Part of the John Deere Repair Manuals.
Wrenching on a John Deere 720 diesel? This 342-page John Deere 720 Service Manual PDF (OEM #SM2020) walks you through the two-cylinder diesel, the pony cranking engine, Powr-Trol hydraulics, transmission, and final drives from teardown to reassembly. Inside: factory wiring diagrams for the generator, voltage regulator, and lighting harness, a full troubleshooting section, and page after page of tune-up and adjustment procedures for both engines. Check compression at 450 to 490 psi, set the rockshaft relief valve between 1300 and 1400 psi, and verify cranking motor brush tension at 24 to 28 ounces before you button it up. These old two-bangers don't forgive guesswork. Bookmarked by section, this PDF opens on any laptop, tablet, or phone; carry it right out to the tractor and get to work.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| Description, Operation and Specifications | 11-22 | Tractor Description (Pulls Five 14-Inch Plow Bottoms, General-Purpose and Standard Styles, Six Forward Speeds and One Reverse), Serial Number Locations for Tractor, Cranking Engine, Distributor, Powr-Trol Valve Housing and Remote Cylinder, General Specifications |
| Predelivery, Delivery, After-Delivery and 150-Hour Services | 23-48 | Dealer Service Policy Check Lists: Predelivery Inspection, Delivery Inspection and the 150-Hour Inspection, As Issued in the Booklet Accompanying Each New Tractor |
| Tune-Up and Adjustment | 49-76 | Purpose of Tune-Up and Adjustment, Diesel Engine Tune-Up, Cranking Engine Tune-Up and Clutch Adjustment |
| Diesel Engine | 77-112 | Description, Cylinder Head, Valves, And Related Parts, Pistons, Connecting Rods and Cylinder Block, Crankshaft, Flywheel |
| Cranking Engine and Accessories | 113-154 | Cranking Engine, Valve Mechanism, Governor, Camshaft, And Related Parts, Pistons and Connecting Rods, Crankshaft and Bushings, Cranking Engine Cooling System |
| Governor and Speed-Control Linkage | 155-170 | Governor Shaft Assembly, Governor Case and Fan Shaft Assembly, Fan Drive Assembly |
| Electrical System | 171-174 | Generator and Voltage Regulator, Battery, Lights, And Wiring Harness |
| Cooling System | 175-184 | Description, Radiator and Thermostat, Diesel Engine Water Pump |
| Diesel Engine Lubrication System | 185-196 | Oil Pump and Drive Assembly, Oil Filter, Pressure Regulator and Oil Lines |
| Fuel System | 197-212 | Description and Operation, Fuel Tank and Sediment Bowl, Fuel Transfer Pump, Fuel Filters, Fuel Injection Pumps, Injection Nozzles, Air Cleaner and Pipes |
| Pulley, Clutch and Pulley Brake | 213-224 | Pulley and Clutch, Pulley Brake, Clutch Parts, And Reduction Gear Cover |
| Transmission | 225-246 | Description and Operation, Shifter Mechanism, Transmission Shafts and Gears |
| Powershaft | 247-270 | Powershaft Driving and Shifting Mechanism, Powershaft Clutch, Clutch Drum and Oil Pump |
| Differential and Final Drive | 271-284 | Group 05 Differential (Spider with Three Bevel Pinions, Differential Ring Gear Driven Off the Transmission Countershaft, Differential Shaft on Tapered Roller Bearings, End Play Set by Shims), Final Drive Gears on the Rear Axles |
| Float-Ride Seat | 285-288 | Float-Ride Seat and Seat Cushions |
| Brakes | 289-292 | Brake Shoe Assembly, Brake Drum, Brake Shaft, Pedal, Cam, Adjusting Screw |
| Wheels and Tires | 293-308 | Front Wheels, Rear Wheels, Tires and Wheel Weights |
| Steering Mechanism and Front Axle | 309-332 | Steering Mechanism, Roll-O-Matic, Wide Adjustable-Tread Front Axle |
| Custom Powr-Trol | 333-342 | General Description and Pump, Remote Cylinder Valve Housings and Rockshaft Housing |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| rockshaft relief valve opening pressure | 1300 to 1400 psi | p. 40 |
| single valve housing relief valve opening pressure | 1230 to 1300 psi | p. 43 |
| Compression pressure | 450 to 490 pounds per square inch | p. 53 |
| Cranking motor Brush Tension | 24-28 oz. | p. 143 |
| AB 4744 R Starts to Open | 160° F | p. 180 |
| AB 4744 R Fully Open | 182° F | p. 180 |
| Sediment bowl service interval | 10 hours of operation | p. 203 |
| 1st Stage Filter service interval | 450 hours of operation | p. 203 |
| Air cleaner service interval | 30 hours of operation | p. 211 |
| Fuel transfer pump pressure | 12 to 24 psi | p. 201 |
| Injection nozzle opening pressure | 2400 psi | p. 209 |
| Diesel Engine Rated Load Speed | 1125 rpm | p. 12 |
