Vehicle Segment:
Agricultural Tractor (Engine Focus)
Manual Advantage:
Offers definitive factory-level repair and maintenance information, crucial for the longevity and performance of David Brown engines.
Completeness:
Official factory documentation ensures accuracy and completeness for all repair and maintenance tasks.
Usability:
PDF format allows for targeted printing of specific sections or the entire manual, with searchable text for quick information retrieval.
Engine Mechanical:
Full overhaul, disassembly, assembly, inspection, and repair of all internal engine components (pistons, rings, connecting rods, crankshaft, camshaft, valves, timing gears).
Engine Fuel System:
Carburetor adjustment, overhaul, and troubleshooting; fuel pump operation and service; fuel filter replacement.
Engine Ignition System:
Spark plug specifications, ignition timing, coil and distributor testing.
Engine Cooling System:
Radiator, water pump, thermostat, and coolant hose service and replacement.
Engine Lubrication System:
Oil pump operation, oil filter service, oil pressure checks, and lubrication diagrams.
Engine Exhaust System:
Muffler, exhaust pipe, and manifold inspection and replacement.
Preventive Maintenance:
Recommended service intervals, oil change procedures, filter replacement, and general inspection points.
Troubleshooting:
Systematic diagnostic guides for common engine problems, including misfires, starting issues, power loss, and overheating.
Repair Procedures:
Step-by-step instructions for component removal, installation, and repair for all major engine systems.
Specifications:
Detailed torque specifications, clearances, tolerances, and measurements for engine components.
Depth:
Comprehensive, covering everything from basic fluid checks to complete engine rebuilds and advanced diagnostics.
Engine Type:
Diesel, 4-cylinder
Stroke:
110.0 mm (4.33 in)
Displacement:
3.0 Liters (182.8 cu in)
Compression Ratio:
Approx. 17.5:1 (verify with specific engine variant)
Horsepower Ad4 25:
Approx. 25 HP (at rated RPM)
Horsepower Cad4 30:
Approx. 30 HP (at rated RPM)
Injection System:
Direct Injection (typically via Lucas CAV or similar)
Governor:
Mechanical (variable speed control)
Note:
Safety ratings are typically applied to the complete tractor, not just the engine. Manual may cover safe operating procedures related to the engine.
Engine Safety:
Engine safety cut-offs, temperature monitoring (if equipped).
Engine Shielding:
Heat shields, guards for moving parts (belts, fans).
Oil Change Interval:
Typically 100-250 hours, depending on operating conditions and oil type (refer to manual for specific recommendations).
Air Filter Cleaning:
Regular inspection and cleaning/replacement based on dust levels and operating hours.
Fuel Filter Replacement:
As per manual recommendations, often tied to hours or as needed for fuel quality.
Engine Oil Type:
API CD or CE rated diesel engine oil, SAE 10W-30 or 15W-40 depending on climate (verify in manual).
Engine Oil Capacity:
Approx. 6.0 Liters (6.3 US Quarts) - including filter (verify in manual).
Coolant Type:
Ethylene Glycol based antifreeze mixture (typically 50/50 with distilled water).
Common Wear Items:
Valve seats, piston rings, injector tips, water pump seals.
Typical Failures:
Overheating due to cooling system neglect, fuel system contamination, worn injection pump timing.
Starting Problems:
Check battery, glow plugs, fuel delivery, and injection timing.
Power Loss:
Inspect air filter, fuel filters, exhaust restriction, and valve clearances.
Manufacturer:
David Brown Tractors Ltd.
Origin Country:
United Kingdom
Engine Introduction:
The AD4 engine series was a workhorse for David Brown in the mid-to-late 20th century, powering many of their popular tractor models.
Variants:
AD4-25, AD4-30, and other variations based on tuning and application.
Production Period:
Mid-1960s to late 1970s (approximate for engine variants within tractor lines)
