1966 Oliver 1550 / Cockshutt 1550 Tractor Shop Manual (P/N 432 512)

This 1966 factory shop manual (P/N 432 512), issued 8-8-66, covers Oliver 1550 and Cockshutt 1550 tractors with gasoline, LP gas, and diesel engine configurations.

PDF Reading and Wiring Detail

Search, navigation and diagrams: The manual content is not text-searchable, and the file has no embedded PDF bookmarks. The full-page tractor wiring diagrams require zooming to read small wire-color and terminal labels.

One printable English PDF contains 298 pages, including one added cover page and 297 manual pages.

Engine, Drive and Hydraulic Repair Coverage

These selected repair topics outline the manual’s coverage. Other sections include belt-pulley service and three-point-hitch leveling adjustments.

• Engine overhaul: Engine removal and installation, cylinder-head overhaul, valve-seat refacing, wet-sleeve replacement, crankshaft inspection, and oil-pump service.

• Fuel systems: Marvel-Schebler carburetor overhaul, Ensign LP gas carburetor and regulator service, and Roosa-Master injection-pump testing and timing.

• Accessory drives: Hydra-Power and Creeper Drive disassembly and assembly, plus Industrial Reverse-O-Torc pressure checks, performance testing, and reversing-gear overhaul.

• Clutch and PTO: Engine-clutch repair and adjustment, with removal, bearing service, and clutch adjustment for single- and dual-speed PTO assemblies.

• Hydraulics: Draft-control troubleshooting, servo-valve and pump repair, Hydra-Lectric circuit tests, and external hydraulic-cylinder overhaul.

• Electrical systems: Holley 1500 PT distributor service, alternator component tests, both voltage-regulator types, starting-motor repair, and serial-specific wiring diagrams.

• Steering and axles: Saginaw manual steering and Hydramotor service, Cessna power-steering pump testing, rear-axle bearing adjustment, and front-end repair.

The manual is written for qualified service personnel with access to the special tools and shop equipment required for overhaul work.

Engine Overhaul and Assembly Checks

The engine sections combine running-clearance charts and component-specific torque tables with step-by-step procedures for cylinder-head work, timing gears, pistons, connecting rods, sleeves, and crankshaft installation. These references support inspection and assembly decisions throughout an overhaul, including checks of sleeve projection, bearing clearances, and cylinder-head tightening sequences.

The Lubrication Diagram traces pressure, intermittent-pressure, and gravity-fed oil paths. Air-system coverage distinguishes oil-bath and dry-type cleaners; cooling-system procedures cover the radiator, thermostat, and water pump.

The sleeve-removal discussion warns that accumulated deposits can catch the upper sleeve bore and break the crankcase. Routine operator lubrication and maintenance are referred to the separate tractor operator’s manual.

Gasoline, LP Gas and Diesel Fuel Service

Fuel-system coverage is separated by configuration. The Carburetor Exploded View supports Marvel-Schebler disassembly and assembly, while the Ensign sections include regulator inspection, valve-lever checks, and test-stand procedures illustrated by the Regulator Diagram.

Diesel coverage includes low- and high-pressure fuel-system bleeding, injector opening-pressure and leakage tests, a nozzle troubleshooting chart, and energy-cell cleaning and service. The Fuel Injector Cutaway identifies the nozzle-holder components involved in these checks.

Roosa-Master procedures cover pump removal and installation, transfer-pump pressure, automatic advance, and dynamometer-based torque-screw checks. The manual identifies the No. 13366 timing window and No. 13369 drive-shaft seal installation tool. It warns that pinched or cut drive-shaft seals can allow fuel into the crankcase and cause serious engine damage. Injection-pump service requires trained personnel and suitable equipment.

When working on high-pressure diesel lines, LP gas components, or hydraulic circuits, observe the manual’s safety precautions.

Hydra-Power, Creeper Drive and Reverse-O-Torc

Hydra-Power coverage separates clutch-circuit testing from lubrication-circuit testing and relates symptoms such as slipping, delayed engagement, and overheating to possible causes. Internal procedures cover the hydraulic clutch, overrunning clutch, pump, valves, shafts, and bearings.

Creeper Drive instructions include shaft assemblies, bearing adjustment, and the lockout mechanism. The Straight Drive group starts with 1550 procedures but contains three later pages headed “2050–2150 Tractor Shop Manual.”

For Industrial tractors, Reverse-O-Torc coverage includes converter alignment, regulator checks, and reversing-gear repair. The torque converter is welded closed and is replaced as a unit; the reversing gear can be disassembled.

Draft Control and Hydra-Lectric Diagnosis

Hydraulic sections address the internal lift cylinder, servo valve, pump and manifold, relief valve, flow divider, and oil cooler. Design-change discussions distinguish revised linkage and valve components.

The Hydra-Lectric Control Unit and Remote Cylinder Wiring Diagram accompanies continuity, short-circuit, switch, and solenoid tests. This lets a technician compare electrical faults with hydraulic causes of poor remote-cylinder operation before selecting the repair. External-cylinder coverage distinguishes Hydra-Lectric and depth-stop assemblies.

Ignition, Charging and Steering Repair

Distributor procedures include ignition timing, contact alignment, centrifugal and vacuum advance, and overhaul supported by the Distributor Exploded View. Charging-system sections provide rotor, stator, diode, and alternator-output tests, followed by separate adjustment procedures for two-unit and single-unit regulators.

Steering coverage extends to Hydramotor troubleshooting and overhaul, steering-cylinder service, and power-steering pump pressure testing. Rear-axle and front-end sections include bearing settings, steering-knuckle work, and axle-pivot bushing replacement.

Engine Temperature and Hydra-Power Pressure Preview

Engine temperature: The basic-engine specifications list an operating-temperature range of 155–212°F for gasoline, LP gas, and diesel engines.

Separate drive circuits: At 2400 engine rpm, the Hydra-Power specification table lists clutch-circuit pressure at 140–190 psi and lubrication-circuit pressure at 20–60 psi. The service section provides separate checks for these circuits.