The Allis-Chalmers D-21 Series II is a powerful tractor designed for demanding agricultural applications. Produced from approximately 1963 to 1969, this model was the flagship of the D-Series line, succeeding earlier tractors with increased power and advanced features for its era. It is known for its robust construction, featuring an Allis-Chalmers 3500 Mark II 301 cubic inch inline 6-cylinder diesel engine producing approximately 103 gross horsepower. Notable technological advancements for its time include a 4-speed forward and 4-speed reverse power shift transmission, which allowed for shifting without using the clutch, and a responsive hydraulic system suitable for heavy draft operations. The D-21 Series II competed with other major manufacturers' high-horsepower offerings and was a testament to Allis-Chalmers' reputation for innovation and durability in the agricultural machinery market. This Workshop Service Manual (WSM) provides comprehensive service, repair, and maintenance information for the Allis-Chalmers D-21 Series II Tractor. It covers all major systems, including detailed engine overhaul procedures, diagnostics, and component repair for the Allis-Chalmers 3500 Mark II diesel engine. The manual also details the service and repair of the power shift transmission, final drives, hydraulic pump, control valve, cylinders, and the complete electrical system, including wiring diagrams. Owners, mechanics, and technicians will find step-by-step disassembly and assembly instructions, troubleshooting guides for common issues, tune-up specifications, lubrication charts, and information on specialized tools required for effective maintenance and repair, ensuring the longevity and optimal performance of this vintage tractor. 🏷️ Basic Information Identification Make: Allis-Chalmers Model: D-21 Series II Product Type: Service Repair Manual (WSM) Vehicle Type: Tractor 👋 Introduction Market Position Historical Context: The Allis-Chalmers D-21 was a powerful, high-horsepower tractor designed for heavy-duty agricultural work, competing in a market segment dominated by larger articulated tractors and robust conventional models. Competitive Analysis Key Competitors: During its production era, the D-21 Series II would have competed with models from John Deere (e.g., 4020, 4320), International Harvester (e.g., 806, 1206), and Case (e.g., 930, 1030). Key Features Tractor Features: Known for its robust construction, powerful engine, and advanced (for its time) power shift transmission, making it suitable for plowing, cultivation, and heavy draft operations. Manual Value Proposition Manual Benefit: This WSM is essential for owners and mechanics to maintain, diagnose, and repair the D-21 Series II effectively, ensuring longevity and optimal performance of a valuable vintage tractor. 📋 Manual Details Coverage Areas Primary Coverage: Comprehensive service, repair, and maintenance for the Allis-Chalmers D-21 Series II Tractor Engine Coverage: Detailed engine overhaul, diagnostics, and component repair Transmission Coverage: Service and repair of power shift transmission and final drives Hydraulic System Coverage: Repair and maintenance of the hydraulic pump, control valve, and cylinders Electrical System Coverage: Wiring diagrams, component testing, and troubleshooting for the electrical system Page Count Estimated Page Count: Varies by specific manual edition, typically 300-500 pages for a full WSM Manual Type Manual Type: Workshop Service Manual (WSM) / Service Repair Manual Language Language: English Format Format: Print 📖 Manual Coverage Systems Covered Engine Systems: Engine overhaul, cooling system, lubrication system, fuel system, ignition/starting system (if applicable for diesel ignition), exhaust system Drivetrain Systems: Clutch, power shift transmission, PTO (Power Take-Off) system, differential, final drives, axle assemblies Hydraulic Systems: Hydraulic pump, control valve, cylinders (3-point hitch, external hydraulics), hydraulic fluid reservoir and filters, power steering system Electrical Systems: Starter, alternator/generator, battery, lighting system, instrumentation, wiring diagrams Braking Systems: Service brakes (internal expanding shoe type), parking brake, brake pedal and linkages Steering Systems: Mechanical steering, hydraulic power steering components Chassis And Body: Frame, fenders, operator's platform, drawbar, hitches Procedures Included Maintenance Procedures: Lubrication charts, fluid change intervals, filter replacement, greasing points, pre-operation checks Repair Procedures: Step-by-step disassembly, assembly, inspection, and repair of all major components Troubleshooting Guides: Systematic diagnostic procedures for common issues and fault finding Tune Up Procedures: Engine tune-up specifications and adjustments Special Tool Requirements: Identification and usage of specialized tools required for repairs Technical Depth Depth Of Coverage: In-depth, professional-level repair and overhaul procedures, suitable for mechanics and experienced owners 📊 Manual Specifications File Format Digital Format: N/A (Print Format) Print Quality Print Quality: Professional quality printing, clear text and diagrams Binding Type Binding: Likely comb-bound or perfect-bound for durability in a workshop environment Paper Type Paper Quality: Durable, possibly coated paper to resist grease and oil ⚙️ Engine Specifications Primary Engine Engine Make: Allis-Chalmers Engine Model: Allis-Chalmers 3500 Mark II Engine Type: Diesel Displacement: 301 cubic inches (4.93 Liters) Configuration: Inline 6-cylinder Performance Gross Horsepower: Approximately 103 HP (76.8 kW) at rated governed speed Drawbar Horsepower: Approximately 85 HP (63.4 kW) Torque: Not explicitly stated in common literature, but substantial for its class. Fuel System Fuel Type: Diesel Fuel Injection System: Roosa-Master rotary injection pump (typical for this era) Fuel Filter Part Number: Refer to manual for specific AC or aftermarket equivalents (e.g., Wix 33323, Baldwin BF7736 may be...