John Deere 650 & 750 Tractor Technical Manual – 1981 (P/N TM1242)

John Deere Technical Manual TM1242 (01SEP84) combines repair procedures with separate system-operation and diagnostic sections for 650 and 750 tractors, including MFWD and non-MFWD configurations.

Printable PDF, Section Bookmarks, and Wiring Detail

Search, navigation, and diagrams: The workshop text does not support PDF text search. Seventeen embedded bookmarks link to the contents and main sections; small wire-color labels in the fold-out wiring diagram are readable when enlarged.

One printable 798-page PDF in English. The total includes the original cover, two preliminary pages, and a separator page.

Engine Overhaul, Tractor Splits, and System Diagnosis

The following is a selection of the covered work, rather than a complete contents list. Other topics include fuel-tank leak testing and hand- and foot-throttle linkage service.

• Engine repair: Valve train, cylinder head, camshaft, pistons, rods, cylinder block, crankshaft, and main bearings, with lubrication-system inspection and cooling-system repair.

• Diesel fuel system: Injection-pump removal and timing, fuel-system bleeding, injection-nozzle testing and reconditioning, governor repair, precombustion-chamber service, and Thermo-Start diagnosis.

• Power train: Step-by-step tractor separation, clutch and sliding-gear transmission repair, rear PTO, differential, final drive, MFWD assemblies, and optional front PTO service.

• Steering and brakes: Manual steering gear, field-option power-steering valve and cylinder repair, brake assembly inspection, and pedal-linkage adjustment.

• Hydraulics: Pump seal and packing replacement, rockshaft and 3-point hitch service, main and surge relief valves, selective control valve repair, and hydraulic testing.

• Electrical repair and diagnosis: Alternator and starter-motor repair, charging-system tests, wiring diagrams, and front PTO interlock fault tracing.

• Axles and operator station: Standard and MFWD front axles, wheel bearings, ROLL-GARD protective equipment, and seat-belt installation.

Suited to mechanics familiar with tractor teardown and electrical testing, with access to proper lifting equipment and hydraulic test instruments.

650 and 750 Power Train Differences

The 650 chapters address the change-shift lever, reverse-gear shaft, differential-drive shaft, and MFWD outer-drive assemblies. The 750 procedures distinguish front and rear differential-drive shaft halves, the Hi-Lo shifter, drop housing, and spindle housings, with their bearing-clearance, drag-torque, and backlash checks.

These distinctions help match the teardown procedure, inspection points, and specification tables to the tractor being serviced. Clutch, transmission, and PTO power-flow diagrams accompany troubleshooting for drive faults, noise, and oil leakage; exploded MFWD views support component identification during teardown.

Engine, Fuel, and Routine Service

Cylinder-head tightening patterns and valve-setting sequences are shown separately for each engine. Internal inspection covers piston and bearing measurements, camshaft wear, and oil-pump clearances; cooling-system work includes radiator service, water-pump rebuilding, and thermostat checks.

Nozzle procedures address opening pressure, leakage, chatter, and spray pattern. Injection-pump coverage is limited to removal, installation, and timing: the manual directs pump replacement rather than internal disassembly or repair.

Predelivery and after-sale inspections accompany tune-up, fan-belt adjustment, lubrication charts, oil and filter service, transmission-hydraulic screen cleaning, MFWD axle-oil changes, and front PTO bearing lubrication. Tables specify approved lubricants, fluid capacities, and service intervals.

Tests, Wiring, and Hydraulic Fault Isolation

Engine diagnosis includes dynamometer, compression, oil-pressure, and cooling-system tests. Engine lubrication and coolant-flow diagrams explain the circuits behind those checks.

The seven-step probe-light chart distinguishes open circuits, poor grounds, high resistance, and faulty components. Further checks cover regulator continuity, temperature and oil-pressure senders, lamps, switches, and fuses.

Hydraulic charts combine preliminary checks, oil-temperature preparation, flow-meter hookups, and pressure results to isolate pump, relief-valve, rockshaft, steering, or selective-control-valve faults. Open-center schematics distinguish standard rockshaft circuits from optional steering and SCV plumbing.

Hydraulic-pump repair covers external leaks through seal and packing replacement. Pumps with inadequate output or scored internal parts are replaced.

Component torque tables, wear limits, clearances, and electrical test specifications accompany the procedures. The tractor uses metric hardware, and most specifications include U.S. equivalents.

Separation Tools and Repair Cautions

Separation photos show blocking, support stands, and lifting arrangements for front-end, engine, clutch-housing, transmission, differential, and axle removal. Tool references identify the JDF-14 timing fixture, JDST-28 belt tension tool, JDG-19 lift eyes, and hydraulic flow and pressure testers.

Dimensioned drawings for separate 650 and 750 transmission disassembly stands support fabrication of the fixtures used to hold the transmission and differential during repair.

MFWD separation notes flag a drive shaft that can pull free of its splined coupler; engine-removal notes address oil-pan damage from supporting the engine under the pan's center. Cylinder-head warnings distinguish the smaller auxiliary screws from the main fasteners to prevent overtightening.

Tractor splitting and hydraulic pressure testing require the manual's blocking, lifting, battery-isolation, pressure-release, and leak-check precautions. This is a technical repair publication, rather than an operator's manual or parts catalog.

Examples of Crankshaft Limits and Clutch Settings

For both engines, the crankshaft inspection section specifies new-part end play of 0.09–0.19 mm, with 0.33 mm as the maximum allowable value.

The predelivery specifications list clutch-pedal free travel of 16 mm (5/8 in.) for the 650 and 22 mm (7/8 in.) for the 750.