Ford 550/555 Tractor Backhoe Loader Service Manual (P/N 40055020)

• A 667-page PDF of Ford Tractor Operations service material for 550 models built from 1975 through March 1978 and 555 models from April 1978, covering diesel and gasoline configurations.
• Engine overhaul covers crankshaft and main bearing service, camshaft bearing replacement, timing gear installation, and cylinder bore reconditioning, along with cooling-system diagnosis and repair.
• Diesel injector testing includes nozzle opening pressure, spray pattern, seat leakage, and leak-back checks; gasoline coverage includes carburetor overhaul and governor linkage adjustment.
• 6x4 manual-reversing and 4x4 power-reversing transmissions have separate service sections, including clutch work, bearing adjustments, hydraulic pressure checks, and torque-converter stall testing.
• Rear axle procedures address planetary reduction gears, differential lock, disc brakes, and parking brakes. Steering coverage includes pump testing and steering motor overhaul.
• Loader and backhoe work extends to lift arms, boom, swing post, cylinder resealing, and standard or extendible dipstick service, plus return-to-dig and 550 Auto-Dig controls.
• Electrical troubleshooting covers starting, charging, and gasoline ignition systems, with wiring diagrams for engine, instrument-panel, and cab equipment.

Engine System and Fuel Documentation

The manual outlines procedures for cylinder head disassembly, valve train inspection, and piston ring replacement. Lubrication coverage details rotor-type oil pump function and main gallery oil flow; the Oil Pump Assembly exploded view identifies the pump’s internal components.

Cooling-system service distinguishes the water pumps used before and after March 23, 1981, engine date code 1C23. The later pump uses a stamped-steel impeller and cassette-type seal. Its internal parts are not interchangeable with those of the earlier pump. Separate radiator removal procedures address the two tractor models.

Fuel-system work includes bleeding, throttle adjustment, and optional Thermostart cold-start equipment. A Sectional View of Fuel Injection Pump supports the operating description, while the test plan for distributor pump 6233F651 specifies Hartridge 875 or 1100 test machines. Gasoline fuel delivery receives its own treatment, including the fuel pump, filter, and sediment bowl. Specification tables distinguish Holley carburetors with and without the hillside flooding kit from Facet carburetors. Dry dual-element air cleaner service is also covered.

Transmission, Axle, and Steering Repair

The power-reversing section separates earlier blocker-valve transmissions from the modulator-valve design introduced in April 1981. It explains changes to the clutches, oil distributor, converter, and cooling system, supported by a Modulator Valve (Sectional View). Converter coverage is limited to testing, cleaning, inspection, and replacement: the welded converter cannot be disassembled.

Axle work includes pinion and differential bearing preload adjustment, wheel hub service, and front axle toe-in. Front-drive coverage includes the AE3-184 axle; the transfer-gear chapter specifically identifies the 555A, rather than providing full-machine coverage for that model. The separate “Separating the Unit” part covers engine, transmission, and rear axle removal and installation.

Loader and Backhoe Hydraulics

Valve identification matters here. The manual separates 550 monoblock and sectional backhoe valves from the 555 sectional valve, with two- and four-lever control arrangements. The Model 555 Hydraulic Schematic—Four Lever Backhoe Control with Extendible Dipstick shows the circuits for that configuration.

Diagnosis goes beyond relief-pressure checks. Pump performance and suction-leak tests, circuit and accumulated-leakage “Tee” tests, and swing cushioning checks help distinguish pump, valve, and cylinder faults. Extendible dipstick repair includes internal and external wear plates.

Pump sections distinguish Cessna, Webster, and Sperry-Vickers designs, including the February 22, 1982 change to the Sperry-Vickers pump. Repair limits are explicit: the latter is serviced as an assembly, with repairs limited to its seal kit.

The repair notes warn that direct vise clamping can crush the hollow 550 swing spool. Uneven or excessive tightening of the loader-valve tie bolts can warp the valve sections and cause leakage or failure.

Electrical, Cab, and Air Conditioning

The Wiring Schematic (Less Air Conditioner) is supplemented by cab air-conditioning wiring and harness illustrations. Electrical tests cover starter current draw and voltage drop, alternator output and rectifiers, and distributor timing and advance.

Cab removal, heater core and blower service, and original R-12 air-conditioning diagnosis are included. Refrigeration coverage addresses leak testing, evacuation, charging, and performance checks; compressor repairs are limited to the clutch, pulley, coil, and shaft seal assemblies.

Specification Highlights and Shop Tooling

Reference tables provide bore and stroke dimensions, compression ratios and test data, valve and bearing clearances, wear limits, fluid capacities, and component-specific torque values. Cylinder-head tightening sequences accompany the engine procedures.

Special-tool references include the Nuday 2142 clutch fixture, 2141 differential bearing preload gauge, and 2755/2760 hydraulic testers, with the required test fittings identified.

The manual’s safety requirements address the loader lift-cylinder safety bar, support of heavy structural members, and hazards from pressurized hydraulic and refrigerant systems.