1981–1993 John Deere 316, 318 & 420 Lawn and Garden Tractor Service and Engine Repair Manuals (P/N TM1590, CTM2)

John Deere TM1590 (May 17, 1995) covers repair and diagnosis for 1981–1993 John Deere 316, 318, and 420 lawn and garden tractors. The file also includes CTM2 (April 19, 1990), the Onan engine component technical manual.

Search, bookmarks, and diagram detail: Service text in both manuals is searchable, but labels within wiring and hydraulic schematic images are not. Small schematic labels are best read with zoom. Section bookmarks cover both publications; the CTM2 parent bookmark and the Contents entry do not lead to their intended sections.

• Engine repair: Engine removal and installation, internal overhaul, valve and bearing inspection, carburetor service, and compression, crankcase-vacuum, and oil-pressure tests.

• Hydrostatic drive: Charge-pump and transmission overhaul, differential and rear-axle repair, drive-shaft removal, pressure and flow testing, and neutral-linkage adjustments.

• Steering and brakes: Manual steering gearbox overhaul, power-steering valve repair and leakage tests, shoe-and-drum brake adjustments, and parking-brake service.

• Hydraulic system: Single-, two-, and three-spool control-valve repair, rockshaft-cylinder leakage tests, hydraulic schematics, float operation, and system bleeding.

• Electrical diagnosis: Single- and dual-PTO wiring diagrams, starting and charging tests, ignition and seat-switch interlock diagnosis, and front PTO clutch service.

• Mowers and front axle: Mower gear-case rebuilds, blade-spindle and jack-sheave service, axle-pivot and spindle-bushing replacement, wheel-bearing inspection, and toe-in adjustment.

Both publications were written for experienced service technicians and identify the special tools required for the work.

Onan Engine Applications and Overhaul

The engine application chart identifies B43E or P218G engines for the 316, B43G or P218G for the 318, and B48G or P220G for the 420. Tractor-level diagnosis and engine removal are paired with the included component manual's bench repair procedures.

Internal repair covers cylinder heads, valve seats and guides, tappets, camshafts, pistons, connecting rods, and crankshaft main bearings. Inspection limits and clearance checks accompany disassembly and reassembly instructions.

The crankshaft section warns that drawing the bearing plate inward with its screws can damage the lock pins, thrust washer, or crankshaft.

Fuel and lubrication sections add governor overhaul, carburetor cleaning and float adjustment, oil-pump service, and oil-pressure regulating-valve inspection.

Hydrostatic Transmission and Differential Repair

Pump, motor, and swashplate repair is supported by charge-pressure, implement-relief, and charge-pump flow tests. Troubleshooting addresses loss of drive, creeping in neutral, overheating, and recurring charge-pump seal failures.

Four transmission-control linkage versions receive separate coverage. Differential instructions distinguish early flat thrust washers from later tabbed washers and explain the revised frame support associated with differential-gasket leaks.

Steering, Brakes, and Hydraulic Variants

The 316 steering gearbox section covers worm-bearing and over-center preload. Power-steering repair distinguishes four-port and five-port valves and includes fabrication details for the DFMX1 Steering Valve Fixture and DFMX2 Alignment Shims.

Separate steering-system and steering-valve leakage tests help distinguish a leaking cylinder from a valve fault before parts are replaced. The steering cylinder is serviced as a complete assembly.

Hydraulic control-valve instructions distinguish five two-spool versions and four three-spool versions. The Early 318 and Later 420 Hydraulic System Schematics show the different oil routing used with four-port and five-port steering.

Brake repair also covers model-specific pedal and neutral-return linkages, with checks for service, parking, and individual turning brakes.

Electrical Circuits and PTO Service

The Single PTO Electrical Schematic, Dual PTO Electrical Schematic, and Electrical Component Location views connect wiring references with component tests. Ignition diagnosis separates breaker-point systems through S.N. 420000 from electronic ignition at S.N. 420001 and above.

The engine manual adds Bendix-drive and solenoid-drive starter overhaul, stator and rectifier-regulator replacement, and ignition-module service. Front PTO clutch procedures cover teardown, field-coil checks, and armature-clearance adjustment.

Mower Gear Cases and Service References

Gear-case rebuilds cover the 50-inch mower, early 60-inch Curtis, later 60-inch Peerless, and 260 Rotary Mower. Spindle and jack-sheave sections identify the applicable early and later deck arrangements.

The 50-inch gear-case instructions address crush-ring replacement and warn that overtightening the input-shaft locknut can damage the bearing cone.

Metric-series, inch-series, and set-screw torque charts accompany component torque specifications, fluid capacities, pressure-test data, electrical test values, and wear limits.

Some tractor versions may not be covered by this edition; match the documented configuration and serial breaks to your machine. Working on pressurized hydraulics and heavy tractor powertrains carries inherent physical risks. Follow the manual's precautions for hydraulic pressure and supporting raised machinery.

Combined PDF and Page Breakdown

One printable, English-language PDF contains both publications. The 665-page PDF comprises 440 pages of TM1590, 224 pages of CTM2, and one additional introductory page. Covers, blank pages, and 14 repeated schematic pages within TM1590 are already included in these totals.