John Deere 760 Tractor Service Manual

SERVICE MANUAL John Deere Dubuque Works SM-2075 (Jun-67)

SERVICE MANUAL JOHN DEERE JD760 TRACTOR CONTENTS Section Description and Operation ............................................ 10 Specifications ..................................................... 20 Periodic Services .................................................. 30 Engine Tune-Up and Tractor Adjustments .................................. 40 Preliminary Procedure for Major Service .................................. 50 Basic Engine. ..................................................... 60 Engine Lubrication System ............................................ 70 Cooling System .................................................... 80 Fuel System. ...................................................... 90 Transmission Clutch ................................................ 100 Syncro-Range Transmission ........................................... 110 Differential. ...................................................... 120 Final Drive. ...................................................... 130 Power Take-Off (PTO) ............................................... 140 Electrical System .................................................. 150 Seat ............................................................ 160 Front Axle ....................................................... 170 Wheels, Tires, and Weights. ............................................ 180 Hydraulic System. .................................................. 190 Hydraulic Pumps. .................................................. 200 Power Steering, ................................................... 210 Power Brakes. .................................................... 220 Selective Control Valves, ............................................. 230 Drawbar Assembly. ................................................. 240 Trouble Shooting, .................................................. 250 Special Service Tools. ............................................... 260 Copyright 1966 DEERE&COMPANY Moline, Illinois All rights reserved SM-2075 (Ott-65) Litho in U.S.A.

2 Tractor, JD760- Introduction TO THE JOHN DEERE SERVICEMAN This service manual contains maintenance instructions for John Deere JO760 Tractors. In- cluded are complete instructions for removal, disassembly, inspection, repair, assembly and installation of the major parts and assemblies of the tractor. In addition, the manual contains brief descriptions of the more complicated systems of the tractor, and tells how they operate. In Section 20, “Specifications, *’ dimensions of many new wearing parts are given as an aid in determining when parts replacement is necessary. Section 260, “Special Service Tools, ” describes the tools necessary for proper serv- icing of JD760 Tractors. Section 40, “Tune-Up and Adjustment, ” contains instructions for performing the services necessary to help the tractor perform efficiently and economically after it has been in the field for some time. This manual was planned and written for the Service Department; its place is in the shop. Use the manual whenever in doubt about correct maintenance procedures. Use it as a text book for training new Service Department personnel who are unfamiliar with John Deere Tractors. Daily use of the service manual as a guide for any and all service problems will reduce error and costly delay to a minimum and as- sure you the best in finished service work. In many instances your customer’s confidence in your work will be improved when he sees you using the service manual. He knows you are following approved maintenance procedures and making proper adjustments. There is no guess- work when you use the manual. John Deere JD760 Tractor SM-2075 (Ott-65) Litho in \U.S.A.

Group 5 DESCRiPTI Fig. IO-5l-John Deere JD760 Tractor INTRODUCTION The John Deere JD760 Tractor is designed to operate heavy industrial equipment. The tractor is the prime mover for the John Deere JD760 Scraper, a rugged, compact, effi- cient dirt-moving unit. The operator’s station is at the side of the tractor, a convenient position for better ob- servation of the work being performed. The tractor is equipped with a powerful John Deere engine developing 143 net engine flywheel horsepower. 10-5-l The features of the tractor are described briefly in the paragraphs which follow. Full descriptions of each of the components are given in the various sections throughout this manual. SERIAL NUMBERS Each engine is identified by a serial number located on the right hand side of the cylinder block immediately behind the alternator. The engine serial numbers given in this manual are the numerical serial numbers indicated in the following example: SNM33RO Pl~O~ R Numerical Serial Number SM-2075 (Ott-65) Litho in U.S.A.

10-5-2 Tractor, JD760- Description and Operation Description The tractor serial number is located at the rear center of the transmission case. The tractor serial numbers given in this manual are the numerical serial numbers indicated in the following example: SNT373R 012000 R L I Numerical Serial Number NOTE: When ordering engine OY tractor parts, record all the digits in the serialnumber. For brevity, when serial numbers are given in this manual any zeros which appear before the first significant digit are omitted. MODEL NUMBERS The fuel injection pump, main hydraulic pump, selective control valve housings, and alternator each bear a model number. ENGINE The tractor is powered by a variable-speed, full diesel engine. The engine develops up to 143 net engine flywheel horsepower at 2200 r-pm. The engine is a six-cylinder in-line four- stroke cycle engine. The cylinder liners are the wet sleeve type and the crankshaft bearings are the precision insert type. Lubrication system has a full-flow filter with a replaceable element. The engine oil cooler is designed to cool the oil to a safe operating temperature. A liquid-seal impeller type crankcase venti- lating pump draws clean air from the air clean- er and circulates it throughthe engine for crankcase ventilation. COOLING SYSTEM The pressure type cooling system has acen- trifugal pump to provide continuous circulation of engine coolant. Proper engine temperature is maintained by two thermostats in the upper water manifold. When the thermostats are closed, thesystem is designed to permit circulation of the coolant through the engine without passing through the radiator. This feature results in the engine SM-2075 (Ott-65) Litho in U.S.A. reaching operating temperature in a shorter length of time. When the engine reaches operating temperature, the thermostats open to control the flow of coolant through the radiator to maintain a constant operating temperature. FUEL SYSTEM A 72 U.S. gallon fuel tank is an integral part of the fuel tank housing at the right side of the tractor just ahead of the rear wheel. A fuel pump driven by the camshaft assures a constant supply of fuel to the injection pump. Two replaceable micronic filtering elements are connected between the fuel pump and the in- j ection pump and filters the diesel fuel before it enters the injection pump. Fuel is injected by a distributor-type solid injection pump through high-pressure nozzles into the cylinders. A common pipe connected to each nozzle returns leak-off fuel from the nozzles to the fuel tank. ELECTRICAL SYSTEM The tractor is equipped with a 24-volt alternator with regulator to furnish current for the electrical load and to maintain charges in four B-volt batteries, connected in series. This system is of the conventional grounded type, using negative grounded circuits. A 24-volt starting motor with a coaxial, sole- noid-shifted drive pinion is used to crank the engine. Lighting circuits are 24-volt withtwo 12-volt loads in series in each circuit. All lamps are in pairs with exception of the tractor red taillamp which is in series with a resistor. Current at 12 volts is furnished for the accessory circuit by two of the four 6-volt tractor batteries. CLUTCH ASSEMBLIES The heavy-duty, two-plate, spring-loaded, transmission clutch is located in a recess at rear of the engine flywheel. It is operated by a pedal (hydraulically assisted) located to the left ofthe operator’s platform. The clutch-operating cylinder is connected to an accumulator whichsup- plies energy to operate the clutch, should the engine be stopped or hydraulic pressure fail.

Tractor, JD760- Descrintion and Oneration 10-S-3 The PTO clutch is of the multiple wet-disk type and is hydraulically actuated. It is operated by a lever to right of operator. TRANSMISSION The Syncro-Range transmission, which contains constant-mesh, helical-cut gears, has four shift ranges. Three of the ranges have low, high, and reverse gears. The fourth range has low and high gears only. Thus, eight forward gears and three reverse gears are provided. Shifting is accomplished by means of two levers located to the left and forward of the instrument panel. The left-hand lever is used to select the desired range. The right-hand lever is used to select high, low, or reverse gear within the range. The high, low, and reverse gear shifting is synchronized and can be accomplished while the tractor is moving. While the shift between ranges is of the collar shift type and is normally accomplished withthe tractor stopped, it can be accomplished while the tractor is on the move by proper use of the “double clutching” technique. DIFFERENTIAL AND FINAL DRIVE A conventional spiral bevel ring gear and pinion drive is used in the tractor. A planetary gear assembly provides the final gear reduction in the drive gear train. This design reduces strain on the gear train. A lock located in the differential assembly, enables the operator to lock the differential. This causes both rear wheels to turn at the same speed, moving the tractor under conditions where one drive wheel has lost its traction. POWER TAKE-OFF (PTO) The tractor can be furnished with a right- angle, vertical PTO for use with the elevating scraper. At 2200 engine rpm, the vertical PTO operates at 1128 rpm. The tractor can be obtained with a lOOO-rpm horizontal PTO. At 1900 engine rpm, the horizontal PTO operates at 1010 rpm. DRAWBAR The tractor is equipped with a heavy-duty fixed drawbar for attaching towed equipment. FRONT AXLE The tractor is equipped with a heavy-duty, fixed tread front axle. The front wheels are truck-type rims bolted to hubs mounted on ta- pered roller bearings. Front wheel tread is 69-l/4 inches. REAR WHEELS Heavy-duty rear wheels are attached to the rear axles with no provision for tread width adjustment. Rear wheel tread is 72 inches. SEAT The tractor is regularly equipped with a de- luxe suspension seat. This seat contains a steel compression spring and a shock absorber to provide “Float Ride” suspension. The seat has a flexibly-mounted, padded back rest and semi-circular foam padding which sur- rounds the back of the operator. S&I-2075 (Jun-67) Litho in U.S.A.

10-5-4 Tractor, JD760- Description and Operation Description HYDRAULIC SYSTEM The tractor hydraulic system is pressurized by a constant-running, variable displacement, hydraulic pump. The pump is mounted below and ahead of the radiator. It is driven at engine speed by the engine crankshaft. The hydraulic pump supplies oil under pressure to operate the power steering, power brakes, transmission clutch, differential lock, up to three remote hydraulic cylinders (if so equipped) or, the brakes and operating cylinders of trailing equipment. The hydraulic system is constant pressure, closed center, and “live”; that is, it operates when the engine is running, whether the tractor is moving or not. STEERING Hydraulic power steering is regular equipment on the tractor. Movement of the steering wheel actuates a steering valve which directs a flow of pressure oil to two steering cylinders which turn the front wheels. Should the hydraulic system lose pressure, the tractor can be steered manually. POWER BRAKES The power brakes are operated by pedals located at the right side of the operator’s platform. The brakes can be applied independently or si- multaneously. The brake pedals can be locked together for simultaneous operation if desired. The hydraulically actuated, disk type brakes operate in oil. NOTE: The tractor brake pedals should always be locked together when operating the rock wagon OY scraper unit except when it is neces- savy to use individual braking to make extremely shovt tuvns. On scraper units, the scraper power brakes are operated by a lever located at the left of the steering column, just under the steering wheel. On tractors with Athey Rock Wagons, this lever is the brake selector lever and controls the operation of the rock wagon brakes. CAUTION: Always apply the scraper brakes f Ir st when stopping the unit. Then, if necessary, use tractor brakes to assist. Using tractor brakes alone can be dangerous due to possible jackknifing of the unit. A brake accumulator, charged with dry nitro- gen at 500 psi pressure, is connected to the brake systems and transmission clutch operating cylinder. The accumulator stores energy for operation of brakes and clutch for several applications after the engine is stopped or if the main hydraulic pump should fail. Units with the selective control valve levers running crosswise to the tractor also have a hydraulic oil accumulator that is connected to the selective control valve circuits. The hydraulic oil accumulator is also charged with dry nitro- gen at 500 psi pressure. SM-2075 (Jun-67) Litho in U.S.A.

Operation Tractor, JD760- Description and Operation 10-10-l STARTING CONTROLS Group 10 OPERATION Fig. IO-IO-I-Engine Starting Controls Figure 10-10-l illustrates the starting controls for the engine. PRE-STARTING INSPECTION 1. Check the engine crankcase oil level. 2. Check the radiator coolant level. 3. Check radiator hose and connections for leaks. 4. Make sure the fuel shut-off valve for the fuel tank is open. 5. Visually inspect tractor and tires for any irregularities which might affect operation. STARTING THE ENGINE 1. Place the Hi-Lo (right-hand) gearshift lever in neutral (N) position. 2. Move hand throttle lever to a position l/3 of the way forward. 3. Turn key switch to the on position. The oil pressure indicator lamp should light. If it does not, turn the key switch off and determine the cause. See Section 150. 4. At temperatures below 40” F. use the cold- weather starting fluid adapter (page 10-10-2) and other cold weather starting aids as required. 5. Press the starter button to crank the engine. If the engine does not start the first time, wait a minute or two before trying again. If it does not start after four attempts, see Section 250 of this manual. NOTE: Do not hold the starter button in “wank” position for moye than 30 seconds at a time. To do so may overheat the starter. 6. As the engine begins to run, check to see that the oil pressure light goes out. If not, stop the engine and determine the cause. See Section 150 of this manual. Check ammeter for alternator charging rate. If no charge is shown, refer to Section 150 of this manual. AFTER-STARTING INSPECTION 1. Make sure that oil pressure light goes out. 2. Be sure ammeter shows charge. 3. Check for water, oil, or hydraulic leaks. 4. Check the transmission hydraulic system oil level. SM-2075 (Jun-67) Litho in U.S.A.

10-10-2 Tractor, JD760- Description and Operation Operation COLD WEATHER STARTING COLD WEATHER STARTING FLUID ADAPTER Fig. IO-IO-2-Starting Fluid Adapter The tractor is equipped with an adapter (Fig. 10-10-2) to inject atomizedstartingfluidintothe engine air intake system, The starting fluid, which aids fuel combustion, is furnished in pres - surized cans. To use the can of starting fluid, remove the safety cap and plastic spray buttonfrom the can. Remove the cap from the adapter and position the can under the adapter. To inject starting fluid, push up on the can. CAUTION: To avoid damage, turn engine with starter one or two revolutions before injecting startlng fluld. InJect starting fluld only while the engine Is turnlng. Relax pressure on the canbetween “shots”of starting fluid. Stop injecting fluid after the engine starts. If the engine begins to die during the first few minutes of operation, inject another “shot” of fluid. When the engine is operating satisfactor - ily, remove the can from the adapter and replace the safety cap on the can. Be sure to install the cap on the adapter when it is not inuse. This will prevent dust from being drawn into the engine. Store starting fluid cans where they will not be subject to extreme cold or warm temperatures. For best results, store fluid at room temperature. CAUTION: Ether startlng fluld Is highly flammable. ADDITIONAL BATTERIES Starting the engine in cold weather can be facilitated by connecting an additional 24 volts of booster batteries in parallel with the tractor batteries. Ri i-’ / / Fig. IO-70-3-Battery Connections Use jumper cables to connect the positive (+) terminal of the booster battery assembly to the positive terminal of the tractor battery assembly (Fig. 10-10-3). To make the last connection or the first disconnection at some point away from the battery, connect the negative (-) terminal of the booster battery to a good groundon the tractor frame away from the battery. Never connect jumper cable to pipes or thin sheet metal. CAUTION: Gas glven off by batteries Is ex- ploslve. To avold Injury or battery damage, avoid sparks near the batteries. CRANKCASE OIL HEATER The tractor is designed to permit use of a 240-watt electrical crankcase oil heater. The heater warms the oil in the crankcase to facil- itate engine starting. To install the crankcase oil heater, drain crankcase oil and remove plug (Fig. 10-10-4) from right front side of case. Apply thread paste to threads of heater, install heater and refill crankcase. When heater is to be put to use, re- SM-2075 (Jun-67) Litho in U.S.A.

John Deere 760 Tractor Service Manual

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