1939–1968 International Harvester Series A, B, C, Cub, H, M, MTA, 4, 6, W6TA & 9 Wheel Type Tractors Shop Manual (P/N 74-547)

• 88-page I&T shop manual PDF (manual identifier IH8) covering International Harvester wheel tractors in Series A, B, C, Cub, H, M/MTA, 4, 6/W6TA, and 9. Gasoline, distillate, LP-gas, and diesel configurations are distinguished.
• Table A expands the series designations into specific Farmall and International models. Coverage includes AV, BN, Super C, Cub Lo-Boy, HV, MV/MDV, O4/OS4/W4, O6/OS6/W6/WD6/ODS6, and W9/WR9/WR9S/WD9/WDR9 variants, with selected early/late build distinctions.
• Engine repair coverage runs from removal and tractor splitting through cylinder-head, valve-train, timing-gear, camshaft, piston/sleeve, crankshaft, flywheel, and oil-pump work. Carburetor, governor, cooling-system, and distributor or magneto service are also included.
• Diesel chapters provide a troubleshooting chart, filter and water-trap service, fuel-system bleeding, nozzle testing and repair, precombustion-chamber removal, and injection-pump timing. They also cover on-tractor checks, test-stand specifications, and overhaul of the pump’s primary, scavenging, plunger, distributor, camshaft, and governor units.
• Drivetrain sections address engine clutches, the Super MTA/W6TA torque amplifier, transmission shafts and shifter assemblies, bevel gears, differentials, final drives, brakes, and belt pulleys. PTO coverage includes non-continuous units and the independent PTO with reactor bands and a planetary rear unit.
• Hydraulic repair is divided among the Super MTA/W6TA lift system, H/M Lift-All, and A/C/Cub Touch-Control. Included procedures cover pressure testing, fault diagnosis, bleeding, pump service, control-valve and reservoir work, stop-clip adjustment, power cylinders, and cylinder/valve-block overhaul.

Engine, Transmission, and Drivetrain Documentation

The manual is organized by tractor series and component design rather than treating every model as mechanically identical. Table A identifies the model groups and the locations of engine and tractor serial numbers. It also separates early and late Super HV, Super MV, and Super MDV builds. Later sections add other change points, including H4 magneto timing before and after magneto serial 1353301 and different Series 9 PTO constructions for tractors 501–14400 and later production. Those distinctions matter when selecting the correct drawing, timing reference, clutch data, shaft arrangement, or bearing specification.

The engine material reaches beyond routine tune-up work. It describes engine-and-clutch removal, cylinder-head repair, valve-seat and guide service, valve rotators, timing-gear installation, camshaft removal, piston and sleeve inspection, connecting-rod and main-bearing work, rear-seal replacement, and oil-pump repair. Fuel-system coverage distinguishes Carter, Marvel-Schebler, Zenith, and International Harvester carburetors, the F8 gasoline-starting carburetor used on diesel engines, and the Ensign XG carburetor and Model W regulator used on Super M and 6 Series LP-gas tractors.

The diesel section concentrates on the later International Harvester Type A injection system. The Type B pump is treated as similar except that it has no scavenging pump; earlier American Bosch and old-style IH pump designs are not given a separate full overhaul procedure. Included work ranges from quick checks and bleeding through nozzle opening-pressure testing, pump timing, delivery and leakage tests, and component-level repair. Tool references include IH dry-sleeve puller SE 1213, precombustion-chamber puller 1 020 233 R91, OTC torque-amplifier dummy shaft ED-3259, and independent-PTO puller ED-3262.

Torque-amplifier and PTO coverage is equally specific. The manual explains coordinated engine-clutch and TA-clutch adjustment, removal of the TA clutch and carrier, overhaul of the planetary reduction and over-running clutch, and repair of the independent PTO drive, driven, extension, coupling, and rear-unit shafts. The torque-amplifier section identifies a critical reassembly risk: its planet gears are supplied as a matched set and must remain indexed to the carrier punch marks, while marked clutch-carrier and back-plate parts must retain their balance relationship. The Touch-Control chapter adds another warning—running the engine with the cylinder-and-valve unit removed while the pump remains disconnected from its oil supply can ruin the pump quickly.

Safety content is tied to the work. Tractor-splitting procedures call for secure support of both chassis sections, hydraulic chapters stress absolute cleanliness and controlled pressure testing, and the nozzle section warns that diesel injection spray can penetrate skin.

Specification Highlights

Condensed service-data tables and component chapters supply model-specific torque specifications, journal and crankpin dimensions, bearing and camshaft clearances, piston/sleeve/ring wear limits, valve and ignition settings, spring test data, fluid capacities, clutch setup data, hydraulic pressure-test values, and bevel-gear contact and backlash information. These are separated by model or build where the hardware changes; the manual does not apply one generic specification to every A-through-9 tractor.

Representative visuals include Fig. IH319, a front sectional view of the Series 9 engine; Fig. IH382, the diesel starting-system linkage; and Fig. IH427B, the exploded Super MTA/W6TA torque amplifier. Drivetrain and hydraulic examples include Fig. IH489 for the independent PTO, Fig. IH490A for hydraulic pressure testing, and Fig. IH525 for the Cub Touch-Control cylinder and valve unit. Electrical content is limited to ignition-system repair—battery distributors, J4 and H4 magnetos, timing marks, advance and lag tables, and component views. Full tractor wiring diagrams are not included.