Toro Wheel Horse 520H Parts Manual

The Toro Wheel Horse 520H is a professional-grade riding lawn tractor featuring a 20HP engine, 52-inch cutting deck, hydrostatic transmission, heavy-duty frame, and versatile attachment system. This manual provides comprehensive parts identification, ordering information, assembly diagrams, maintenance specifications, and safety guidelines for proper operation and service of your 520H tractor. Below are key sections covering parts lists, diagrams, specifications, maintenance, and troubleshooting.

1. Parts Identification & Diagrams 2. Engine Components 3. Drive Train & Transmission 4. Cutting Deck & Blades 5. Electrical System 6. Controls & Operator Station 7. Hydraulic System 8. Attachments & Accessories 9. Maintenance Schedule 10. Safety Information 11. Troubleshooting & Service

Parts Identification & Diagrams

Exploded-view diagrams with corresponding part numbers for all major assemblies.

Assembly	Diagram Reference	Key Components
Main Frame	Figure 1-1	Frame rails, mounting brackets, pivot points
Engine Mounting	Figure 2-1	Isolation mounts, hardware, engine plate
Front Axle	Figure 3-1	Spindles, steering linkage, tie rods
Rear Axle	Figure 4-1	Axle housing, differential, hubs
Cutting Deck	Figure 5-1	Deck shell, spindle assemblies, belt guards
Operator Platform	Figure 6-1	Seat, fenders, floor pan, control panel

Engine Components

20HP Kohler Command Pro or Briggs & Stratton Vanguard engine parts breakdown.

Cylinder Head Assembly: Valves, springs, keepers, gaskets.
Crankcase Components: Crankshaft, connecting rods, bearings, seals.
Fuel System: Carburetor, fuel pump, lines, filters.
Ignition System: Spark plugs, ignition coils, flywheel, magnets.
Cooling System: Blower housing, cooling fins, fan.
Lubrication: Oil pump, filter, dipstick, drain plug.

WARNING! Disconnect spark plug wire before servicing engine. Allow engine to cool completely.

Drive Train & Transmission

Hydrostatic transmission and drive axle components.

Transmission Assembly: Pump, motor, charge pump, filter.
Drive Shaft: U-joints, yoke, splined couplers.
Axle & Differential: Ring & pinion, spider gears, axle shafts.
Brakes: Disc brake rotor, caliper, pads, parking brake mechanism.
Hydrostatic Linkage: Control lever, rods, neutral return spring.

CAUTION! Transmission contains high-pressure hydraulic fluid. Relieve pressure before disassembly.

Cutting Deck & Blades

Deck Shell: 52-inch fabricated steel, reinforcement ribs.
Spindle Assemblies: Triple spindle design, sealed bearings, pulleys.
Blades: High-lift mulching blades (part # 12345X), standard blades (part # 12346X).
Belt Drive: Main drive belt (part # 67890X), spindle belts (part # 67891X).
Deck Lift: Lift arms, pivot pins, hydraulic cylinder (if equipped).
Anti-scalp Rollers: Front and rear rollers, mounting brackets.

Electrical System

12-volt electrical system with alternator charging.

Key Components: Battery (12V, 300 CCA), starter motor, solenoid, ignition switch, safety interlock switches, headlights, hour meter.

Wiring Harness: Color-coded wiring diagram included. Fuses: 20A main fuse, 10A accessory fuse. Charging System: Stator, regulator/rectifier. Starting System: Starter gear, Bendix drive.

Controls & Operator Station

Steering wheel, pedals, levers, and instrument panel.

Turn off engine and remove key before adjusting controls.
Steering: Steering wheel, column, gearbox, tie rods.
Foot Controls: Brake pedal, hydrostatic speed control pedal.
Hand Controls: Deck lift lever, PTO engagement lever, throttle.
Instrument Panel: Key switch, hour meter, indicator lights.

Tip: Lubricate all control linkage pivot points annually.

Hydraulic System

Hydraulic lift system for deck and attachments (if equipped).

Hydraulic Pump: Gear pump, mounting bracket, drive coupling.
Control Valve: Spool valve, relief valve, ports.
Cylinders: Deck lift cylinder, loader/attachment cylinders.
Hoses & Fittings: High-pressure hoses, quick-connect couplings.
Reservoir & Filter: Hydraulic fluid tank, suction filter.
Fluid Specifications: Use Toro HYDO fluid or equivalent UTF.

WARNING! Hydraulic fluid under pressure can cause injury. Depressurize system before service.

Attachments & Accessories

Compatible attachments for 520H tractor.

Snow Blower (48-inch): Auger, impeller, chute rotation. Front Loader: Bucket, lift arms, hydraulic kit. Rear Bagger: Collection system, chute, bags. Aerator: Tine drum, weight kit. Dethatcher: Spring tines, depth roller.

Maintenance Schedule

Regular maintenance intervals and procedures.

Daily: Check fluid levels, tire pressure, inspect for leaks. 50 Hours: Change engine oil and filter. 100 Hours: Grease fittings, check belts, clean air filter. 200 Hours: Change hydraulic filter, check spark plugs. Seasonal: Sharpen/replace blades, check battery, store properly.

CAUTION! Always use genuine Toro replacement parts for optimal performance and warranty.

Safety Information

Safety symbols, operating precautions, and protective equipment.

Symbol	Meaning	Precaution
⚠️	Warning	Indicates a hazardous situation which could result in injury or death
⚡	Electrical Hazard	Disconnect battery before electrical service
🔥	Fire Hazard	Keep away from flammable materials, no smoking
✋	Pinch Point	Keep hands and feet away from moving parts

Always wear safety glasses, hearing protection, and sturdy footwear when operating or servicing.

Troubleshooting & Service

Symptom	Possible Cause	Corrective Action
Engine won't start	Dead battery, faulty solenoid, safety switch	Check battery voltage; test safety interlock switches; inspect starter circuit.
Loss of power	Clogged air filter, old fuel, weak spark	Replace air filter; drain old fuel; check spark plug gap and condition.
Poor cutting quality	Dull blades, worn belt, deck level	Sharpen/replace blades; adjust belt tension; level cutting deck.
Hydrostatic transmission sluggish	Low fluid, dirty filter, air in system	Check fluid level; replace filter; bleed air from system.
Electrical issues	Blown fuse, corroded connections, bad ground	Check fuses; clean battery terminals; verify chassis ground connection.

Service Support: Contact authorized Toro service dealer or call 1-800-348-2424. Online parts lookup: www.toro.com.