John Deere MODEL: 720 Series Tractor THIS IS A MANUAL PRODUCED BY JENSALES INC. WITHOUT THE AUTHORIZATION OF JOHN DEERE OR IT'S SUCCESSORS. JOHN DEERE AND IT'S SUCCESSORS ARE NOT RESPONSIBLE FOR THE QUALITY OR ACCURACY OF THIS MANUAL. TRADE MARKS AND TRADE NAMES CONTAINED AND USED HEREIN ARE THOSE OF OTHERS, AND ARE USED HERE IN A DESCRIPTIVE SENSE TO REFER TO THE PRODUCTS OF OTHERS. JD-S-SM2020
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John Deere 720 | 730 Tractor Service Manual · john deere model: 720 series tractor this is a manual produced by jensales inc. without the authorization of john deere or it's successors.
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John Deere
MODEL:
720 Series Tractor
THIS IS A MANUAL PRODUCED BY JENSALES INC. WITHOUT THE AUTHORIZATION OF JOHN DEERE OR IT'S SUCCESSORS. JOHN DEERE AND IT'S SUCCESSORS
ARE NOT RESPONSIBLE FOR THE QUALITY OR ACCURACY OF THIS MANUAL.
TRADE MARKS AND TRADE NAMES CONTAINED AND USED HEREIN ARE THOSE OF OTHERS, AND ARE USED HERE IN A DESCRIPTIVE SENSE TO REFER TO THE PRODUCTS OF OTHERS.
TO THE JOHN DEERE SERVICEMAN This Service Manual contains maintenance in
structions for the John Deere "720" Series Diesel Tractor. Included 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. Dimensions of many new wearing parts are given as an aid in determining when parts replacement is necessary. Tests and adjustments, required to keep the tractor operating efficiently, are explained in detail.
The manual also contains complete instructions for performing the predelivery, delivery, afterdelivery and ISO-hour services outlined in the Service Policy which accompanies each tractor. By using this information, you will be sure that the tractor is ready to perform efficiently and economically when it is delivered to its new owner and that it will be restored to peak efficiency when it is brought into your shop for afterdelivery services. A section on "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.
The sections in this manual concerning the power steering mechanism, fuel injection pumps and nozzles, electrical equipment and Powr-Trol
are limited mainly to removal and installation instructions. Full maintenance instructions for the power steering mechanism are given in Service Manual SM-2016, "Power Steering for John Deere Tractors." When additional information, concerning the fuel injection pumps and nozzles, is required, see Service Manual SM-2018, "Testing and Servicing Fuel Injection Pumps and Nozzles." Instructions for testing, repairing and adjusting the generator and electric cranking motor are given in Service Manual SM-2000, "Tractors and Engines (General)." For additional information concerning the Custom Powr-Trol mechanism, consult Service Manual SM-2022, "Custom PowrTrol."
This manual is written specifically for "720" Series Diesel Tractors with Serial Numbers above 7214900. However, most of the information it contains applies equally to tractors with Serial Numbers below 7214900. Where procedures are completely different, the exceptions are noted and described. When variations are minor, the serviceman will be able to apply the information without difficulty.
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.
Cutaway View 01 John Deere "120" Seriell Diellel Tractor with Galloline Cranking Engine
The John Deere "720" Series Diesel Tractor has sufficient power to pull five 14-inch plow bottoms or the equivalent under normal conditions. The tractor is available in two basic styles: general-purpose or standard. In both styles the majority of parts and components are identical. Both types have six forward speeds and one reverse.
The features of the tractor are described briefly in the paragraphs which follow. Full descriptions of each of the assemblies are given in the various sections throughout the manual.
WARNING LAMP (EXTRA)
SERIAL NUMBERS. Each tractor bears a serial number located on
the right-hand side of the main case just in front of the belt pulley.
Cranking engines on tractors with serial number 7214900 and up have a serial number located on the cylinder block at the clutch housing flange.
The cranking engine distributor, Powr-Trol valve housing, and hydraulic remote cylinder also bear serial numbers.
Figure 10-S-1-John Deere "720" SerieB General-PurpoBe DieBel Tractor-Flywheel Side
Turn engine until the valve that has been adjusted is wide open and adjust other valve. Repeat operation for remaining three cylinders.
AIR CLEANER Remove air cleaner (Figure 40-20-8) and in
spect for dirt or other foreign matter in the element. If dirt is present, work it out thoroughly with solvent or diesel fuel. Do not use a steam cleaner as this will not remove foreign matter from the center of the element.
Figure 40-20-8-Cranking Engine Air Cleaner
SM·2020 (12-57)
CARBURETOR ADJUSTMENTS THROTTLE LINKAGE.
Remove throttle rod (Figure 40-20-9) from carburetor throttle shaft lever. Hold governor arm and throttle shaft lever in the wide-open position. Turn the nuts on end of throttle rod until rod is short of going into hole in throttle shaft lever by one full turn of the nuts. Re-connect throttle rod.
A small amount of float level variation does not materially affect the operation of the engine. However, if the carburetor is removed the float level should be checked.
The correct specification is 1-3/16-inch from the machined gasket surface to the bottom of the float.
To make the check, remove carburetor bowl and measure position of float as shown in Figure 40-10-9. If float level is incorrect, adjust by bending the float hinge.
Ring side clearance: 1st (top), groove ................................................ . 2nd, 3rd, and 4th grooves ........................................ . 5th groove ...................................... , ............... , 6th groove .. , ................................................... .
PISTON PINS Diameter ........................................................ . Fit in piston ..................................................... . Fit in piston pin bushing ........................................... .
CONNECTING RODS Piston pin bushing inside diameter .................................. . Piston-pin-to-bushing clearance ..................................... . Connecting rod bearing oil clearance ................................ . Connecting rod bearing diameter .................................... . Connecting rod bore without inserts ................................. . Thickness of connecting rod inserts .................................. . Connecting rod bearing oil clearance ................................. .
CRANKSHAFT AND MAIN BEARINGS Right and left main bearing bores ................................... . Center main bearing bore .......................................... . Main bearing journals ............................................. . Right and left bearing oil clearance ................................. . Center bearing oil clearance ........................................ . Fit of main bearing housings in bores ................................ . Connecting rod journals ........................................... . Connecting rod bearing oil clearance ................................ . Pulley bearing journal ............................................. . Pulley bushing diameter (installed) .................................. . Pulley bearing oil clearance. . . ..................................... . Crankshaft end play. . . . .......................................... .
CAMSHAFT AND BEARINGS Right-hand bearing ............................................... . Right-hand bearing journal ........................................ . Center bearing ................................................... . Center bearing journal. ............................................ . Clear.ance between right-hand and center bearings and journals ......... . Left-hand bearing ................................................. . Left-hand bearing journal. ......................................... . Clearance between left-hand bearing and journal ...................... .
CAP SCREW AND STUD NUT TENSION Cylinder head nuts ................................................ . Connecting rod bolt nuts .......................................... . Cylinder-block-to-case nuts ........................................ . Center main bearing housing cap screws ............................. . Right and left main bearing cap screws .............................. . Flywheel bolt nuts ................................................ . Camshaft set screw ............................................... . SM-2020 (12-57) ®
Specifications
Dim.ension of New Part or Other Specification
0.0040 to 0.0060 in. 0.0025 to 0.0045 in. 0.0015 to 0.0035 in. 0.0010 to 0.0040 in.
2.3545 to 2.3550 in. 0.0000 to 0.0011 in. 0.0010 to 0.0025 in.
2.3560 to 2.3570 in. 0.0010 to 0.0025 in. 0.001 to 0.004 in. 3.7510 to 3.7530 in. 4.0020 to 4.0030 in. 0.1250 to 0.1255 in. 0.002 to 0.005 in.
4.5045 to 4.5055 in. 4.5006 to 4.5030 in. 4.4975 to 4.4985 in. 0.0060 to 0.0080 in. 0.0021 to 0.0055 in.
0.000 to 0.005 in. press fit 3.7480 to 3.7490 in. 0.0020 to 0.0050 in. 2.4320 to 2.4340 in.
2.4375 min. dia. after assy. 0.0030 to 0.0055 in. 0.0050 to 0.0100 in.
1.5020 to 1.5040 in. 1.4990 to 1.5000 in. 2.5005 to 2.5025 in. 2.4975 to 2.4985 in. 0.0020 to 0.0050 in. 1.4995 to 1.5005 in. 1.4960 to 1.4970 in. 0.0025 to 0.0045 in.
DESCRIPTION The shifter mechanism is composed of a gear
shift lever, quadrant, and a set of gear shifters
(Figure 130-10-1) mounted on shifter shafts, which
move the transmission gears into various combi
nations for different tractor speeds. Shifting of the
transmission drive pinion to direct drive or over
drive is accomplished by the same lever that shifts
the sliding gears.
A -Overdrive Shifter B -Fourth and Sixth Speed Shifter C -Second and Fifth Speed Shifter D -Overdrive Shifter Shaft E -Second, Fourth, Fifth, Sixth, and Reverse Speed
Shifter Shaft F -First and Third Speed Shifter Shaft G -First and Third Speed Shifter Arm H -Firat and Third Speed Shifter
Figure 130-IO-I--:Shilter Shalt. and Shilter Auernbly
Pawls, springs, and detents in the shafts and
shifters and in the main case hold the shifters and
their related gears in both neutral and engaged
positions. Pawls in second and fifth, fourth and
sixth and overdrive shifters are positively locked
in the detents on the shifter shafts when the gears
are engaged. The locks are disengaged when the
gear shifter is moved to neutral.
SM·2020 (12·57) ~ ~;~.
REMOVAL Quadrant and Transmission Cover Assembly
Disconnect wires from electric cranking motor and remove motor.
Disconnect cranking engine clutch linkage and
decompression control rod.
Figure 130-10-2-Removing Quadrant and Transmiuion Cover Auembly
Loosen the four cap screws which attach the
grille to the hood.
Remove cap screws which fasten quadrant to
steering shaft support. Raise steering shaft sup
port and rear end of hood about 2 inches.
Remove transmission case cover retaining cap
screws. With gear shift lever in neutral, remove
cover and quadrant assembly (Figure 130-10-2).
Shifters and Shafts
Remove flywheel cover, flywheel, and timing
gear housing (page 60-20-2). CAUTION: Do
not damage gasket between governor case
and timing gear housing. If the gasket is dam
aged, it will be necessary to cut a new gasket and