Need the factory breakdown for your tractor? This 122-page International Harvester 544, 656, 666, 686, Hydro 70, Hydro 86 Shop Manual PDF gives you the complete teardown and rebuild procedures to get these classic machines back in the dirt. Inside, you get detailed hydraulic schematics, full wiring diagrams covering both diesel and LP gas models, and dedicated troubleshooting sections for the hydrostatic drive. Open up to step-by-step instructions for the direction reverser, power steering cylinder, and engine clutch linkage. Verify your charge pump pushes an 80 psi minimum at 700 rpm, and secure the Thompson draft hydraulic pump cap screws to exactly 25-35 ft.-lbs. Guessing at clearances costs you time and parts. Download this bookmarked file, jump straight to the spec you need, and start wrenching.
What's Inside This International Harvester 544 / 656 / 666 / 686 / Hydro 70 / Hydro 86 Manual
| System | Pages | Key Topics |
|---|---|---|
| Belt Pulley | Input Shaft, Bearing Assembly, Pulley Shaft, Driven Gear, Shims, Bevel Gears | |
| Brakes | Adjustment, Overhaul | |
| Carburetor | Gasoline, Lp Gas | |
| Clutch | Engine, Torque Amplifier, Engine Clutch Linkage, Release Levers, Release Bearing, Cam Lever | |
| Cooling System | Fan, Radiator, Water Pump, Coolant Filter, Conditioner, Bearing Assembly | |
| Diesel Fuel System | Filters, Bleeding, Injection Pump, Injection Nozzles, Precombustion Chambers, Glow Plugs | |
| Differential | Carrier Bearing Adjustment, Backlash Adjustment, Mesh Position Adjustment, Bevel Gears, Bull Pinion, Carrier Bearing | |
| Direction Reverser | R&R and Overhaul, Direction Reversing Mechanism, Clutch Housing, Transmission Drive Shaft, Planet Carrier, Reverse Sun Gear | |
| Electrical System | Alternator, Regulator, Generator, Starting Motor, Standard Ignition, Magnetic Pulse Ignition | |
| Engine | Balancer, Cam Followers, Camshaft, Connecting Rods and Bearings, Crankshaft, Cylinder Head | |
| Final Drive | Bull Gears, Bull Pinions, Wheel Axle Shaft | |
| Front System | Axle Main Member, Steering Knuckles, Tie Rods, Tricycle Type | |
| Governor | Synchronizing Governor and Carburetor, High Idle Speed, Low Idle Speed, Overhaul | |
| Hydraulic System | Auxiliary Valves, Auxiliary System Pump, Cylinder and Valve Unit, Lift Unit Pump, Test and Adjust, Trouble Shooting | |
| Hydrostatic Drive | Adjustments, Lubrication and Filter, Pressure Checks, R&R and Overhaul, Trouble Shooting | |
| Lp Gas System | Adjustments, Carburetor Overhaul, LP-Gas Filter | |
| Power Steering System | Cylinder, Flow Divider, Hand Pump, Lubrication and Bleeding, Oil Cooler, Operational Tests | |
| PTO | Pressure Check, Adjustment, Removal and Reinstallation, Overhaul | |
| Service Data | General, Tune-Up, Sizes-Capacities-Clearances | |
| Torque Amplifier | Linkage Adjustment, Overhaul T.A. Clutch, R&R and Overhaul T.A., Planet Gears, Sun Gears, Over-Running Clutch | |
| Transmission, Range | Shifter Rail, Fork, Transmission Driving Shaft, Mainshaft Pilot Bearing, Mainshaft, Countershaft | |
| Transmission | Shifter Rails, Forks, Transmission Driving Shaft, Mainshaft Pilot Bearing, Mainshaft, Countershaft | |
| F-656 | w/Alternator (Diesel), w/Generator (Diesel), w/Generator (Gas & Lpg), w/Alternator (Gas & Lpg) | |
| I-656 | Alternator, Key Switch, Glow Plug Switch, Fuel Gauge Sending Unit, Voltage Regulator, Cranking Motor | |
| 666 & 70 | Alternator, Key Switch, Oil Temp Light, Air Cleaner Indicator, Ether Push-Button |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Hand Controlled Models | ||
| Movable pump variable orifice adjustment (affects servo pressure) | loosen the orifice block by turning the adjusting bolt as required until 1/3 to 1/2 of the orifice opening is visible behind the cam. Tighten the orifice block bolts. | p. 81 |
| All Models | ||
| Charge pump pressure (at 700 rpm or higher, neutral) | 80 psi minimum | p. 83 |
| Hy-Tran transmission fluid replacement interval | every 1000 hours, or once a year, whichever occurs first | p. 10 |
| Drive control valve O-ring #2 replacement | use new | p. 94 |
| Drive control valve stem pin fit | loose, but matched fit | p. 94 |
| Hydraulic lift system relief valve opening pressure | 1800 psi | p. 104 |
| Models equipped with Cessna pump (12 GPM or 17 GPM) | ||
| Draft hydraulic pump (Cessna) assembly cap screws torque | 40 ft.-lbs. | p. 13 |
| Models equipped with Thompson pump (12 GPM or 17 GPM) | ||
| Draft hydraulic pump (Thompson) assembly cap screws torque | 25-35 ft.-lbs. | p. 13 |
| 544 Non-Diesel, 544 Diesel | ||
| Number of Cylinders (544 Non-Diesel, 544 Diesel) | 4 | p. 4 |
| 656 Non-Diesel, 656 Diesel, 666, 686, Hydro 70, Hydro 86 | ||
| Number of Cylinders (656 Non-Diesel, 656 Diesel, 666, 686, Hydro 70, Hydro 86) | 6 | p. 4 |
| 544 Diesel, 666, Early 686 Diesel, Hydro 70, Early Hydro 86 Diesel, Late 686, Hydro 86 Diesel | ||
| Engine Low Idle rpm (Diesel) | 700 rpm | p. 6 |
| 544 Non-Diesel | ||
| Cooling System Capacity | 14 quarts | p. 5 |
