John Deere 3520 Manual: A Comprehensive Guide

General Information

Safety Precautions

Operating any piece of heavy machinery, including your John Deere 3520 tractor, requires a strong commitment to safety. Always familiarize yourself with the location and function of all safety devices, such as ROPS (Rollover Protection Structure) seatbelts, and warning labels. Before starting the engine, thoroughly inspect the area around the tractor to ensure no bystanders, pets, or obstacles are present. Never operate the tractor under the influence of alcohol, drugs, or any medication that impairs your judgment or reaction time. Taking a moment to review the safety guidelines before each use can significantly reduce the risk of accidents and injuries.

Furthermore, it's crucial to maintain a safe operating environment by keeping the tractor clean and free of debris. Be especially cautious when working on slopes or uneven terrain, as these conditions can increase the risk of rollovers. Always engage the parking brake and lower all implements to the ground before dismounting the tractor. Never allow passengers to ride on the tractor unless it is equipped with a designated passenger seat. Remember, prioritizing safety is paramount to ensuring a long and productive life with your John Deere 3520.

Serial Number Locations

Locating the serial numbers on your John Deere 3520 is essential for ordering parts, registering the tractor, and accurately identifying its model year. The main tractor serial number is typically stamped on a metal plate located on the frame, often near the front axle or dashboard. In addition to the main tractor serial number, individual components such as the engine and transmission may also have their own serial numbers. These numbers are crucial for identifying specific parts and ensuring compatibility when ordering replacements.

Take the time to record all serial numbers and store them in a safe place, such as in a maintenance log or on your computer. Having these numbers readily available will save you valuable time and effort when you need to order parts or seek technical assistance. If you are unsure of the exact location of the serial numbers, consult the parts catalog for a detailed diagram. Always double-check the numbers to ensure accuracy, as even a slight discrepancy can lead to ordering the wrong parts.

Tractor Specifications

Understanding the specifications of your John Deere 3520 is vital for performing proper maintenance, troubleshooting issues, and selecting the correct implements. This tractor boasts a reliable diesel engine, providing ample power for a variety of tasks. Key specifications include engine horsepower, hydraulic flow rate, PTO (Power Take-Off) horsepower, and fuel tank capacity. Knowing these figures allows you to optimize performance and avoid overloading the tractor, which can lead to premature wear and damage.

The operating weight of the tractor, along with its dimensions, are also important factors to consider, especially when transporting it or working in confined spaces. Refer to the detailed specifications chart in this manual for a complete list of all relevant measurements and capacities. Pay close attention to the recommended tire sizes and inflation pressures, as these can significantly impact traction, stability, and fuel efficiency. Keeping a copy of the specifications readily available will prove invaluable when making informed decisions about your tractor's operation and maintenance.

Component Identification

Familiarizing yourself with the major components of your John Deere 3520 is fundamental to performing basic maintenance and troubleshooting minor issues. Key components include the engine, transmission, hydraulic system, electrical system, and cooling system. Each of these systems plays a critical role in the overall operation of the tractor, and understanding their functions is essential. The engine provides the power to drive the tractor, while the transmission transfers that power to the wheels.

The hydraulic system powers implements such as loaders and mowers, while the electrical system provides power for starting, lighting, and other accessories. The cooling system regulates the engine temperature to prevent overheating. Take some time to visually inspect each component and understand its location and function. By developing a basic understanding of these systems, you will be better equipped to identify potential problems early and perform routine maintenance tasks effectively. Consult the detailed diagrams and illustrations in this manual for a comprehensive guide to component identification.

John Deere 3520 Manual: A Comprehensive Guide

Operating Instructions

Pre-Start Checks

Before you even think about turning the key on your John Deere 3520, a thorough pre-start check is absolutely crucial. This isn't just a formality; it's an investment in the longevity and reliability of your machine. Start by inspecting the engine oil level using the dipstick. Ensure the level falls within the recommended range; low oil levels can lead to catastrophic engine damage, while overfilling can cause foaming and reduced lubrication. Next, check the coolant level in the radiator, making sure it's visible and at the proper mark, and examine all hoses for signs of leaks or cracks. A visual inspection of the tires is also necessary, looking for proper inflation, cuts, and wear patterns, confirming that all lights are functioning correctly, and inspecting the overall condition of belts and fluids.

Continuing the pre-start routine, pay close attention to the condition of the air filter. A dirty or clogged air filter restricts airflow to the engine, leading to reduced power, increased fuel consumption, and ultimately, premature engine wear. Clean or replace the air filter as needed, following the manufacturer's recommendations. Furthermore, inspect the fuel system for any leaks or signs of damage. Ensure the fuel tank is adequately filled with the correct type of fuel, and check the fuel lines and connections for tightness. Don't forget to inspect the hydraulic fluid level and condition, making sure the fluid is clean and at the proper level for optimal operation of all hydraulic implements. Taking the time to perform these checks thoroughly will not only prevent costly repairs but also ensure your safety and the optimal performance of your tractor.

Starting and Stopping the Engine

Starting the John Deere 3520 is a straightforward process, but proper technique is essential for engine longevity and ease of operation. Begin by ensuring the transmission is in neutral or park, depending on the transmission type of your specific model. Engage the parking brake firmly before proceeding. Next, turn the ignition key to the "on" position and wait for the glow plug indicator light to illuminate, which preheats the cylinders for easier starting, especially in cold weather. Once the glow plug light goes out, turn the key to the "start" position and hold it there until the engine starts. Avoid excessive cranking, as this can strain the starter motor and drain the battery; if the engine doesn't start after a few seconds, release the key, wait a moment, and try again.

When stopping the engine, avoid abruptly shutting it off under load, especially after heavy use. Instead, allow the engine to idle for a few minutes to allow it to cool down gradually. This prevents thermal shock and prolongs the life of the engine components. After a brief cooldown period, turn the ignition key to the "off" position. Always ensure the tractor is parked on a level surface and the parking brake is fully engaged. If storing the tractor for an extended period, consider disconnecting the battery to prevent battery drain, and taking extra precautions for fuel and coolant storage and stability.

Operating Controls

Understanding the operating controls of your John Deere 3520 is paramount to safe and efficient operation. The steering wheel controls the direction of the tractor, allowing for precise maneuvering. Pay close attention to the sensitivity of the steering system and adjust your movements accordingly. The throttle controls the engine speed, with higher throttle settings delivering more power. Use the throttle judiciously, balancing power needs with fuel efficiency and noise levels. The transmission controls the tractor's speed and direction, whether it's a hydrostatic or gear-driven transmission. Familiarize yourself with the gear ranges and shifting patterns to optimize performance for different tasks.

The hydraulic controls operate the implements attached to the tractor, allowing you to raise, lower, and manipulate them as needed. Each hydraulic lever corresponds to a specific function, such as lifting a loader, adjusting a blade, or activating a mower. Practice using the hydraulic controls to develop a feel for their sensitivity and responsiveness, allowing for smooth and controlled implement operation. The PTO (Power Take-Off) engagement lever activates the PTO shaft, which powers implements like mowers, tillers, and balers. Engage the PTO only when the engine is running at the correct speed and the implement is properly attached. Always ensure the area around the PTO is clear of obstacles and personnel before engaging the PTO.

Using Implements

The John Deere 3520 is designed to work with a wide variety of implements, significantly expanding its versatility. Before attaching any implement, carefully consult the implement's operating manual and ensure it's compatible with the tractor's specifications, regarding power, weight, and hitch type. Proper attachment is crucial for safety and performance. Connect the implement securely to the tractor's hitch, ensuring all pins and fasteners are properly secured. Check that the implement is level and aligned correctly to prevent uneven operation and potential damage.

When operating an implement, start slowly and cautiously to get a feel for its performance and handling. Adjust the implement's settings, such as cutting height or tillage depth, as needed to achieve the desired results. Be aware of the implement's weight and dimensions, especially when operating on uneven terrain or near obstacles. Regularly inspect the implement for any signs of damage or wear, and perform any necessary maintenance, such as lubricating moving parts or sharpening blades. A properly maintained implement will not only perform better but also last longer, saving you time and money in the long run.

Driving Techniques

Mastering effective driving techniques is critical for safe and efficient tractor operation. Always wear a seatbelt when operating the tractor, even for short distances. Start and stop smoothly to prevent jolting and potential loss of control. When turning, reduce your speed and avoid sharp turns, especially on slopes or soft ground. Be aware of the tractor's turning radius and avoid hitting obstacles or tipping over.

When driving on uneven terrain, adjust your speed accordingly and be prepared to counter-steer to maintain stability. Avoid driving across steep slopes, as this can increase the risk of tipping over. When driving on roads, obey all traffic laws and use caution, as tractors are slower and less maneuverable than other vehicles. Use appropriate lighting and signaling to alert other drivers to your presence. Regularly inspect the tires for proper inflation and wear, as this can significantly affect handling and stability.

PTO Operation

The Power Take-Off (PTO) is a critical component that allows the John Deere 3520 to power a wide array of implements. Before engaging the PTO, ensure that the implement is correctly attached and properly aligned with the PTO shaft. Make sure the PTO shield is in place and undamaged. This shield is a critical safety feature to prevent entanglement and serious injury. Clear the area around the implement of any obstructions or personnel.

Engage the PTO slowly and gradually, allowing the implement to reach its operating speed smoothly. Avoid engaging the PTO at high engine speeds, as this can put excessive stress on the PTO system and the implement. Monitor the implement's performance and adjust the engine speed as needed to maintain optimal operation. When disengaging the PTO, reduce the engine speed first and then disengage the PTO lever. Never attempt to repair or maintain the PTO while it is engaged or the engine is running.

Hydraulic System Operation

The hydraulic system is essential for operating many implements on the John Deere 3520. Understanding its proper operation ensures efficient and reliable performance. Before operating any hydraulic implement, check the hydraulic fluid level and condition. Ensure the fluid is clean and free of contaminants, and that the level is within the recommended range. Inspect all hydraulic hoses and connections for leaks or damage. Address any leaks promptly to prevent fluid loss and potential system damage.

When operating hydraulic implements, use smooth and controlled movements to avoid jerky operation and potential damage. Be aware of the implement's weight and hydraulic capacity. Avoid exceeding the tractor's hydraulic lifting capacity, as this can damage the hydraulic system and create a safety hazard. Regularly inspect the hydraulic cylinders and valves for leaks or damage. Perform any necessary maintenance, such as lubricating the cylinder rods and cleaning the valves. A well-maintained hydraulic system will provide reliable performance and extend the life of your implements.

Maintenance

Service Intervals

Adhering to the recommended service intervals is crucial for the longevity and optimal performance of your John Deere 3520 tractor. Regular maintenance, as outlined in this manual, will help prevent costly repairs down the line and ensure your tractor is always ready to tackle the tasks at hand. Neglecting scheduled service can lead to decreased efficiency, increased fuel consumption, and potential damage to critical components. Consult the service interval chart frequently and keep detailed records of all maintenance performed, including dates, specific tasks completed, and any parts replaced. Remember that severe operating conditions, such as heavy dust or continuous high-load work, may necessitate more frequent servicing than the standard intervals.

Proper documentation of maintenance activities is not just about keeping track; it also plays a vital role in maintaining your tractor's warranty. Accurate records serve as proof that you've followed the manufacturer's recommendations for upkeep, protecting your investment. This also comes in handy when selling the tractor. It is important to use the proper John Deere fluids. In addition, it is good to consult with an experienced John Deere maintenance tech. This is so you follow correct procedures to not damage any equipment when you are performing maintenance.

Lubrication

Proper lubrication is the lifeblood of any mechanical system, and your John Deere 3520 is no exception. Regularly lubricating the various grease fittings and moving parts reduces friction, minimizes wear, and prevents premature failure. Use only high-quality grease that meets John Deere's specifications, as inferior lubricants can break down quickly and fail to provide adequate protection. Refer to the lubrication chart for specific points and the recommended grease type for each location. Remember to wipe grease fittings clean before and after applying grease to prevent contamination from dirt and debris.

Pay close attention to areas that experience high stress or movement, such as the loader linkage, steering components, and PTO shaft. These areas require more frequent lubrication than others. Be mindful of over-greasing, as this can attract dirt and grit, creating a grinding paste that accelerates wear. A thin layer of grease is often sufficient to provide adequate lubrication. In some instances, using a spray on lubricant is the better option for chains, springs and tight areas that need maintenance.

Fluid Level Checks

Maintaining proper fluid levels is essential for the efficient operation of your John Deere 3520. Regularly check the engine oil, coolant, hydraulic fluid, and transmission fluid levels and top them off as needed. Low fluid levels can lead to overheating, reduced performance, and potential damage to critical components. Always use the correct type of fluid specified for each system, as mixing fluids can cause compatibility issues and harm your tractor.

When checking fluid levels, ensure the tractor is parked on level ground to obtain accurate readings. Allow the engine to cool down before checking the coolant level to prevent burns. Visually inspect all fluid reservoirs for leaks or signs of contamination, such as discoloration or sediment. If you notice any leaks or contamination, address the issue promptly to prevent further damage. When you refill the fluid, be sure to check the level again to ensure that you did not put too much or too little fluid in to the machine.

Filter Replacements (Oil, Fuel, Air, Hydraulic)

Filters are the silent guardians of your John Deere 3520, protecting critical components from harmful contaminants. Regularly replacing the oil filter, fuel filter, air filter, and hydraulic filter is crucial for maintaining optimal performance and preventing premature wear. Clogged or dirty filters restrict flow, reduce efficiency, and can cause serious damage to the engine, fuel system, and hydraulic system. Use only genuine John Deere filters or filters that meet the manufacturer's specifications to ensure proper filtration and protection.

Follow the recommended replacement intervals for each filter, but consider more frequent replacements if you operate in dusty or harsh conditions. When replacing filters, always clean the surrounding area to prevent dirt and debris from entering the system. Properly dispose of used filters according to local regulations. Remember to prime the fuel filter after replacement to ensure proper fuel flow to the engine. In addition, write down the last date you changed the filter, this way you have record of the last time it was replaced.

Tire Maintenance

Proper tire maintenance is essential for safe operation, optimal traction, and extended tire life. Regularly check tire pressure and maintain it at the recommended levels for the specific application. Underinflated tires can lead to increased wear, reduced fuel efficiency, and poor handling. Overinflated tires can result in a harsh ride and reduced traction. Visually inspect tires for cuts, bulges, or other damage. Rotate tires periodically to promote even wear.

Consider the type of work you're doing when selecting tires for your John Deere 3520. Different tire types offer varying levels of traction and durability for different applications. Ensure the tires are properly mounted and torqued to the correct specifications. When not in use, store your tractor in a shaded area to protect the tires from direct sunlight, which can cause them to crack and deteriorate over time. Also, be sure to check for damage to the tire valve and make sure the cap is installed properly.

Battery Maintenance

The battery is the heart of your John Deere 3520's electrical system, providing the power needed to start the engine and operate various electrical components. Regularly inspect the battery terminals for corrosion and clean them as needed with a baking soda and water solution. Ensure the battery cables are securely connected and in good condition. Check the battery's state of charge and recharge it as needed to maintain optimal performance.

If you plan to store your tractor for an extended period, disconnect the battery to prevent it from discharging. Consider using a battery maintainer to keep the battery charged during storage. Replace the battery when it shows signs of weakness or fails to hold a charge. Always dispose of used batteries properly according to local regulations. Batteries are a safety hazard, so be careful when disconnecting and reconnecting battery terminals.

Cooling System Maintenance

The cooling system is responsible for regulating the engine temperature and preventing overheating. Regularly check the coolant level and add coolant as needed. Inspect the radiator and cooling fan for debris and clean them as needed to ensure proper airflow. Check the condition of the radiator hoses and replace them if they are cracked, brittle, or leaking.

Periodically flush the cooling system and replace the coolant according to the manufacturer's recommendations. Use only coolant that meets John Deere's specifications to prevent corrosion and damage to the cooling system components. Inspect the water pump for leaks or signs of wear and replace it as needed. Overheating can cause serious damage to the engine, so address any cooling system issues promptly. Coolant can cause burns so be sure to wear proper protection to prevent injury.

Electrical System Maintenance

A well-maintained electrical system is crucial for the reliable operation of your John Deere 3520. Regularly inspect all wiring for damage or loose connections. Check the condition of the fuses and replace any that are blown. Ensure all lights and electrical accessories are functioning properly. If you experience any electrical issues, consult the wiring diagram in the service manual for troubleshooting assistance.

Keep the electrical components clean and free from moisture and corrosion. Protect the wiring from abrasion and damage by using cable ties and conduit where necessary. When working on the electrical system, disconnect the battery to prevent accidental shorts or electrical shocks. Consider using a multimeter to check for voltage and continuity when troubleshooting electrical problems. Before you begin any work with the electrical system, it is wise to consult with an expert.

Fuel System Maintenance

A clean and properly functioning fuel system is essential for optimal engine performance and fuel efficiency. Regularly inspect the fuel lines for leaks or damage. Replace the fuel filter as needed to prevent contaminants from entering the fuel system. Drain the fuel tank periodically to remove any water or sediment that may have accumulated.

Use only clean, fresh fuel that meets John Deere's specifications. Avoid using fuel that has been stored for an extended period, as it can degrade and cause problems. If you plan to store your tractor for an extended period, add a fuel stabilizer to the fuel tank to prevent fuel degradation. Inspect the fuel injectors for signs of clogging or damage and have them professionally cleaned or replaced as needed. Always be safe when handling and working with fuel, and consult with an expert if you are unsure.

Troubleshooting

Engine Problems

Engine problems are a common occurrence in tractor maintenance, and understanding the potential causes is crucial for efficient diagnosis and repair. Issues can range from a simple lack of fuel to more complex internal failures. Before attempting any repairs, always consult the tractor's operation manual for specific recommendations and safety precautions. Ignoring these precautions can lead to serious injury or further damage to the machine. Regularly scheduled maintenance, including oil changes and filter replacements, can significantly reduce the likelihood of engine problems arising in the first place.

A sputtering or rough-running engine can indicate several problems. Check the fuel filter for clogs and ensure the fuel lines are clear of obstructions. Air in the fuel system can also cause these symptoms. Bleeding the fuel system can resolve this issue, though you will need to locate the bleeding points in the service manual. Spark plugs, if applicable, should be inspected for fouling or damage. Faulty spark plugs will not provide sufficient spark to ignite the fuel/air mixture and can cause the engine to skip or misfire. Proper timing and carburetion (or fuel injection) are also essential for smooth engine operation. If any of these issues arise, consult the operator's manual for appropriate adjustment procedures or the location of your nearest service center.

Overheating is another common engine problem that needs immediate attention. Insufficient coolant levels, a malfunctioning thermostat, or a blocked radiator can all contribute to overheating. Always allow the engine to cool down completely before opening the radiator cap to avoid scalding. Check the radiator hoses for leaks or kinks that may restrict coolant flow. The water pump is also a prime suspect, as failure of the water pump can cause an overheating situation. A faulty water pump will not circulate the coolant effectively and could cause lasting damage to the engine if left unattended.

Transmission Problems

Transmission problems can manifest as difficulty shifting gears, slipping gears, or unusual noises during operation. Start by checking the transmission fluid level and condition. Low fluid levels can cause slipping, while contaminated fluid can damage internal components. Always use the correct type of transmission fluid as specified in the tractor's manual. Using the wrong fluid can lead to premature wear or even complete failure of the transmission.

If you experience difficulty shifting gears, the clutch may be the culprit. Check the clutch linkage for proper adjustment and look for signs of wear or damage. A worn clutch disc can cause slipping, making it difficult to transmit power to the wheels. It is also possible that the clutch could be stuck in the engaged or disengaged position which renders the tractor inoperable until the issue is resolved. Internal transmission problems, such as worn gears or bearings, may require professional repair. Attempting to disassemble the transmission without the proper tools and expertise can result in further damage or injury.

Unusual noises coming from the transmission, such as grinding or whining, can indicate serious internal damage. These noises should not be ignored, as continued operation can lead to catastrophic failure. Immediately cease operation and consult a qualified mechanic for diagnosis and repair. Ignoring the problem may also lead to other systems connected to the transmission failing and costing more to fix in the long run.

Hydraulic System Problems

The hydraulic system is crucial for operating implements such as loaders, mowers, and tillers. Problems in the hydraulic system can result in slow or weak implement operation, leaks, or complete failure. Begin by checking the hydraulic fluid level and condition. Low fluid levels can cause cavitation, leading to damage to the hydraulic pump. Contaminated fluid can damage seals and internal components.

Hydraulic leaks are a common problem and can be caused by damaged hoses, fittings, or seals. Inspect all hoses and fittings for signs of leaks or damage. Replace any damaged components immediately to prevent further fluid loss and potential environmental contamination. Be extremely careful when working with hydraulic systems, as high-pressure fluid can cause serious injury. If you find fluid leaking from the hydraulic pump, it may be time to either rebuild or replace the pump.

Slow or weak implement operation can be caused by a faulty hydraulic pump, a blocked filter, or a malfunctioning control valve. Check the hydraulic filter and replace it if it's dirty. A faulty control valve can restrict fluid flow, leading to reduced performance. Hydraulic cylinders, which actuate the implements, can also fail due to worn seals or damage. If a cylinder fails, the implement will only have partial functionality or become totally inoperable.

Electrical System Problems

Electrical problems can range from simple issues like a blown fuse to more complex wiring problems. A multimeter is an essential tool for diagnosing electrical issues. Start by checking the battery voltage and connections. Corroded battery terminals can prevent proper current flow. Clean the terminals and ensure they are securely connected. Always disconnect the negative terminal before working on the electrical system to prevent short circuits.

Blown fuses are often caused by short circuits or overload. Locate the fuse panel and check each fuse for continuity. Replace any blown fuses with the correct amperage rating. If a fuse blows repeatedly, there is likely a short circuit in the wiring. Trace the wiring and look for any signs of damage or chafing. Consult the wiring diagram in the tractor's manual to locate the source of the short.

Starting problems can be caused by a faulty starter motor, a weak battery, or a malfunctioning solenoid. Test the starter motor and solenoid to ensure they are functioning properly. A weak battery may need to be replaced. Check the charging system to ensure the battery is being properly charged while the engine is running. If the alternator fails, the battery will only last for a few hours of operation and could cause starting issues.

Steering Problems

Steering problems can significantly impact the safe operation of your tractor. Difficulty steering, excessive play in the steering wheel, or unusual noises are all signs that something is amiss. Start by checking the power steering fluid level if your tractor is equipped with power steering. Low fluid levels can cause stiff steering or a lack of power assist. Always use the recommended type of fluid.

Inspect the steering linkage for wear or damage. Worn tie rod ends, ball joints, or steering gears can cause excessive play in the steering. Replace any worn or damaged components to restore proper steering control. A loose or damaged steering gearbox can also cause steering problems. If the gearbox is damaged beyond repair, it may need to be replaced. If your tractor has hydraulic steering, you'll want to check the seals to ensure they are not leaking or damaged.

Unusual noises, such as grinding or squealing, can indicate internal problems in the steering system. These noises should be investigated immediately to prevent further damage. It's essential to ensure that the front tires have adequate and equal pressure to guarantee safe steering operation.

Brake Problems

Brake problems are a serious safety concern and should be addressed immediately. Weak brakes, uneven braking, or unusual noises indicate potential issues. Begin by checking the brake fluid level if your tractor has hydraulic brakes. Low fluid levels can indicate a leak in the system. Check the brake lines and calipers for any signs of leakage and repair as needed.

Inspect the brake pads or shoes for wear. Worn brake pads or shoes will reduce braking effectiveness. Replace them as necessary. Be sure to follow the proper procedure for bleeding the brakes after replacing brake components. Air in the brake lines can cause spongy brakes. Also, inspect the brake rotors to make sure they are not rusted, damaged or cracked. If the rotors have sustained any significant damage, be sure to replace them as well.

Uneven braking can be caused by a faulty brake caliper or cylinder. Replace any faulty components. Adjust the brake linkage to ensure equal braking force on both sides. Unusual noises, such as grinding or squealing, can indicate worn or damaged brake components. Failing to repair the brake system can have life-threatening consequences.

Starting Problems

Difficulty starting your tractor can be frustrating and time-consuming. Begin by checking the battery's condition. Use a multimeter to check the voltage and ensure it's within the proper range (typically around 12.6 volts for a fully charged 12-volt battery). If the voltage is low, attempt to jump-start the tractor or recharge the battery using a battery charger. If your tractor struggles to start after sitting for weeks at a time, you may need to attach a battery tender when the tractor is not in use to provide enough power to start each time.

Check the starter motor connections for corrosion or looseness. Clean and tighten the connections as needed. If the starter motor clicks but doesn't turn the engine over, it may be faulty. A faulty solenoid can also prevent the starter motor from engaging. Test the starter motor and solenoid to ensure they are functioning properly. Consult your tractor's service manual for the correct testing procedure or seek assistance from a qualified mechanic.

In cold weather, starting problems can be exacerbated by the thickening of engine oil. Consider using a lower viscosity oil during winter months or installing an engine block heater to warm the engine before starting. Also, ensure that your fuel is appropriate for cold weather conditions, as some fuels can gel at low temperatures, preventing them from flowing properly. Check the glow plugs (if equipped) to ensure they are functioning correctly, as they are essential for preheating the combustion chamber in diesel engines. The glow plugs are one of the most important parts when starting a tractor in freezing weather.

Repair Procedures

Engine Repair

The heart of your John Deere 3520 is its engine, and proper maintenance and timely repairs are critical for its longevity and performance. Before beginning any engine repair, always disconnect the negative battery cable to prevent accidental electrical shorts. Thoroughly clean the engine exterior to avoid contaminants entering the engine during disassembly. It's highly recommended to have the service manual readily available and consult it frequently during the repair process. Note any unusual noises or vibrations before disassembly as these can provide valuable clues about the underlying issue. Always use high-quality replacement parts that meet or exceed original John Deere specifications. When dealing with engine repairs, understanding the specific components and their functions is paramount. For example, if you are addressing a head gasket issue, carefully inspect the cylinder head and block surfaces for any warping or damage. Use a straight edge and feeler gauges to check for flatness and consult the service manual for acceptable tolerances. If the head or block is warped beyond these limits, it needs to be resurfaced by a qualified machine shop. Always use a new head gasket when reassembling, and torque the head bolts in the specified sequence and to the proper torque specifications using a calibrated torque wrench. Improper torquing can lead to leaks and engine damage.

Transmission Repair

The transmission is the powertrain component responsible for transferring engine power to the wheels, and its proper operation is essential for the tractor's functionality. Prior to commencing any transmission repair, drain the transmission oil and inspect it for metal shavings or debris. The presence of such contaminants indicates internal wear and damage. Thoroughly clean the transmission exterior before disassembly to prevent dirt from entering the internal components. Take pictures or make detailed sketches of the transmission assembly before disassembly to aid in reassembly. When performing transmission repairs, pay close attention to the condition of the gears, bearings, and seals. Inspect the gear teeth for wear, pitting, or breakage. Replace any worn or damaged gears to prevent further damage to the transmission. Check the bearings for smoothness and replace any that feel rough or have excessive play. Always use new seals when reassembling the transmission to prevent leaks. When reassembling the transmission, ensure that all parts are properly lubricated with the correct type of transmission oil as specified in the service manual.

Hydraulic System Repair

The hydraulic system is integral to the operation of many tractor functions, including the loader, hitch, and power steering. When working on the hydraulic system, ensure the tractor is parked on a level surface and the engine is turned off. Relieve the hydraulic pressure by cycling the control levers several times with the engine off. Before disconnecting any hydraulic lines, clean the surrounding area to prevent contaminants from entering the system. Always use the correct size and type of wrenches to avoid damaging the fittings. When repairing hydraulic cylinders, inspect the cylinder bore for scoring or damage. Replace the piston seals if they are worn or damaged to prevent leaks. When replacing hydraulic hoses, ensure that they are the correct length and pressure rating. Always use new O-rings and seals when reassembling hydraulic components. After completing the repairs, bleed the air from the hydraulic system by cycling the control levers several times. Check for leaks and tighten any loose fittings.

Electrical System Repair

The electrical system powers various tractor functions, including the starter, lights, and instruments. Before beginning any electrical repairs, disconnect the negative battery cable to prevent electrical shorts. Use a multimeter to diagnose electrical problems and trace circuits. Inspect the wiring harness for damaged or corroded wires. Clean the battery terminals and cable connections to ensure a good electrical connection. When replacing electrical components, use the correct type and rating of parts. When splicing wires, use proper crimping tools and connectors to ensure a secure and reliable connection. Protect the wiring harness with electrical tape or wire loom to prevent damage. After completing the repairs, test the electrical system to ensure that all functions are working properly. Check the fuses and replace any that are blown.

Steering System Repair

The steering system allows the operator to control the direction of the tractor. Before working on the steering system, ensure the tractor is parked on a level surface and the engine is turned off. Inspect the steering linkage for wear or damage. Check the steering fluid level and top it off if necessary. When repairing the steering system, inspect the steering gear for wear or damage. Replace any worn or damaged parts to ensure smooth and responsive steering. When reassembling the steering system, ensure that all parts are properly lubricated. After completing the repairs, test the steering system to ensure that it is working properly. Check for leaks and tighten any loose fittings.

Brake System Repair

The brake system allows the operator to safely stop the tractor. Before working on the brake system, ensure the tractor is parked on a level surface and the engine is turned off. Inspect the brake pads or shoes for wear. Check the brake fluid level and top it off if necessary. When repairing the brake system, inspect the brake cylinders for leaks or damage. Replace any worn or damaged parts to ensure proper braking performance. When reassembling the brake system, bleed the air from the brake lines. After completing the repairs, test the brake system to ensure that it is working properly.

Fuel System Repair

The fuel system delivers fuel to the engine for combustion. Before working on the fuel system, ensure the tractor is parked in a well-ventilated area and the engine is turned off. Disconnect the fuel lines and drain the fuel tank. Inspect the fuel lines for cracks or leaks. When repairing the fuel system, inspect the fuel pump for wear or damage. Replace any worn or damaged parts to ensure proper fuel delivery. When reassembling the fuel system, ensure that all connections are tight to prevent leaks. After completing the repairs, prime the fuel system and check for leaks.

Cooling System Repair

The cooling system regulates the engine temperature to prevent overheating. Before working on the cooling system, ensure the engine is cool. Drain the coolant from the radiator. Inspect the radiator hoses for cracks or leaks. When repairing the cooling system, inspect the water pump for wear or damage. Replace any worn or damaged parts to ensure proper coolant circulation. When reassembling the cooling system, ensure that all connections are tight to prevent leaks. After completing the repairs, refill the cooling system with the proper coolant mixture and check for leaks.

Detailed instructions with diagrams and torque specifications

Detailed instructions, diagrams and torque specifications for each of these procedures can be found in the John Deere 3520 Technical Manual. Always refer to the manual for the specific model and serial number of your tractor. The manual will provide detailed step-by-step instructions, exploded diagrams, and torque specifications for all components. Following these instructions carefully will ensure that the repairs are performed correctly and safely.

Component Removal and Installation

Prior to removing any component, thoroughly inspect the area around it, noting the location of any wires, hoses, or other connections. Disconnect these connections carefully, labeling them if necessary, to ensure proper reassembly. Use the correct tools for the job to avoid damaging the component or surrounding parts. When installing a new component, follow the torque specifications in the service manual to ensure proper tightness. Over-tightening can damage the component, while under-tightening can lead to leaks or failures. After installation, double-check all connections and test the system to ensure it is working properly.

Attachments and Accessories

Front-End Loader

The John Deere 3520 is a versatile tractor capable of handling a variety of tasks, and one of the most popular attachments is the front-end loader. This attachment significantly expands the tractor's functionality, allowing you to lift, move, and load materials like soil, gravel, mulch, and snow. The loader typically connects to the tractor's hydraulic system, providing the necessary power for lifting and dumping. Regular maintenance of the front-end loader is crucial for optimal performance and longevity, including checking hydraulic fluid levels, lubricating moving parts, and inspecting for any signs of damage or wear.

Before operating the front-end loader, thoroughly familiarize yourself with the controls and operating procedures outlined in the loader's specific manual, as well as the tractor's. Proper operation involves smooth and controlled movements to avoid overloading the loader arms or destabilizing the tractor. Always ensure the load is balanced within the bucket to prevent tipping, especially when operating on uneven terrain. Never exceed the loader's rated lifting capacity, as this can damage the hydraulic system or create a dangerous operating situation. Safety should always be your top priority when using a front-end loader.

Backhoe

For digging tasks, the backhoe attachment transforms the John Deere 3520 into a powerful excavation machine. Backhoes are commonly used for digging trenches, foundations, and other earthmoving applications. Like the front-end loader, the backhoe utilizes the tractor's hydraulic system for its operation. However, backhoes are usually mounted to the three-point hitch and connected to the Power Take-Off (PTO) system on the tractor to operate.

Operating a backhoe requires skill and precision. Before using a backhoe, ensure you understand the location of underground utilities to avoid damage or injury. Clear the work area of any obstacles and establish a safe operating zone. Smooth, controlled movements are essential to avoid jerky motions or overloading the backhoe's hydraulic system. Regular inspections of hydraulic lines, cylinders, and the backhoe frame are essential to catch wear or damage before it leads to a breakdown. Always consult the backhoe's specific manual for detailed operating instructions and safety precautions.

Mowing Decks

The John Deere 3520 is also well-suited for maintaining lawns and fields with the use of a variety of mowing deck attachments. These decks come in various sizes and configurations, including mid-mount and rear-mount options. The selection of the appropriate mowing deck depends on the size of the area to be mowed and the desired finish quality. Regular maintenance, such as blade sharpening and deck cleaning, is crucial for optimal performance. A sharp blade means an even cut and healthier grass.

When operating a mowing deck, always be aware of your surroundings. Clear the area of any debris, such as rocks, branches, or toys, which could be thrown by the blades. Always wear appropriate safety gear, including eye and ear protection. Adjust the cutting height according to the terrain and the desired grass length. Overlapping each pass slightly ensures a clean and even cut. Prioritize safety when mowing by keeping children and pets a safe distance from the operating tractor.

Tillers

For soil preparation, a tiller attachment can be invaluable. Tillers are used to break up and cultivate soil for planting gardens, food plots, or preparing seedbeds. These implements attach to the tractor's three-point hitch and are powered by the PTO. The rotating tines of the tiller churn the soil, creating a loose and aerated surface ideal for planting.

When using a tiller, start by making shallow passes and gradually increasing the depth as needed. Avoid tilling wet soil, as this can compact the soil and hinder plant growth. Clear the area of any large rocks or debris that could damage the tiller. Regular maintenance, such as checking the tines for wear and lubricating moving parts, is essential for optimal performance. Follow the manufacturer's recommendations for operating speed and tilling depth to achieve the best results. If the soil is very compact, you may need to make more than one pass.

Snow Blowers

In regions with significant snowfall, a snow blower attachment is a lifesaver. Snow blowers effectively clear driveways, walkways, and other areas of snow, saving time and effort compared to manual shoveling. These attachments are typically mounted to the front of the tractor and powered by the PTO.

Before operating a snow blower, ensure that the area is clear of any obstacles that could be damaged or thrown by the blower. Adjust the chute to direct the snow away from buildings, vehicles, and people. Avoid operating the snow blower on gravel surfaces, as this can damage the blower and throw projectiles. Regular maintenance, such as lubricating moving parts and checking the shear pins, is essential for reliable operation. In snowy climates, a snowblower attachment turns the John Deere 3520 into a must-have tool.

Other Attachments

Beyond the common attachments listed above, the John Deere 3520 is compatible with a wide array of other implements. These include box blades for grading and leveling, rotary cutters for brush hogging, seeders for planting, and sprayers for applying herbicides and pesticides. The versatility of the John Deere 3520 allows it to be adapted to a variety of different task.

When considering any attachment, always consult the tractor's operator's manual and the attachment's specific manual to ensure compatibility and proper operation. Regular maintenance of all attachments is crucial for optimal performance and longevity. Understanding the capabilities and limitations of each attachment is key to maximizing the utility of your John Deere 3520. Always prioritize safety when operating any attachment and follow all safety precautions outlined in the manuals.

Wiring Diagrams

Parts List

Understanding the component parts of your John Deere 3520 tractor is crucial for effective maintenance and repair. This chapter provides a comprehensive parts list, accompanied by exploded diagrams, to aid in identifying and ordering the correct components. Always refer to your tractor's specific model and serial number when ordering parts to ensure compatibility. Incorrect parts can lead to decreased performance, potential damage, and safety hazards. We strongly recommend using genuine John Deere parts to maintain the quality and longevity of your tractor. The use of aftermarket parts may void your warranty and could compromise the overall reliability of the machine. Furthermore, proper identification and handling of parts is paramount for safe and efficient repairs.

Engine Components: The engine is the heart of your 3520. Key components include the cylinder head, pistons, connecting rods, crankshaft, camshaft, fuel injectors, and oil pump. Exploded diagrams will illustrate the precise assembly of these components, highlighting the location of critical gaskets and seals. Each diagram will be accompanied by a detailed parts list, including part numbers and descriptions, allowing you to easily identify and order the necessary replacements. Remember to always disconnect the battery before working on any electrical components of the engine. Thoroughly clean any engine parts before reassembly to prevent contamination and ensure proper functionality. Correct torque specifications are essential when tightening engine components; refer to the torque chart provided later in this manual.

Transmission and Drivetrain: This section covers the transmission, axles, differential, and PTO (Power Take-Off) system. The transmission is responsible for transferring power from the engine to the wheels, and understanding its components is vital for troubleshooting performance issues. Exploded views will detail the arrangement of gears, bearings, and shafts within the transmission housing. These diagrams will show the proper order for disassembly and reassembly, preventing damage to delicate parts. The PTO system, used for powering implements, requires careful attention to lubrication and alignment. Regularly inspect the PTO shaft and clutch for wear and damage to prevent unexpected failures. Ensure the PTO shield is always in place during operation to protect against entanglement hazards.

Hydraulic System: The hydraulic system provides power for the loader, three-point hitch, and other hydraulically operated components. Key parts include the hydraulic pump, control valves, cylinders, and hoses. Understanding the hydraulic circuit diagram is essential for diagnosing leaks and troubleshooting performance problems. Always relieve pressure in the hydraulic system before disconnecting any lines or components to prevent injury. Use caution when handling hydraulic fluid, as it can be harmful if ingested or comes into contact with skin. Regularly check the hydraulic fluid level and condition, and replace it according to the recommended service intervals. Correct hose routing and secure connections are essential to prevent leaks and ensure efficient system operation.

Electrical System: The electrical system encompasses the battery, alternator, starter motor, wiring harness, and various sensors. These components are responsible for powering the tractor's lights, starting the engine, and controlling various functions. Exploded diagrams will detail the location of fuses, relays, and sensors within the electrical system. Use a multimeter to test circuits and components to diagnose electrical problems. Always disconnect the battery before working on any electrical components. Clean battery terminals regularly to prevent corrosion and ensure proper electrical contact. Refer to the wiring diagram to trace circuits and identify faulty components.

Storage

Preparing the tractor for short-term and long-term storage

Properly preparing your John Deere 3520 for storage, whether it's for a few weeks during the off-season or for several months over the winter, is crucial for maintaining its performance and longevity. Neglecting this important step can lead to a multitude of problems, including battery drain, fuel system degradation, rust formation, and even damage to sensitive components. This chapter outlines the necessary procedures for both short-term and long-term storage, ensuring your tractor is ready to work when you need it. By following these steps, you'll minimize the risk of costly repairs and maximize the lifespan of your valuable equipment.

Short-Term Storage (1-3 Months): For short periods, the focus is on preventing fuel degradation and battery discharge. First, fill the fuel tank completely to minimize condensation and prevent rust formation within the tank. Consider adding a fuel stabilizer to the tank to further prevent fuel degradation, especially if the fuel has a high percentage of bio-diesel. Disconnect the negative battery cable to prevent parasitic drain, or better yet, use a battery maintainer to keep the battery topped up. Park the tractor on a level surface, preferably indoors, to protect it from the elements and reduce stress on the tires. Periodically inspect the tractor for any signs of leaks or damage during the storage period.

Long-Term Storage (3+ Months): Long-term storage requires more extensive preparation to safeguard against a wider range of potential issues. In addition to the steps for short-term storage, thoroughly clean the tractor, removing any dirt, debris, or plant material. Pay particular attention to the cooling system, ensuring the radiator is free of obstructions and the coolant is at the proper level and has adequate freeze protection. Change the engine oil and filter to remove contaminants that could corrode internal engine parts during storage. Grease all lubrication points to protect against rust and corrosion. Release the tension on the belts to prevent them from stretching or cracking.

Another crucial step for long-term storage is to properly protect the tires. Ideally, lift the tractor off the ground using jack stands to prevent flat spots and tire degradation. If that's not possible, inflate the tires to the maximum recommended pressure, as indicated on the tire sidewall. Cover the tires to protect them from direct sunlight, which can cause cracking and deterioration. Also, consider rodent control measures, such as placing traps or using repellents around the storage area, as rodents can damage wiring and other components. Don’t forget to close or seal off any openings to prevent them from entering the tractor.

Finally, before putting the tractor back into service after storage, it's essential to perform a thorough inspection. Check all fluid levels, including engine oil, coolant, hydraulic fluid, and transmission fluid. Inspect the tires for proper inflation and any signs of damage. Reconnect the battery and check its voltage. Start the engine and listen for any unusual noises. Run the tractor for a few minutes to circulate fluids and ensure all systems are functioning correctly. By taking these precautions, you can ensure your John Deere 3520 is ready to work hard whenever you are.