settled up to 5 mm, it should be cleaned & filled with fresh engine oil. If dirt and dust is allowed to reach the engine cylinders, this will result in wearing-and damaging valve seats, piston rings and cylinder walls with subsequent loss in engine power. It has been observed that everyone litre of fuel requires about 8000 to 9000 litres of air to burn it completely. This air is drawn from the atmosphere which contains dust or dirt. This dirt is removed from the air by the air cleaner. Two types of air cleaners are in use: a) Oil bath typeair cleaner and b) Dry type air cleaner a)Servicing oil bath type air cleaner To service the air cleaner "Oil bath type" following steps should be observed: 17 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II a) Dismantle the air cleaner assembly completely. b) Remove pre-cleaner and clean it with air under pressure by passing air in the opposite direction of its normal flow. c) Remove the top screen and clean it with kerosene or diesel with the help of brush. d) Remove the used oil, clean with diesel and refill with fresh mobile oil to the level indicated. e) Clean air hose and air pipe with compressed air. f) Assemble the air cleaner assembly and attach it securely into its mountingon the tractor. b)Servicing of dry type air cleaner Followall the above steps for dry type of air cleaner except for "d" where element is cleaned by tapping or compressed air. It can also be cleaned with detergent if available. 5. Servicing of fuel supply system: This includes a) Check the fuel line for any leakage and clean it. b) Clean the sediment bowl and the screen. The purpose of a sediment bowl is to allow water to settle out and to catch particles of scale rust and other foreign material. Moisture is a problem is fuel for all type of engines, it is worst with diesel engine. This causes damage by promoting rust. So it is essential to clean it and following procedure is adopted a) Close fuel cock on fuel supply line b) Loosen the nut that holds the sediment bowl c) Remove bowl with twisting motion 18 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II d) Remove gasket. e) Remove strainer screen or filter f) Wash screen or filter element with diesel. g) Clean sediment bowl by washing with diesel or kerosene" h) Open fuel cock and observe flow i) Reinstall gasket, strainer and sediment bowl j) Tighten bowl against gasket k) Open fuel cock starts your tractor and check for leaks 6. Check and adjust the brakes for proper operation: As long as tractor speeds are slow uneven brake adjustment may not be too serious. But with higher tractor speeds available in most present day tractors uneven brake adjustment could easily damage the tractor. Two types of brakes are used in tractor. i) Shoe brakes & ii) Disc brakes When brakes are correctly adjusted it should be possible to press the brake pedals by approximately 3/4"(19 mm) before brakes are applied. This provides a running clearance to prevent the brakes continuously rubbing and overheating. Adjusting the brakes a) Check/see what provision is made for brake adjusting b) Jack up rear of tractor until both rear wheels are clean of the ground c) Release the brake interlock d) Tighten adjusting screw, adjusting rod through the adjustment screw as per match with the manual. e) Slacken the adjuster screw until the wheel revolves freely without shoe rubbing on the drum f) Adjust second brake in the similar manner g) Check to make sure that brakes are equalised tractor from jack test: Brake Test: - Lock both the brakes. Drive tractor on a hard and level surfaceat about 5-7 km/h speed. Apply brakes simultaneously. If the tractor slows/veers in either direction the brake on that side is adjusted too tightly or the opposite too slackly. Uneven, braking may be 19 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II rectified by adjusting the linkage of each brake in accordance with manufactures instructions until the tractor can be stopped without tending to slot in either direction 7. Check and adjust the engine clutch: A clutch will operate for longer period, unless' the driver has been operating the tractor with his foot resting on the clutch pedal. The clutch pedal should be adjusted to give a free play of 10-15 mm. The setting is obtained by adjusting the screw until the required measurement is obtained. Insufficient free movement prevents the clutch form engaging fully and lead to clutch slip, clutch overheating and rapid wear of the lining materials on the clutch plate. Once the clutch start slipping it will wear out very rapidly, it is very necessary to adjust it to avoid wear. Following steps are followed to undertake the correct free travel. Following steps are followed to undertake the correct free travel. Determine from your operator manual how much free travel is needed (10-15 mm) a) Measure the clutch free movement b) Locate means provided for this adjustment c) Loosen screw nut or bolts and move the pedal round the clutch release shaft to required adjustment 20 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II d) Check clutch pedal free travel e) Tighten lock nut so that it holds adjustment securely 8. Lubricate: Lubricate the following: a) Fan-hub bearing b) Throttle-control lever c) Engine-clutch-release bearing, and d) Alternator bearing 9. Check the water-pump (water body) for leakage and tighten or replace the packing, if required. 10. Loosen the vent plug and the drain-tap of the primary fuel filter and run off a small quantity of fuel in order to remove any water which might have accumulated. 21 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II LESSON 4. Maintenance after 125 hours of operation The 125-hour maintenance generally includes the following: 1. Repeating the activities carried out in 50h maintenance schedule 2. Changing crankcase oil 3. Replacing the oil filter 4. Servicing the crankcase breather 5. Maintenance of tractor tyres 6. Checking and servicing other parts of the tractor 1. Repeating the activities carried out in 50h maintenance schedule 2. Changing Crankcase Oil: The procedure for changing crank case oil is as under a) Keep the tractor on the level ground. Operate its engine until thoroughly heated up b) Remove drain plug c) Allow crankcase to drain for several minutes d) Change oil filter as described in steps (3) e) Put drain plug again f) Refill crankcase with new oil up to desired level g) Start engine and operate it for few minutes at low rpm h) Check oil leakage, if any i) Check oil level with dip stick and keep it at recommended level. Fig: 1.View of crank case oil (Courtesy: Escort Tractor) 22 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 3. Replacing the oil filter: It removes 1/20 to 1/30th solids from the lubricating oil. a) Locate oil filter b) Clean it with used cloth c) Loosen filter bowl and remove it d) Remove oil filter cartridge and discard it e) Clean inside of bowl with diesel f) Install new gaskets g) Install new filter unit h) Refill the filter bowl Fig: 3. View of oil filter (Courtesy: Escort Tractor 4. Servicing the Crank Case Breather: a) Remove the crankcase breather b) Wash filter element with diesel c) Shake out excess cleaning fluid d) Re-lubricate mesh with light crankcase oil e) Remove excess oil f) Reinstall the crankcase breather 5. Maintenance Tractor Tyres: a) Check Tyre inflation pressure in rear and front tyres with pressure gauge: b) Recommended tyre pressure are: 23 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Front - 1.1 to 1.25 kg/cm2 and Rear - 1.6 to 1.85 kg/cm2 c) Have proper tyre pressures & check with tyre pressure gauge d) Check Tyres for any cuts e) Check tor bruising, buckle etc 6. Checking and servicing other parts of the tractor Check the following and if needed put some lubricating oil. a) Generator/ Alternator bearing b) Distributor shaft Fig: 8. View of alternator used in tractor (Courtesy: Escort Tractor) 24 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II LESSON 5. Maintenance after 250 hours of operation The maintenance after 250 hours of operation service includes the jobs which are necessary for tractor to tune-up, which are as below: 1. Repeating the activities carried out in 125hours maintenance schedule 2. Valve clearance adjustment: Proper valve clearance is very important because: a) Valves give longer life b) Increases fuel efficiency c) Starting becomes easy d) Maximum power generation Fig: 1. View of valve system in tractors (Courtesy: Escort Ltd.) Recommended valve clearances for tractor engine are given in table below: Type of valve Recommended valve clearance Inlet valve 0.008" Exhaust valve 0.010 to 0.016" 0.004” (1 thou) = 0.1 mm Following steps may be followed to valve clearance adjustments: Steps for valve clearance adjustment: a) Check cylinder head bolts for tightness. 25 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II b) Slowly turn crankshaft until piston number 1, in the cylinder is at top dead centre (TDC) of compression stroke. c) Check clearance with filler gauge between valve stem and rocker arm of both the valves. d) If the clearance is not proper, loosen the adjusting screw nut and turn adjusting screw and check with filler gauge. Fig: 2. Viewhowingnder head for tightness. of proper and improper valve clearance (Courtesy Lab. Manual PAU Ludhiana) Fig: 3. View of removal of corrosion from battery terminal (Courtesy Lab. Manual by PAU Ludhiana) e) Determine which cylinder fires next. f) Turn crankshaft till the next cylinder in firing order is on compression. g) Adjust valves, following the same procedure as on No. 1 cylinder. 3. Checking the battery: a) Disconnect cable and ground strap from the battery terminals. b) Clean cable clamps. c) Remove dust and corrosion particles from battery terminals. 26 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II d) Brush soda and water mixture on top of the battery. e) Apply coating of petroleum jelly. f) Reconnect power cable and tighten properly. Fig: 4. View of Battery used in tractor (Courtesy: Tractor Manual FPM Deptt. CCSHAU) 4. Cleaning the sediment bowl and fuel filters: a) Remove the sediment bowl after closing the fuel supply. (Fig: 5.) b) Remove gasket, if any. c) Remove the filter or strainer and wash it with diesel. Pass the compressed air through it, so that dust and dirt can be removed more effectively. d) Clean sediment bowl also. Open fuel valve and check whether fuel is coming from tank is free from dirt or not, if not make a free flow: e) Assemble the sediment bowl and reinstall it over to the tractor. f) Change fuel filter elements as per recommendation of the manufacturer. 27 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Adjust tractor brakes: a) Check what provision is made for the brake adjustment. b) Jack up rear of the tractor until both the rear wheels clear the ground. c) Release brake interlocks and locks. d) Complete the preliminary arrangements for adjustment for first brake. Remove adjusting cover. e) Tighten adjusting screw, adjusting rod or adjusting nut. The brake is tightened by shortening the linkage between the brake pedal and the brake. It is tightened until there is 15- 20 mm of free travel on the brake pedal between its released position and the point where you can feel the brake starting to take hold. Fig: 7. View of brake system (Courtesy: Escort Tractor) f) Complete reassembling, or tightening of the locknuts to maintain adjustment. g) Adjust second brake in the same manner as explained above. h) Check to make certain that the brakes are equalized then lower tractor from the jacks. 5. Adjust engine clutch: Adjustment of foot operated clutches: To adjust the foot operated clutch proceed as follows: a) Determine from your operator's manual how much free travel in clutch pedal is needed. Recommendations vary from 15mm to more than 60mm. b) Check clutch pedal for free travel. 28 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II c) Locate means provided for clutch adjustments. d) Adjust linkage until clutch pedal has sufficient free travel. e) Tighten lock nut so that it holds adjustment securely. Adjustment of hand-operated clutches: To adjust the hand-operated clutch proceeds as follows: a) Check clutch lever adjustment to determine whether adjustment is needed. b) Disengage the clutch. c) Place gear shift lever in neutral. d) Remove hand-hole cover on clutch housing e) Turn clutch by handle until locking mechanism is on side next to hand-hole. f) Do the adjustment g) Reassemble it. 29 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II LESSON 6. Maintenance after 500 hours of operation The 500-hour maintenance operation includes the following jobs: 1. Repeating the activities carried out in 250 hours maintenance schedule 2. Front-axle adjustment 3. Servicing front-wheel bearings 4. Maintaining the cooling system 1. Front-Axle adjustment Toe-in adjustment The front wheels are slightly drawn in at the front side in such a way that the distance between the front sides of wheels is slightly less than their back side. The difference is known as toe-in and varies in the range of 4±2 mm. To get the desired font wheel toe-in, procedure followed is as under: 1. Bring the tractor on a levelled ground with front wheels in straight-ahead position. This can be done by moving the steering wheel from one extreme to another extreme position and then bringing it in the middle of its revolution. 2. Adjust the wheel alignment apparatus between the front wheels both at the front and the rear side and measure the distances on the scale provided. Adjust the toe-in if the need be. 2. Servicing Front-wheel Bearings A). Disassembling the Front-wheel bearings To disassemble the front-wheel bearing, proceed as follows: 1. Raise the front wheels off the ground. 2. Clean dirt from wheel and hub cap and remove hub cap. 3. Remove cotter pin and adjusting nut. 4. Remove thrust washer and outer bearing. 5. Pull wheel off the spindle. 6. If the inner bearing remained in the hub, remove it. 30 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II B). Clean the Front-wheel Bearings as below: 1. Wash bearings thoroughly. 2. Clean, hub, hub cap and spindle with solvent. 3. Remove solvent from the bearings and other washed parts. 4. Examine bearings for wear. 5. Examine grease-retainer ring and seal. Replace if damaged. C). Greasing & refitting of front wheel bearings: 1. Remove solvent from the bearings and other washed parts. 2. Examine bearings for wear. 3. Examine grease-retainer ring and seal. Replace if damaged. 4. Grease the bearing, hub and spindle. 3. Maintaining the Cooling system: Flushing or cleaning the cooling system Following procedure is followed for cleaning of cooling system: 1. Run engine until thoroughly warmed. 2. Completely drain cooling system while engine is still warm. 3. Close drain cocks. 4. Refill cooling system with water. 5. Add flush compound or cleaner. 6. Start engine and operate until normal operating temperature is reached. 7. Check external condition of cooling system for any leakage. 8. Completely drain the cooling system. 9. Refill with water and wash it & then drain it. 10. Refill it with appropriate coolant. Fig: 3. View of tractor cooling system showing the flow of water (Courtesy: Lab. Manual PAU Ludhiana) 31 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Fig: 4. View of pressurized radiator cap (Courtesy: Sharma & Jain) 32 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Module 3. LESSON 7. Steering Geometry, Wheel Track Adjustment Most of the general purpose tractors are provided with adjustable type front axles. The adjustable type front axle is provided to use with modern equipments like sowing, Planting, Crop protection and harvesting operation. It is a heavy duty assembly with larger diameter kingpin & bearings. The front axles are provided with seals to make it water proof for wet land cultivation. It has already been established that the driver can run the tractor in any direction he desires by controlling steering wheel of the steering system provided in the tractor. However, if the driver has to continually manipulate the steering wheel while doing field job or transporting on a straight road, he has to exert considerable force to turn the tractor on curves, he would be under quite a physical strain. Fig: 1. View of toe-in of front axle of a tractor (Courtesy: Escort Tractor) Front wheel alignment adjustments have been provided to eliminate these troubles and also to prevent early wear of the tyres. The front wheels have been installed on the front axle at a certain angle in accordance with the front wheel alignment. It is only when the various elements making up this angular relation are all correct that the steering wheel becomes stable, steering becomes less tiring, and tyre wear becomes less. Even if one of these elements should be missing, the steering wheel will remain unstable. The various elements of front wheel alignment mutually overcome each other's deficiencies and perform the following important functions: Minimize steering wheel turning effort 1. Stabilize the steering wheel. 2. Provide self centring to the steering wheel, 3. Prolong the life of tyres. 33 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Front Wheel Alignment: The following are the factors of front wheel alignment: a) Camber b) Caster c) King pin inclination d) Toe-in e) In tractor a, b & c items are fixed and cannot be altered, except Toe-in, which is adjustable. a) Camber: The front wheels that do the steering are installed tilted outward at top. This amount of tilt is called camber. (Fig: 2.). The front wheels tend to tilt outward at the bottom due to weight of the vehicles. Therefore, the wheels tend to pull out and to prevent this, camber is provided. Moreover, when camber is provided vehicle weight is impressed at the spindle root so that it contributes, together with the king pin inclination, toward reducing steering effort. The camber angle is normally from 1 to 3 degrees. (Fig: 2.) b) Caster: The king pin is installed with its upper part slightly tilted backward. This angle of tilt is called caster. The centre line of the tyre lies behind the point where the centre line of the king pin passes through the road surface. Because of this, the tyre rolling resistance causes the front wheel to 34 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II always trail behind, resulting in the front wheel to automatically follow the direction of vehicle progress. It is for this reason that when the steering wheel is turned, it returns automatically to straight ahead position when the hand is released. This is called caster effect. The caster is usually from 1 to 3 degrees. Caster produces the recovery force to return the front wheels to straight-ahead position. This also has a reverse effect of increasing the effort required to steer. To offset this there are vehicles made with zero caster. (Fig: 3.) c) King pin inclination: The upper part of the king pin (or line through upper and lower ball joint) is titled inward. This tilt is called king pin inclination, and is normally around 7 degrees. The front wheels swing around the kingpins when the steering wheel is turned. If king pin is not provided, the road resistance will cause the steering wheel to become unstable. By providing king pin inclination, together with camber the distance "e" (offset), between the wheel ground- contacting centre line and the point where the king pin centre line passes through the road surface will be made very small. Fig: 4. View of king pin inclination (Courtesy: Escort Tractor) 35 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II This makes the steering more stable. It also reduces the force required to rotate the front wheels around the king pins, making it easier to turn the steering wheel, particularly when the vehicle is stationary. When the steering wheel is turned, the presence of king pin inclination causes the front wheels to raise up the axle. For this reason, the vehicle weight presses down on the axle tends to return the wheels to straight-ahead position, restoring force is created. (Fig: 4.) d) Toe-in: The front wheels are not parallel to each other but have been made with the distance between the front parts slightly less than the distance between the rear parts. This state is called toe in. (Fig: 5.) As already related, the front wheels are provided with camber so that they tend to roll outward along the dotted lines "b". Assuming that the camber is the same at both sides, the wheels will no doubt roll together with the straight ahead vehicle travel, but the tyres will slip on the road surface while doing so. This will hasten tyre wear as well as making steering unstable. The toe in has been provided to prevent these troubles. Toe in =B–A. By providing toe in, the wheels will tend to roll inward along the dotted lines "c". This serves to counteract the force of camber tending to roll the wheels outward (along dotted lines "b") and allows the wheels to roll straight ahead without slipping. (Fig: 6.) The toe-in is designed as the difference of the distance between the front wheel tyre centre lines at the front end and that the rear end, and is usually from 6 to 10mm (0.24-0.39 in). The above wheel alignments have all been constructed to allow measurements or adjustments to be made by use of alignment gauges. 36 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 2. Adjustable front axle a) Introduction The front axle consists of a centre axle assembly, mounted centrally to the engine front support by means of a front axle support pin. This pin allows a certain amount of articulation about the centre point. The axle sections are attached to the centre axle by means of two bolts, nuts on each side. The holes used are positioned in such a way that the track of the axle can be varied in 4 in. (1220 mm) steps from 48 in. (1220 mm) to 76 in (1930 mm) The outer end of the axle sections accepts the front wheel spindles. These spindles are located by bushings on the axle section and at the lower end a thrust bearing is used to support the vertical thrust of the spindle of the axle section. The spindle itself acts as the "king pin" and hence the king pin inclination remains constant in relation to the axle beam. The top of each spindle has a key-way to locate steering arm, which is connected at the other end to the relative steering gear arm, by means of a drag link. 2.2 Wheel hub: The wheel hub is supported on the wheel spindle by two opposed taper roller bearings. A nut on the spindle is used to retain the outer cone and roller assembly. This nut provides adjustments for the bearing pre-load. (Fig: 7.) 2.3 Overhauling 1. With the tractor on firm and level ground applies the handbrake and blocks the rear wheels. Slacken the front wheel retaining by 1/4 turn. 2. Use a suitable jack or hoist to support the tractor with the front wheels clear of the ground. 3. Remove the wheel retaining nuts and remove the wheel and tyre assembly. 4. Unscrew the front hub grease-retaining cap. (Fig: 7.) 37 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 5. Remove the cotter pin locating the castellated nut. 6. Remove the castellated nut and washer. 7. Remove the front wheel hub assembly and the outer cone and roller assembly from the front wheel spindle. 8. Remove the inner cone and roller assembly from the wheel spindle. Remove the grease retainer. 9. Remove the bolt and nut retaining the spindle arm. Disconnect the drag link and/or track rod. 10. Remove the spindle arm from the spindle, if the spindle arm is tight, use Puller, EF 0800, Pulling Attachment, Tool No. EF 0501 and Shaft Protector. 11. Extract the key from the spindle and remove the dust seal.(Fig: 9. & Fig: 10.) 12. Extract the heel spindle and thrust bearing from the axle section. 2.4 Re-Assembly: 1. Pack the wheel spindle thrust bearing with recommended grease and install on the wheel spindle. 2. Install the wheel spindle into the axle section housing and ensure the spindle rotates freely in the bushes. 3. Install a new wheel spindle dust seal with the groove in the periphery of the seal nearest the base. 4. Install the key in the wheel spindle. Install the spindle arm on the wheel spindle locate the key. Ensure the spindle arm bolt hole is in line with the recess in the wheel spindle. Install the spindle bolt; lock washer and nut then tighten to the correct torque. Re- connect the drag link and tighten the retaining nuts to the correct torque. 5. Install the wheel hub grease retainer on the wheel spindle. 38 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 6. Install the front wheel inner bearing cone and roller assembly on the front wheel spindle. 7. Pack the wheel hub and bearings with recommended grease. Install the wheel hub on the wheel spindle. 8. Install the front wheel outer bearing cone and roller assembly on the front wheel spindle. 9. Install the hub-retaining washer on the wheel spindle, locating the tab with the keyway in the spindle. 10. Install the wheel hub-retaining nut. 11. Tighten the bearing-retaining nut to a torque of 2.8-4.2 Kg.m. 12. Rotate the hub clockwise 3-6 revolutions. 13. Further tighten the retaining nut to a torque of 6-8 Kg-m. (Fig: 10.) 14. Loosen the retaining nut by two flats. 15. Tighten the nut, if necessary, to the nearest position to allow insertion of a new retaining cotter pin. 16. Install the wheel and tyre assembly on the hub and 1 retain with the nuts. Tighten the nuts to the correct torque. 17. Remove the jack or hoist and the rear wheel chocks. 2.5 Adjustments: 1. Front Wheel Track Adjustment: The front axle consists of an inverted 'U' section centre axle assembly mounted centrally to the engine front support. The method of mounting consists of two support pin is attached to the mid-point of the centre axle assembly and the rear support pin is attached to the rear extension of the centre axle, the rear axle support pin locates in a bushing in the front axle 39 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II support. The front axle support pin bushing is incorporated into a bracket attached to the front axle support. The method of mounting limits the axle assembly to a radial movement about the support pin axis. This obviates the necessity of radius rods to locate the axle. The radial movement of the axle assembly is limited by the front axle support. (Fig: 11.) Table: 1. Track setting in tractor Track Setting Axle Bolt Mm Locations 1220 A C 1320 B D 1420 C E 1520 D F 1630 E G 1730 F H 1830 E G 1930 F H Outer axle section, consisting of an inverted „U‟ section with a tube to accept the wheel spindle welded to the outer end, is installed into the open ends of the centre axle assembly. The centre axle assembly and the axle sections are machined to provide a series of holes that will allow the track of the axle to varied in 102 mm steps between 1320 mm and 2030 mm. (Table: 1.) The outer end of the axle section accepts the front wheel spindle. The spindle is located in the axle section by bushings and at the lower end a thrust bearing is used to support the vertical 40 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II thrust of the spindle on the axle section. The spindle acts as the kingpin and hence the king pin inclination remains constant in relation to the axle assembly. The top of each wheel spindle is keyed to locate a spindle arm. Note: The track of the front wheels is adjustable from 1220 to 1930 mm in approximately 102 mm increments (Table: 1.). To obtain a front wheel track setting of 2030 mm it is necessary to reverse the disc of the front wheels at an axle setting of 1830 mm. It is not recommended that the wheels be reversed in the 1930 mm axle setting to give a resultant 2130 mm track as undue strain can be placed on components under high load and shock conditions. 2. Toe-in Adjustment: Follow following procedure toe –in adjustments 1. On flat level ground slowly drive the tractor in a straight-ahead position. Align the alignment mark with Spindle Arm. 2. Mark the each front wheel one foot above the ground. 3. Measure and note distance between the two marks on the front wheels. 4. Maintain the straight ahead position and move the tractor forward, so that the wheels rotate through 180º and the marks on the wheel face the rear at one feet height above the ground. 5. Align the marks, measure, and note the distance between the two marks. Note: If the measurement between the marks is more than the rear, it is toe-out and if the measurement between the marks is more than front, it is toe-in. Maintain toe-in between 0- 13mm. (Fig: 12.) 3. Wheel weights: In order to obtain sufficient traction for maximum performance in heavy draft operations and to counter balance heavy implements, cast iron wheel weights are provided for the front (if required) and rear wheels. Four holes are provided in the front wheel disc to enable front wheel weights to be attached to the wheel. These weights are to be mounted on the inside concave surface of the disc, using two bolts to retain each weight. Each weight is 20 Kgs. and a quantity of two weights is fitted to each wheel. Thus a total combined weight of 80 Kgs. can be mounted on the front wheels. 41 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 4. Front Axle Specifications: FRONT AXLE DETAILS ADJUSTABLE FIXED 1. Wheel track adjustment in 100.06 mm 1220-1930 mm - steps 2. Front Axle Geometry Axle Articulation 18º Camber Angle 2º 5º Castor Angle 5º 3º 30’ Kingpin Inclination 9º 6º 30’ Toe-in 0-13 mm 6-10 mm 3. Shims for End-float on Front Axle Thickness 0.05mm available 0.13mm 0.38mm 4. Tyre Pressure Front wheel Size – 6.00X16-8 Field Work 1.8 kg/cm² PR Road Work 2.29 kg/cm² 5. Recommended Grease Classification NL GI-2 or 3 5. Torque Specifications: Particulars Kgf-m Spindle Arm Clamping Bolt 6.21-6.90 Axle Section Bolt 18-22 Support Pin Bolt 19-22 Front Axle Support to Engine 25-30 Drag Link Ball Pin Joint 8-10 Drag Link Adjusting Clamp Bolts 1-1.5 Front Axle Trunnions Bracket 7.5-10 42 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II LESSON 8. Fuel injection pumps–time setting, pressure adjustment (nozzle opening) Fuel injection pump is heart of engine, it supplies fuels to the cylinders at desired pressure and time. Timing and pressure at which fuel is supplied to various cylinders is very important. Majority of the tractors and diesel engines are equipped with in-line fuel injection pumps. Time setting of one of such fuel injection pump is described as follows. Accurate fuel injection timing is set by fuel-cut-off method using swan neck pipe on number 1 delivery valve holder after removing the delivery valve spring and peg. 1. Remove the timing gear inspection cover and the timing pin from the flywheel housing. 2. Rotate the engine clockwise and observe the „O‟ mark on the fuel injection pump gear teeth. When the „O‟ mark on pump gear and intermediate gear teeth are about little away from meshing, insert the longer end of the timing pin in the flywheel housing as shown in Fig: 1. Now slowly rotate the engine clockwise to the point where the timing pin goes fully into the first hole in the flywheel and slides easily. After removing the inspection cover, pull the fuel shut off rod to the point where the control rod quadrant is visible and slightly forward of the middle position. Temporarily fix fuel shut off rod in this position and proceed with fuel injection timing as shown in Fig: 2. 43 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 3. Remove the 1st cylinder high-pressure pipe and the delivery valve holder after loosening the holder clamp. Remove the delivery valve spring, peg, and refit the delivery valve holder. Fit the swan neck pipes shown in Fig: 3. 4. Insert a piece of cloth in the timing inspection hole towards the intermediate gear to protect against any part or tool falling in the timing housing accidentally. Loosen the three-pump gear mounting bolts. 5. Rotate the pump shaft hub clockwise as shown in Fig: 4. 6. Keep operating the hand-priming pump. A stream of diesel will flow through the swan neck pipe. 44 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II A point will come when the diesel stream will reduce to drops. Carefully turn the pump shaft hub further clockwise till the point where drops fall at an interval of about 15 seconds.Holding the pump hub at this position, tighten the pump gear mounting bolts securely. Check, the zero on the gear of F I pump aligning with the cut of the hub as shown in Fig: 5. 7. Recheck timing by first taking out the timing pin and then turning the crankshaft anticlockwise.Drops will appear from swan neck pipe. Now turn the shaft clockwise till the drops reduce again to a drop every 15 seconds. Insert the pin in the flywheel hole to ascertain the correct timing to ascertain as shown in Fig: 6. 8. Complete the job and refit the Fuel Injection Pump Gear cover. Fuel Injection Timing of Rotary Pump (DELPHI-TVS ROTARY PUMP) Fuel injection timing setting of rotary pump can be done by following procedure (Fig: 7.& 8.). Observe timing mark on flywheel (Fig: 7.) and fit the same neck pipe on Ist delivery valve holder (Fig: 8.) 45 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II a) The pump is supplied, with drive shaft timed and locked at start of injection position. NOTE: i) At this position the key on the pump drive shaft will be at 7 O‟clock position viewing from pump drive end side as shown in Fig: 9. ii) At the above condition the spacer (1) provided below lock shaft screw (2) will be moving freely. The position of the spacer is as shown in Fig: 10. b) The engine is set to static timing position on flywheel (compression stroke on number 1 cylinder) as shown in Fig: 11. 46 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II c) Ensure “O” ring (3) properly seated on the pump flange as shown in Fig: 12. d) Fit FIP to engine plate and tighten the pump with 3 bolts (4) evenly to the specified torque to 27 Nm as shown in Fig: 13. e) Fit FIP coupling (5) on to the pump drive shaft (6) [Match FIP coupling key way with FIP drive shaft key (7)] as shown in Fig: 14. f) Fit FIP gear (8) on to the FIP coupling (5) as shown in Fig: 15. 47 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II NOTE: While positioning the FIP gear, ensure threaded holes (9) on FIP coupling is at centre of slots (10) on FIP gear as shown in Fig: 16. g) Fit FIP plate (11) over the FIP gear (8) and secure the FIP coupling, gear & plate with three bolts (12) and tighten the bolt to 27Nm torque as shown in Fig: 17. h) Unlock the lock shaft timing screw (2) and position to “run condition”. Refer Fig: 18. NOTE: At “run condition” tighten the lock shaft timing screw (2) to the recommended value of 12Nm torque. At the above condition, the movement of spacer (1) provided below lock shaft will be arrested. 48 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II (2) The position of the locked shaft screw is as shown in Fig: 19. & Fig: 20. i) Place the spring washer (13) on to the pump drive shaft (6) and tighten the drive shaft nut (14) to 80Nm torque. j) Rotate the crank shaft and ensure free rotation of gear as shown in Fig: 21. 49 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Low Idle and High Idle Speed Setting General Precautions a) Ensure setting the speed, only on a warmed up engine. b) Slacken the throttle link before setting the speed. (Fig: 22. &Fig: 23.) Low idle speed setting: a) Slacken the low idle screw locknut and turn the low idle screw to set low idle speed as specified. b) Tighten the locknut after setting the speed. c) Recheck the low idle speed after tightening the locknut. High idle speed setting: a) Slacken the high screw locknut and press the accelerator pedal fully down to set high idle speed as specified. b) Tighten locknut after setting the speed. c) Recheck the high speed after tightening the locknut. 50 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II LESSON 9. Maintenance of electrical system of tractor Electrical System (including starting motor, alternator and battery) 1. The Electric Power Generation and Storage System The electric power generation system is driven by V-belt, which gets drive from the crankshaft. It converts mechanical energy obtained from engine into electrical energy. Its main function is to recharge the battery. It also supplies electric current to the other accessories when engine is running. Generators can be DC (dynamos) or AC (alternators). Alternators can give current output up to 35 amps whereas dynamo output is limited to 12-14 amps. Regulator is also fitted on the tractor to regulate the current produced by the generator. If no regulator is provided, the current produced by the Alternator would be so much that it would damage the battery and the other electrical units of the Tractor. High electric current is permitted to flow by the regulator when battery is in a discharged condition or when the tractor electric unit is turned on. It helps in controlling the voltage produced by the Alternator when the battery is in a charged condition or when the electric units are switched off. The battery stores energy in chemical form. The reaction in the battery starts as soon as any circuit is completed by the action of a switch. It supplies current up to 400 amps, required to crank the engine and a limited current to the accessories. It is continually charged by the Alternator when engine is running. In every modern tractor an electric power unit is installed to produce and store electric energy that is delivered either at low voltage or in the form of high voltages. Electrical equipment fitted on tractors is required to operate without failure for very long periods with little attention. The power unit also provides an electrical means of cranking the engine, since the same is not capable of starting by itself. It automatically controls the voltage in the system. It also supplies power for lights and other accessories. The tractor electric system is quite simple in spite of the fact that it plays an important and multifarious role in the operation of the tractor. The electrical system may be classified under the following headings. 1. The Electric Power generation and storage system 2. The starting system 3. The lighting system The heart of the electrical system is the battery, it supplies current to the starting system, lighting system etc. The Alternator/dynamo keeps the battery charged. 51 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 2. The Starting System The starter is a DC motor gets a heavy dose of current from the battery. It is designed for intermittent service under heavy overload. The four poles are series connected and give high starting torque. When the circuit is completed by the solenoid switch, the pinion of the motor automatically meshes with the crankshaft ring gear. The reduction ratio between these two is 8:1 or 16:1. As the engine is started the pinion is thrown back to its initial position due to inertia effect. (Fig: 1.) 3. The Lighting System In the lighting system of tractor the lamps (bulbs) are used for warming purpose and lights for illumination purpose. The main lamps include the headlamps, the tail lamp, the number plate lamp, the tail lamps the direction indicator lamps and dashboard lamps.. The complete lighting circuit consists of a number of individual circuits for a single lamp or a pair of lamps each with its own switch, live connection and earth connection. The accessories like horn are connected parallel across the battery terminals. It has a separate switch. The dashboard gauges like oil pressure gauge, the temperature gauge do not have separate switch. These can be operated as soon as ignition switch is on. Battery The main purpose of the battery is to provide the electrical for operating the starting motor self starter. It also supplies the energy to operate the lamps and the other items of electrical equipment, some of which may be required when the engine is not running. The battery is an electro-chemical device. In the tractor battery employ “lead” and “sulphuric acid” as the active materials, and are known as “lead acid” batteries. Each battery consists of a number of cells. As the voltage of each cell, when fully charged, is slightly more than 2 volts, 6 cells are required for a 12 volt battery. The battery is a means of storing electrical energy in a chemical form. While the tractor is running normally the battery is automatically charged by means of the its charging system. 52 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Electrical energy is converted into chemical energy while the plates of the battery are being charged. When the battery is being discharged, the energy stored in the chemicals is released as electricity. A battery is said to be “discharged” when it is no longer capable of releasing electricity at a usable voltage. The tractor is provided with 12 Volt-80 AH / 88 AH maintenance free batteries. The negative terminal is earthed. The battery is connected in series. (Fig: 2.) Fig: 2. View of batteries terminals connected in series (Courtesy: Escort Tractor) The battery (Fig: 3.) has following three major functions to perform: a) To provide a source of current for engine starting, lighting and use of horn. b) To help control the voltage in the electrical system. c) To store the current produced by dynamo/alternator and to furnish the current when the electrical demands momentarily exceed the dynamo/alternator output. a) Construction of battery The battery is constructed in such a manner that each cell contains positive and negative plates alternately placed next to each other (Fig: 3.). Each negative plate is separated from the positive plate by a non-conducting porous separator, which prevents the plates from touching each other. All the positive plates are joined together to a post strap, forming a positive (+ve) group, and all the negative plates are joined together to a similar post strap, forming a negative (-ve) group. There is always one less positive plate than negative plates in each cell. The terminals are built up through the covers from the negative and positive group plate straps. Each cell has an opening at the top through which liquid electrolyte can be added when the filter caps are unscrewed. 53 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II b) Specific Gravity of Electrolyte of Battery The electrolyte in a fully charged battery is 1.220 to 1.250 times as heavy as pure water when both liquids are at the same temperature. Therefore, the specific gravity of electrolyte of a fully charged battery‟s 1.225 to 1.250 (For room temperatures). Table of specific gravity and its test: Battery Condition Specific Gravity Reading At Room Temp. Fully Charged 1.220 / 1.250 Half Charged 1.210 Fully Discharged 1.150 For Initially Filling of The Electrolyte 1.300 1. Battery Tests: a) Specific Gravity Test: 1. Check the specific gravity of a battery with a hydrometer 2. With the float in a vertical position, away from the side of the barrel, take the reading with eye at the level of the bottom of the curved portion of the liquid. 3. Specific gravity should not vary more than 0.025 points from cell to cell. 4. If the specific gravity is below 1.250 charge the battery and inspect the charging system to determine the cause of the low battery charge. (Fig: 4.) b) Periodical Maintenance of Battery 1. Remove the battery cover. Unscrew the vent plugs and ensure that the holes in each plug are free from obstruction. If not, any dirt should be removed by means of a piece of wire. Clogged plugs will cause pressure to build up in the cells due to the production of gases during charging and may result in damage. 2. Always keep the top of battery clean and dry. 54 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II 3. Examine the level of electrolyte in each cell, and if necessary, add distilled water to bring the electrolyte level just above the top of the separators to have the better performance and long life. 4. Check battery terminal poles and if badly corroded, clean with diluted ammonia. Also examine the connections and see that the terminals clamp bolts are tight. 5. Smear the battery with petroleum jelly. 6. Check and ensure that the earthing lead connection from the battery is making a good clean contact with the differential housing and that the securing nut is tight. 7. Check the specific gravity of the electrolyte in each cell to examine the state of charge of the battery. 8. Take the voltage test of each cell to cheek the condition of the cells. 9. Always see that the battery is charged properly by the current produced by alternator and avoid over charging the battery. The temperature should not exceed 51.7 degree C while fast charging, otherwise it may be severely damaged. 10. Under normal conditions of portion, water is the only chemical lost as a result of charging. Never add sulphuric acid to top up the battery unless the electrolyte level has been lost through spillage and electrolyte, if added must be of the correct specific gravity. 11. Battery should not be left in discharged state, as this will have a bad effect upon the plates and may ruin them completely. If the battery is left out of use, see that this is fully charged every fortnightly by a short charge to prevent by tendency of the plates to deteriorate. Maintenance free battery has an indicator to show the condition of the battery. Three color codes are given on the side of the indicator as follows: (Fig: 8.) Green: O.K White: Needs Charging 55 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Red : Add Distilled Water Starter Motor: The starter motor is a four-pole series connected DC Unit. The armature shaft runs on self- lubricated bearings. Drive engagement into the ring gear is made by energizing a solenoid, which actuates a roller clutch mounted on a helical spline formed on the end of the armature shaft. Only following drive engagement with the ring gear is the electrical supply made to the starter thereby ensuring a long life for the pinion and ring gear. Over speed protection for the starter armature is given by the roller switch. (Fig: 9.) Starter Motor Specifications Nominal Voltage : 12 Power Output : 4.2 H.P Max. HP Speed : 1370 R.P.M Stall Torque : 4.5 Kg-m Direction of Rotation : Clockwise Pinion No. of Teeth : 11 Module Pitch :3 56 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II a) Checking the Starter Motor: In the event of the starter motor failing to crank the engine at a high engine speed to allow it to start first check the state of charge of the batteries and the tightness and cleanliness of all the heavy duty electrical joints, including the engine to chassis earth lead. This usually solves most of the starting problems. If the slow speed cranking still persists or the starter motor fails to function at all, it is necessary to remove the unit from the engine. After its removal from the engine, a simple functional check can be made on the solenoid switch and the motor separately. To cheek the solenoid, connect the one lead from 12V battery to the supply terminal and the other battery lead to the body of the starter. This should cause the starter drive to move along the armature shaft. If an ammeter is put in series with the solenoid and a connection also made between the solenoid terminal and the top main terminal, than with 12V applied, the ammeter should read approximately 20 amps when the drive is fully engaged. A high current reading (40Amps) or failure to the drive to move at all means the solenoid is faulty and should be repaired. A direct light run check can also be made on the starter at this time. The starter motor should rotate freely at 5000-7000 rev/min and take a maximum current of 100 amps. If the motor fails to rotate, is sluggish or takes a high current, it should be thoroughly checked. During this test, the band cover around the starter yoke may be removed by loosening the single bolt fixing. Excessive sparking indicates that the commutator or the brushes may need attention. If just dirty the commutator can be cleaned with a petrol-moistened rag. Similarly the dirty or sticky brushes in the brush holder should be cleaned. If prior to removing the starter from the engine, starter rotates but the engine does not, this indicates either sticky or faulty roller clutch drive. The subsequent solenoid check will reveal whether the drive is sticky on the shaft and a simple head cheek can be made on the drive itself. It should be possible to freewheel the drive pinion in a clockwise direction, but the whole armature should rotate when the pinion is turned anticlockwise. If the pinion rotates freely in both the directions, the drive will need to be replaced as a unit. Similarly, if the drive slips under load, replacement is also necessary; this fault is however unusual. Drive Assembly Check Hold the drive assy. and inspect the pinion to ensure that it can be rotated in the direction of Starter rotation and that it should be locked in the opposite direction rotation. (Fig: 10.) 57 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II a) Armature Insulation Test Use 110 Volts AC mains 15W bulb with two probes, connect as shown in figure. Bulb must not glow when the probes are connected between any one of the commutated segments and Armature core. If the bulb glows the fault is with the insulation. Replace the Armature. (Fig: 11.) b) Field Coil Check Make sure the insulation is proper. Use 110 Volts AC mains ISW bulb with two probes. Connect as shown in fig. Bulb must not glow when the probes are connected to the field coil terminal and to the clean surface of the yoke. Locate the fault and rectify by re-taping or replacing the field coil assembly. (Fig: 12.) c) Solenoid Check Before testing the-starter to locate the defective component check the solenoid completely. To check the solenoid functions connect 12 Volts supply across the solenoid terminal and body of the solenoid. Check for complete movement of the drive. If not, engaging lever or solenoid could be defective. Locate the faulty component and replace. Alternator: Alternator provides a higher maximum output than the equivalent direct current generator and also increased charge rates at lower engine speeds. Unlike a direct current generator, the alternator does not require a commutator and can be run safely at higher speeds. (Fig: 14.) 58 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II The alternator is mounted at the front of the engine being belt driven from the crankshaft pulley. (Fig: 15.) The alternator comprises principally 1. Rotor 2. Stator 3. Rectifier Pack 4. Regulator / Brush Box 59 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II a) Rotor The rotor and brush gear provide the magnetic field of the alternator unlike a direct current generator where the field is stationary. The rotor is belt driven from the engine through a pulley keyed to the rotor shaft, which runs in heavy- duty sealed ball race bearings. An integral fan, adjacent to the pulley, draws cooling air through the alternator. Current is supplied to and returned from the rotor field coil via two carbon brushes, which bear against slip rings on the rotor shaft. As current passes through the copper wire of the rotor field coil a magnetic field is produced and contained within an armature formed into pole shoes. The configuration of the pole shoes ensures concentration of the magnetic field. b) Stator The stator contains the windings into which current is induced by the revolving magnetic field of the rotor. Main components of stator are shown in Fig16. The stator is fabricated from laminations of thin steel pressings onto which three separate wires are wound. The laminations are specially formed to concentrate and collect the magnetic field. During each complete revolution of the rotor, all three stator windings have induced currents passing first in one direction and then the other; in other words a 3-phase alternating current. Because alternating current is generated in a series of pulsations, the rotor features six pairs of poles to provide an overall smoother output. For every revolution of the rotor the output characteristic of each stator winding completes six cycles. 60 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Alternating current (AC) is unsuitable for charging the battery, which requires pure direct current (D.C.). Therefore, the three-stator windings are connected to a rectifier pack, which rectifies or converts the alternator output to direct current. Regulator and Brushes: The regulator controls and maintains the alternator output voltage at a safe working level. The regulated voltage level is established in manufacture and cannot be adjusted in service: The regulator components are housed in a sealed assembly, which is integral with the alternator brush box. Individual brush box and regulator components are not serviceable and have to be replaced as a complete assembly. Alternator Operation: When the start key switch is turned on, an amount small current flow from the battery through the rotor field windings. The circuit is made via the charge indicator warning light, alternator terminal IND, the rotor field winding, the alternator regulator and ground. At this stage the warning light is illuminated and the rotor partially magnetized. When the engine is started and the partially magnetized rotor revolves within the stator windings a 3- phase alternating current is generated. A constant portion of the generated current is converted to direct current by the three field diodes incorporated in the rectifier pack. This direct current is fed back to supplement the current flowing through the rotor field winding. This action results in an ever-increasing magnetic influence of the rotor along with an associated rapid rise in generated output current and voltage. During the rise in generated output voltage (reflected at terminal IND) the brilliance of the warning light is reduced and when the voltage at the IND terminal equates to that at the battery side of the warning light the lamp is extinguished. The voltage continues to rise until the predetermined regulated voltage level is reached. In the event of drive belt breakage the voltage will not build up within the alternator and so the charge indicator light will remain on to indicate failure. 5. Trouble Shooting Chart Battery Symptom Probable Cause Remedy Low specific gravity of Battery worn out Replace after test confirm diagnosis. electrolyte in Cells Infrequent driving. Charge by driving or by small bench charge periodically. Loose fan belt Tighten / replace belt Low open Circuit Voltage setting in Set regulator correctly. 61 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Regulator. Leakage Currents. Check, clean battery top. Short circuit in wiring. Replace faulty wiring Plates sulphated. Recover by sulphation treatment Loose terminal clamps, corrosion. Clean terminals clamps, Tighten clamps Abnormal rise in Plates sulphated. Recover by sulphation. temperature during charge (generally with Short circuit in cells Repair / replace faulty cells abnormal premature High charge current Lower to normal value. gassing) Abnormal color of Contaminated electrolyte Dump acid, wash inside of cells with plates: separators distilled water, recharge with new bleached darkened; electrolyte white spots on top of Low electrolyte levels. Top-up plates Sulphated plates. Recover by sulphation Excessive topping Overcharging Check, correct regulator setting required. For electrical system of tractor Symptom Probable Cause Remedy Several or all lights Battery discharged. Check battery and charge or renew. do not illuminate Battery discharged. Loose or defective battery cable Inspect, clean and tighten connections connections. Loose harness connectors. Check and ensure connectors securely engaged. Fuse (s) burnt out. Inspect and renew, check circuit before reconnecting power. Faulty wiring. Check lighting circuit wiring and repair or renew. Defective light switch. Check and renew. Several light bulbs burnt out due Check and renew voltage regulator. to defective voltage regulation. 62 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Individual lights do Burnt out bulb. Check and renew. not illuminate Burnt out bulb. Defective or corroded bulb Inspect, clean or renew. contacts. Fuse burnt out. Inspect and renew, check circuit before reconnecting power. Loose or broken wires. Inspect, secure, repair or renew wiring. Poor ground connection. Inspect, clean and tighten ground connections Lights burn out Loose or corroded wiring Inspect, secure, repair or renew wiring repeatedly connections. Loose or corroded Loose bulb or lamp mounting Inspect, tighten or renew. wiring connections. bracket. Faulty Voltage regulator. Check and renew voltage regulator. Plough lamps Side lights switch not turned on. Ensure sidelights are illuminated. inoperative Side lights switch See "Individual lights do not See "Individual lights do not illuminate". not turned on. illuminate. Flasher lamps do Fuse blown. Inspect and renew, check circuit before not illuminate reconnecting power. Fuse blown. Flasher lamps do Flasher unit inoperative Check and renew. not illuminate Flasher unit may be by passed by Flasher unit interconnecting terminals. This enables inoperative circuit continuity to be checked. Flasher switch inoperative. Check and renew. Defective wiring or connections. Inspect circuit, clean and tighten connections or renew wiring. Individual flasher Burnt out bulb. Check and renew. lamp does not illuminate. Corroded or loose bulb contacts. Inspect, clean, tighten or renew. Burnt out bulb. Poor ground connection or Inspect, clean and tighten connection, damaged wiring. repair or renew wiring. Turn indicator pilot Faulty bulb (s). Check and renew. bulb (s) Defective flasher unit. Check and renew. 63 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II inoperative. Faulty Wiring or connections. Inspect, clean and tighten connections Faulty bulb (s). or renew wiring. Main flasher lamp bulb contacts Inspect, clean, and tighten connections or ground connection corroded and ground connections. (failing to draw full current). Instrumentation Warning lights and Faulty key start switch. Inspect and check. gauges inoperative Faulty key start Fuse (s) burnt out. Inspect and renew, check circuit before reconnecting power. switch. Loose or broken wiring. Inspect circuit, tighten connections or renew wiring. Starting System Engine will not Battery discharged. Check battery and charge or renew. crank and starting motor relay or Key start switch, safety starts Check circuit and repair or renew faulty switch, relay or solenoid components. solenoid does not engage inoperative. Battery discharged. Starting circuit open or high Check circuit connections and repair or resistance. renew faulty wiring. Engine will not Battery discharged. Check battery and charge or renew crank but starting motor relay or Defective starting motor Check, clean and tighten connection solenoid engages connections or loose battery Battery discharged. connections. Starting motor faulty. Inspect, repair or renew. Relay or solenoid contacts burnt. Renew relay or solenoid. Engine seized. Check engine crankshaft free to turn. Starting motor Defective starting motor drive Inspect and repair or renew. turns but does not assembly. crank engine Defective solenoid or pinion Inspect and repair or renew. Defective starting motor drive engagement levers. assembly. Defective flywheel ring gear. Inspect and renew. Engine crank slowly Discharged battery. Check battery and charge renew. 64 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II Discharged battery. Excessive resistance in starting Check circuit connections and repair or circuit. renew faulty wiring. Defective starting motor. Inspect and repair or renew. Tight Engine. Investigate cause and effect repair. Charging System Battery low in Loose or worn dynamo / alternator Check & adjust tension or renew. charge or drive belt. discharged Loose or worn Defective battery will not accept Check condition of battery and renew. dynamo / or hold charge. alternator drive belt. Electrolyte level low. Check, fill and charge. Excessive resistance due to loose Check, clean and tighten circuit charging system connections. connections. Defective voltage regulator. Check and renew. Defective dynamo / alternator. See dynamo / alternator trouble shooting guide. Alternator charging Defective battery. Check condition of battery and renew. at high rate (battery consumes Defective voltage regulator. Check and renew. more electrolyte) Defective alternator. See alternator trouble shooting guide. Defective battery. No output from Alternator drive belt broken. Renew and tension correctly. alternator Alternator drive Loose connection or broken Inspect system tighten connections and cable in charging system. repair or renew faulty wiring. belt broken. Defective voltage regulator. Check and renew Defective alternator. See alternator trouble shooting. Intermittent or low Alternator drive belt slipping. Check and adjust tension or renew. alternator output Alternator drive Loose connection or broken Inspect system tighten connections and cable in charging system. repair or renew faulty wiring. belt slipping. Defective voltage regulator. Check and renew Defective alternator. See alternator trouble shooting. 65 www.AgriMoon.Com Field Operation and Maintenance of Tractors and Farm Machinery II ALTERNATOR Alternator light Faulty rotor slip rings or brushes Inspect and repair or renew. dims and / or battery low Faulty External charging circuit Inspect system clean and tighten connections. connections. Warning light goes Faulty rectifier or rectifying diodes. Check and renew. out-becomes brighter with Defective voltage regulator. Check and renew. increased speed

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