This service manual provides comprehensive technical information and procedures for the maintenance, repair, and overhaul of the KUBOTA M135GX-III tractor. It is intended for use by qualified technicians with a thorough understanding of agricultural machinery and internal combustion engines. The manual is structured to guide you through various service operations, from routine maintenance to complex component replacements. Accurate diagnosis and proper repair techniques are crucial for ensuring the longevity and optimal performance of your tractor. Please read this manual carefully and familiarize yourself with its contents before attempting any service work.
This manual is not a substitute for proper training and experience. Always use appropriate tools and safety equipment when performing any service procedure. Throughout this manual, you will find specific torque specifications, fluid capacities, and other critical data. Adhering to these specifications is essential for preventing damage to tractor components and ensuring safe operation. Regularly updating your knowledge and consulting Kubota's official technical bulletins will further enhance your ability to effectively service the M135GX-III tractor.
Safety is paramount when working on any machinery, and the KUBOTA M135GX-III is no exception. Before starting any maintenance or repair procedure, thoroughly review the safety precautions outlined in this manual and in the tractor's operator's manual. Always disconnect the battery ground cable before working on the electrical system or performing any operation that could cause a short circuit. This will prevent accidental starting and potential electrical shock. Never work under a tractor supported only by a jack; always use properly rated jack stands.
When working with hydraulic systems, remember that hydraulic fluid is under high pressure and can cause serious injury. Relieve all pressure before disconnecting any hydraulic lines or components. Wear appropriate eye protection and gloves to prevent fluid from contacting your skin. Be aware of moving parts and always keep your hands and clothing clear of them when the engine is running. Fuel, oil, and other fluids are flammable; always keep them away from open flames and sparks. Work in a well-ventilated area to avoid inhaling harmful fumes.
The KUBOTA M135GX-III is a complex machine, and understanding its basic systems is crucial for effective maintenance. This manual covers the engine, transmission, hydraulic system, electrical system, and other key components. Regular maintenance is essential for preventing premature wear and tear and maximizing the tractor's lifespan. Following the recommended maintenance schedule will help you identify potential problems before they become major issues.
The maintenance schedule outlines the frequency for tasks such as oil changes, filter replacements, lubrication, and inspections. It is important to adhere to this schedule, even if the tractor is not used frequently. Some components, such as rubber hoses and belts, can deteriorate over time, regardless of usage. Keep accurate records of all maintenance performed, including dates, services performed, and parts used. This will help you track the tractor's maintenance history and identify any recurring problems. Using genuine Kubota parts is highly recommended to ensure optimal performance and reliability.
Removing and installing the engine in your Kubota M135GX-III is a significant undertaking, requiring careful planning and execution. Before starting, ensure the tractor is parked on a level surface, the parking brake is engaged, and the engine is cool to prevent burns. Disconnect the battery cables, starting with the negative terminal, to avoid any electrical shorts during the process. Gather all necessary tools, including wrenches, sockets, jacks, and lifting equipment rated for the engine's weight. Thoroughly consult the exploded diagrams in this manual to understand the location of all connections and mounting points before you start to disassemble the unit.
The first step involves disconnecting all systems attached to the engine. This includes the fuel lines, coolant hoses, electrical wiring harnesses, and the exhaust system. Carefully label each connection with tape and a marker to ensure proper reassembly. Drain all fluids, including engine oil and coolant, into appropriate containers for proper disposal. Remove the hood and any other body panels that obstruct access to the engine. Next, disconnect the driveshaft or PTO shaft, if applicable, and any linkages connected to the transmission.
Using a suitable engine hoist, carefully lift the engine from its mounts. Ensure the lifting chains are properly secured to the engine's lifting points. Gradually raise the engine, checking for any remaining connections that may have been overlooked. Once the engine is clear of the tractor frame, carefully move it to a stable work area for further service or repair. Installation is the reverse of removal, but take extra care to align all components correctly and torque fasteners to the specified values outlined in this manual. Always replace gaskets and seals to ensure a leak-free installation. Finally, check all fluid levels and electrical connections before starting the engine.
The cylinder head is a critical component of the engine, responsible for sealing the cylinders and housing the valves. Over time, the cylinder head can develop cracks, warpage, or valve seat issues. Before starting any cylinder head service, ensure the engine is cool and the fuel system is depressurized. Remove the cylinder head from the engine block, following the removal procedure outlined in the engine removal section. Once the cylinder head is removed, thoroughly clean it using a parts washer and degreaser.
Inspect the cylinder head for any signs of cracks, particularly around the valve seats and spark plug holes (if applicable). Use a straight edge and feeler gauge to check for warpage of the cylinder head surface. If warpage exceeds the manufacturer's specifications, the cylinder head may need to be resurfaced by a machine shop. Examine the valve guides for wear and replace them if necessary. Inspect the valve seats for pitting or wear. Valve seat grinding or replacement may be required to ensure proper valve sealing.
Clean the valves and inspect them for damage, such as bent stems or burned faces. Lap the valves into the valve seats using lapping compound and a valve lapping tool. This will ensure a tight seal between the valve and the seat. Install new valve stem seals to prevent oil from entering the combustion chamber. Reassemble the cylinder head, ensuring all components are properly lubricated. Torque the cylinder head bolts to the manufacturer's specifications in the correct sequence. Adjust the valve clearance according to the specifications outlined in this manual.
The fuel system on the Kubota M135GX-III is responsible for delivering fuel to the engine at the correct pressure and volume. A properly functioning fuel system is essential for optimal engine performance and fuel efficiency. Start by visually inspecting all fuel lines for cracks, leaks, or damage. Replace any damaged fuel lines. Check the fuel filter for clogs or contamination. Replace the fuel filter as needed. Inspect the fuel pump for proper operation. The fuel pump should deliver fuel at the specified pressure and volume.
The fuel injectors are responsible for atomizing the fuel and injecting it into the combustion chamber. Clogged or dirty fuel injectors can cause poor engine performance, reduced fuel efficiency, and increased emissions. Remove the fuel injectors and clean them using a fuel injector cleaning kit. Inspect the fuel injectors for damage, such as cracked bodies or leaking seals. Replace any damaged fuel injectors. Install the fuel injectors, ensuring they are properly seated and sealed.
If your tractor is equipped with a fuel injection pump, it will require special attention. The fuel injection pump is a precision component that requires specialized tools and knowledge to repair. If you suspect a problem with the fuel injection pump, it is best to take it to a qualified diesel mechanic for repair. After performing any fuel system repairs, bleed the fuel system to remove any air that may have entered the system. Start the engine and check for leaks.
The cooling system prevents the engine from overheating by circulating coolant through the engine block and radiator. Regular maintenance of the cooling system is crucial for preventing engine damage and ensuring long engine life. Begin by visually inspecting the radiator for leaks or damage. Check the coolant level in the radiator and reservoir. Add coolant as needed, using a 50/50 mixture of antifreeze and distilled water.
Inspect the coolant hoses for cracks, leaks, or swelling. Replace any damaged coolant hoses. Check the thermostat for proper operation. The thermostat should open and close at the specified temperature. A malfunctioning thermostat can cause the engine to overheat or run too cold. Periodically flush the cooling system to remove accumulated sediment and debris. Use a radiator flush solution according to the manufacturer's instructions.
Inspect the water pump for leaks or unusual noises. The water pump is responsible for circulating coolant through the engine. A failing water pump can cause the engine to overheat. Consider replacing the water pump during major cooling system maintenance. Check the fan belt for wear and tension. A loose or worn fan belt can reduce the efficiency of the cooling system. Adjust the fan belt tension as needed. Periodically inspect the radiator fins for debris and clean them with a soft brush. Always dispose of used coolant properly.
The lubrication system ensures that all moving parts within the engine receive adequate lubrication, minimizing friction and wear. Proper lubrication is vital for engine longevity and reliability. Regularly check the engine oil level using the dipstick. Add oil as needed, using the correct type and grade of oil specified in this manual. Change the engine oil and filter at the recommended intervals.
Inspect the oil filter for damage or leaks. Use a high-quality oil filter designed for your Kubota M135GX-III. A clogged oil filter can restrict oil flow and damage the engine. Check the oil pressure gauge for proper operation. Low oil pressure can indicate a problem with the lubrication system. Inspect the oil cooler for leaks or damage. The oil cooler helps to keep the engine oil cool, especially during heavy use.
Analyze oil samples regularly to monitor the condition of the engine and identify potential problems early. Oil analysis can reveal the presence of contaminants, wear metals, or excessive oil degradation. Consult with a reputable oil analysis laboratory for interpretation of the results. Address any lubrication system issues promptly to prevent serious engine damage. Remember that preventative maintenance is the best way to ensure the long life and efficient operation of your Kubota engine.
The gearbox is the heart of your Kubota M135GX-III's transmission, responsible for transferring power from the engine to the wheels at varying speeds and torques. Before undertaking any disassembly of the gearbox, it is crucial to ensure the tractor is safely supported and the transmission oil is completely drained. Begin by removing the necessary external components, such as the PTO shaft and any surrounding guards or covers, carefully documenting the location and orientation of each part to facilitate reassembly. Pay close attention to any wiring or hydraulic lines that may be connected to the gearbox, disconnecting them with precision and securing them to prevent damage or fluid leaks.
Once the external components are removed, you can proceed to separate the gearbox halves. This often involves removing a series of bolts and potentially using specialized pullers or separators to overcome any tight seals or corrosion. As you disassemble the gearbox, meticulously label and organize each gear, bearing, shaft, and other internal component. A clean and organized workspace is paramount to prevent confusion and ensure accurate reassembly. Note the position and shimming of each gear and bearing to maintain proper gear mesh and bearing preload during reassembly.
Assembly of the gearbox is the reverse of the disassembly process, but requires careful attention to detail and precise torque specifications. Ensure all components are thoroughly cleaned and inspected for wear or damage before reassembly. Apply fresh lubricant to all moving parts and seals to minimize friction and prevent premature wear. When reassembling the gearbox halves, use new gaskets or seals and tighten the bolts to the manufacturer's specified torque values in a crisscross pattern to ensure even pressure distribution. After the gearbox is fully assembled, refill the transmission with the correct type and quantity of oil, and carefully test the functionality of each gear to ensure smooth and proper operation.
The clutch is a vital component in the M135GX-III, controlling the engagement and disengagement of the engine from the transmission. Over time, the clutch can wear down, leading to slippage, difficulty shifting gears, or complete failure to engage. Regular clutch adjustment is crucial to maintaining optimal performance and prolonging the life of the clutch assembly. Begin by consulting the service manual to identify the specific adjustment points and procedures for your tractor model. Typically, this involves adjusting the clutch pedal free play or linkage to ensure proper engagement and disengagement.
If simple adjustments fail to resolve clutch issues, it may be necessary to inspect and repair or replace the clutch assembly. This requires removing the transmission and carefully disassembling the clutch housing. Inspect the clutch disc for wear, cracks, or oil contamination. Check the pressure plate for even wear and proper spring tension. The throw-out bearing should be smooth and quiet, and the pilot bearing or bushing in the flywheel should be properly lubricated and free from excessive wear. Replace any worn or damaged components with genuine Kubota parts to ensure proper fit and performance.
When reassembling the clutch, use a clutch alignment tool to center the clutch disc to the pilot bearing/bushing to ensure proper alignment with the input shaft of the transmission. Torque the pressure plate bolts to the manufacturer's specified torque values in a crisscross pattern. After reassembling the transmission, readjust the clutch pedal free play and linkage to ensure proper engagement and disengagement. Test the clutch thoroughly under various operating conditions to confirm that it is functioning smoothly and reliably.
The Power Take-Off (PTO) system allows the tractor to power implements, and problems with the PTO can significantly impact the tractor's functionality. When troubleshooting PTO issues, start by checking the PTO lever or switch to ensure it is properly engaged. Verify that the PTO shaft is securely connected to the implement and that there are no obstructions preventing it from rotating. Inspect the PTO driveline for damage or excessive wear, including the universal joints, slip clutch, and any safety shields. A damaged driveline can cause vibrations, noise, and even complete PTO failure.
If the PTO fails to engage, check the PTO clutch or brake mechanism. A worn or damaged PTO clutch can prevent the PTO shaft from rotating, while a malfunctioning brake can prevent it from disengaging. Consult the service manual for instructions on how to inspect and adjust the PTO clutch and brake. Look for leaks in the hydraulic system that controls the PTO engagement mechanism. Low hydraulic pressure can prevent the PTO from engaging fully or cause it to slip under load.
Electrical problems can also cause PTO malfunctions. Check the PTO switch, wiring, and any related relays or solenoids for proper operation. Use a multimeter to test for continuity and voltage at the appropriate terminals. A faulty switch or wiring harness can prevent the PTO from engaging. If you suspect an internal problem with the PTO gearbox, such as worn gears or bearings, it may be necessary to disassemble the PTO unit for inspection and repair. Remember to consult the service manual for detailed instructions and torque specifications for PTO disassembly and assembly.
The hydraulic pump is the heart of your Kubota M135 GX-III's hydraulic system, responsible for providing the necessary fluid flow and pressure to operate various implements and systems. Regular maintenance and timely repairs are crucial to ensuring its longevity and optimal performance. Neglecting the pump can lead to a decrease in hydraulic power, sluggish implement operation, and potentially costly repairs down the line. Before undertaking any pump service, always consult the specific service manual for your M135 GX-III, as variations may exist based on model year and configuration. Pay close attention to safety precautions, especially when dealing with pressurized hydraulic systems.
A common service task involves inspecting the hydraulic pump for leaks. Check the pump housing, fittings, and seals for any signs of fluid seepage. Leaks not only reduce hydraulic efficiency but also pose an environmental hazard. If leaks are found, determine the source and replace the affected seals or fittings. Disassembly of the hydraulic pump itself should only be performed by qualified technicians with the proper tools and knowledge. The internal components are precision-engineered and require careful handling to avoid damage.
Another important aspect of hydraulic pump service is checking the fluid level and condition. Low fluid levels can cause the pump to cavitate, leading to damage and reduced performance. Always use the correct type of hydraulic fluid specified in your service manual. The fluid should be clean and free from contaminants. Over time, hydraulic fluid can degrade and become contaminated with dirt, moisture, and metal particles. Regularly changing the hydraulic fluid and filter will help protect the pump and other hydraulic components from wear and tear.
The valve body is a critical component that directs hydraulic fluid flow to various circuits within the system, controlling the operation of implements such as loaders, mowers, and other attachments. Proper diagnosis of valve body issues is essential for maintaining optimal hydraulic performance. Symptoms of a malfunctioning valve body can include slow implement response, erratic movement, and complete failure of a specific hydraulic function. These issues can stem from internal leaks, stuck spools, or damaged seals within the valve body.
When troubleshooting a valve body issue, begin by visually inspecting the unit for any external damage or leaks. Check the control linkages and connections to ensure they are properly adjusted and free from binding. A pressure gauge can be used to test the hydraulic pressure at various points in the system to pinpoint the location of the problem. A pressure that's too low or too high can show that something is amiss. Keep in mind that many valve bodies contain multiple circuits, and diagnosing the specific circuit causing the problem will save time and effort.
If the valve body needs to be disassembled, be extremely careful to document the position and orientation of all internal components. These are precision-machined parts, and incorrect reassembly can lead to further damage. It's best to only disassemble the valve body in a clean environment to prevent the introduction of dirt or debris. When inspecting the internal components, look for signs of wear, scoring, or damage to the spools and bores. Replace any worn or damaged parts with genuine Kubota replacement parts to ensure proper operation and longevity. After reassembly, perform a thorough functional test to verify that all circuits are operating correctly.
Hydraulic cylinders are used throughout the Kubota M135 GX-III to provide the linear force required for various operations, such as lifting, tilting, and steering. Over time, hydraulic cylinders can develop leaks or experience damage to the rod, barrel, or seals. Signs of a failing hydraulic cylinder include slow or jerky movement, excessive leakage, and the inability to hold a load. Addressing these issues promptly is crucial to preventing further damage and ensuring safe operation of the equipment.
Before attempting to repair a hydraulic cylinder, carefully inspect it for any visible damage. Check the rod for bends, dents, or corrosion. Inspect the barrel for cracks or distortions. Leaks often occur at the rod seal or at the connections between the barrel and the end caps. Before disconnecting the cylinder, relieve the hydraulic pressure in the system to prevent injury. When disconnecting the hydraulic lines, cap the ends to prevent contamination.
Disassembly of a hydraulic cylinder requires special tools, such as a gland wrench, to remove the end caps. Be careful not to damage the threads or seals during disassembly. Once the cylinder is disassembled, inspect the internal components for wear or damage. The most common failure points are the rod seal, piston seal, and wiper seal. Replace these seals with genuine Kubota replacement parts. When reassembling the cylinder, lubricate the seals with hydraulic fluid to prevent damage during installation. Torque the end caps to the specifications in the service manual. After reassembly, test the cylinder for leaks and proper operation before reinstalling it on the equipment.
Hydraulic leaks are a common problem in heavy machinery and can lead to a decrease in efficiency, increased operating costs, and potential environmental hazards. Identifying and addressing hydraulic leaks promptly is crucial for maintaining the performance and longevity of the Kubota M135 GX-III. Leaks can occur at various points in the hydraulic system, including fittings, hoses, cylinders, pumps, and valve bodies. Finding these leaks fast can help with preventing expensive fixes to the machine.
When troubleshooting hydraulic leaks, begin by visually inspecting the entire hydraulic system for any signs of fluid seepage. Look for wet spots, drips, or puddles of hydraulic fluid. Pay close attention to areas where fittings are located, as these are common leak points. Clean the area around the suspected leak to make it easier to identify the source. Use a clean rag or paper towel to wipe the area, then observe to see where the fluid reappears. Be sure to review hoses, seals, and metal lines for cracks or damage.
Once you have identified the source of the leak, take the necessary steps to repair it. If the leak is at a fitting, try tightening it first. If that doesn't stop the leak, the fitting may need to be replaced. Damaged hoses should be replaced immediately. Leaks in cylinders, pumps, or valve bodies may require disassembly and repair or replacement of seals or other internal components. Always use genuine Kubota replacement parts to ensure proper fit and performance. After completing the repair, thoroughly clean the area to remove any residual hydraulic fluid. Monitor the area closely for any new leaks.
Understanding the Kubota M135GX-III's wiring diagram is crucial for effective electrical troubleshooting and repair. The diagram isn't just a map; it's a language. Each line, symbol, and annotation represents a specific wire, component, and connection within the electrical system. Familiarizing yourself with the standard Kubota electrical symbols is the first step. Knowing what each symbol represents – from relays and fuses to sensors and solenoids – allows you to trace circuits and identify potential faults. Furthermore, pay close attention to wire colors and gauge sizes, as these are often indicated on the diagram and are vital for correct wire identification and replacement.
The Kubota wiring diagrams often include multiple sheets, detailing various systems and subsystems. Learning how to navigate these sheets efficiently is key. Start with the section related to the component you're troubleshooting. Trace the circuit backwards from the component to the power source and ground connection, looking for breaks, shorts, or other anomalies along the way. Using a multimeter, you can then verify the voltage, current, and resistance at various points in the circuit, comparing your readings to the specifications outlined in the service manual to pinpoint the exact location of the problem.
Beyond just tracing wires, understanding the logic of the circuit is essential. Many modern tractor electrical systems are interconnected and rely on multiple sensors and control modules to function correctly. If one sensor fails, it can affect the operation of other systems. The wiring diagram will show how these systems are connected and how they interact. Analyzing the circuit's functionality and the sequence of operations allows you to anticipate the expected behavior of each component, helping you to more accurately diagnose and resolve complex electrical issues. Regularly consulting the diagram during troubleshooting will significantly reduce diagnostic time and prevent costly errors.
A faulty starting system is a common issue with tractors, often leaving you stranded when you need the machine most. Begin your diagnostic process by confirming the battery's condition. Ensure the battery voltage is within the specified range (typically 12.6V or higher when fully charged) and that the terminals are clean and free of corrosion. A weak or discharged battery is often the culprit, so test it under load using a battery load tester to determine its capacity. Remember that a seemingly good battery can still fail under the high current demand of the starting system.
If the battery is in good condition, proceed to check the starter solenoid and starter motor. When the key is turned to the start position, you should hear a distinct "click" from the solenoid. If no click is heard, the solenoid itself may be faulty or it may not be receiving power from the ignition switch or safety interlock system. Use a multimeter to verify voltage at the solenoid terminals. If the solenoid clicks but the starter motor doesn't engage, the starter motor may be faulty. The starter motor draws a significant amount of current, so a poor connection anywhere in the circuit can prevent it from working properly. Check all cables and connections for tightness and corrosion.
The safety interlock system, which prevents the tractor from starting in gear or with the PTO engaged, is another common source of starting problems. These interlock switches can become corroded or damaged over time, preventing the starting circuit from completing. Consult the wiring diagram to locate the interlock switches (often located on the seat, gear shift lever, and PTO lever) and use a multimeter to test their continuity when the corresponding lever is in the correct starting position. If any interlock switch is faulty, replace it with a new one. Also consider checking the condition of the ignition switch itself, as a worn switch can prevent the proper voltage from reaching the starter solenoid.
A properly functioning charging system is vital to keeping your Kubota M135GX-III's battery charged and its electrical components running smoothly. The charging system consists primarily of the alternator, voltage regulator, and battery. Regularly inspect the alternator belt for wear, cracks, or slippage. A loose or damaged belt will prevent the alternator from spinning at the correct speed, resulting in undercharging. Ensure the belt tension is within the manufacturer's specifications, using a belt tension gauge for accurate measurement. Replace the belt if it shows any signs of damage.
Check the alternator output voltage with the engine running. A healthy alternator should produce between 13.5 and 14.5 volts at the battery terminals. If the voltage is significantly lower or higher than this range, the voltage regulator may be faulty. The voltage regulator controls the alternator's output to prevent overcharging or undercharging the battery. In some cases, the alternator itself may be the problem, especially if it's producing excessive noise or has visibly damaged components. Always disconnect the battery before removing or installing the alternator to prevent electrical shorts. If possible, remove the alternator and take it to a local auto electric shop for testing and possible rebuild or replacement.
Don't overlook the importance of clean and secure connections in the charging system. Corroded battery terminals, loose alternator wires, or damaged ground connections can all impede the flow of current and lead to charging problems. Clean the battery terminals with a wire brush and apply a corrosion inhibitor to prevent future build-up. Inspect all wiring and connectors in the charging system for damage and repair or replace them as needed. Ensuring proper grounding is also essential. Check the ground strap connections between the engine, chassis, and battery for corrosion or looseness, tightening or cleaning them as required.
Properly functioning lights are essential for safe operation of your Kubota M135GX-III, especially during nighttime or low-visibility conditions. Start by visually inspecting all lights – headlights, taillights, turn signals, and warning lights – to ensure that the bulbs are in good condition and properly seated in their sockets. A blown bulb is the most common cause of a lighting problem. Replace any burnt-out bulbs with the correct type and wattage, as specified in the owner's manual. Always disconnect the power before replacing a bulb to avoid electrical shock.
If a bulb is good but the light still doesn't work, check the wiring and connections. Use a multimeter to verify that voltage is reaching the bulb socket. If there is no voltage, trace the circuit back to the switch or fuse box, looking for breaks, shorts, or loose connections. Corroded connectors are a common issue, especially in agricultural environments. Clean the connectors with a wire brush or electrical contact cleaner and apply a dielectric grease to prevent future corrosion. Replace any damaged or corroded wiring with new wiring of the same gauge.
Switches are another potential point of failure in the lighting system. Test the headlight switch, turn signal switch, and any other relevant switches to ensure they are functioning correctly. Use a multimeter to check the continuity of the switch in the "on" and "off" positions. If the switch is faulty, replace it with a new one. Finally, remember to check the grounding of the lights. A poor ground connection can prevent the lights from working properly. Ensure that the light housings are securely grounded to the chassis. Clean and tighten any ground connections that appear corroded or loose.
Fuses and relays are essential components in the electrical system, protecting circuits from overloads and controlling the operation of various electrical devices. Understanding their location and function is crucial for troubleshooting electrical problems. The fuse box is typically located under the dashboard or near the battery. Consult the operator's manual to identify the specific location of the fuse box on your Kubota M135GX-III. Once located, remove the fuse box cover to access the fuses and relays. Each fuse and relay is typically labeled with its corresponding circuit or function, allowing you to quickly identify the fuse or relay associated with a particular problem.
When diagnosing an electrical problem, always start by checking the fuses associated with the affected circuit. Use a fuse puller to remove the fuse and visually inspect it for a blown filament. A blown fuse will have a broken or blackened filament. If a fuse is blown, replace it with a new fuse of the same amperage rating. Never use a fuse with a higher amperage rating, as this could damage the circuit. If the fuse blows again immediately after replacement, there is likely a short circuit in the wiring or a faulty component in the circuit. Investigate further to identify and repair the short circuit or replace the faulty component.
Relays are electromechanical switches that are used to control high-current circuits with low-current control signals. They are commonly used to control the starter motor, headlights, and other high-power devices. If a relay is suspected of being faulty, you can test it using a multimeter. Check the continuity of the coil circuit and the switch contacts. If the coil circuit is open or the switch contacts are not making good contact, the relay should be replaced. The operator's manual typically provides a relay location diagram that shows the location and function of each relay in the electrical system. Keep a spare set of fuses and relays on hand to quickly replace any faulty components and keep your Kubota M135GX-III running smoothly.
Maintaining proper steering system alignment and responsiveness is critical for safe and efficient operation of your Kubota M135 GX-III. A misaligned or loose steering system can lead to increased tire wear, difficulty in controlling the tractor, and potentially dangerous situations, especially during high-speed road travel or when working on uneven terrain. Regular inspection and adjustment of the steering linkage are paramount to ensure optimal performance and prevent premature component failure. This section outlines the necessary procedures for inspecting and adjusting the steering components to ensure smooth and accurate steering. Remember, safety first! Always engage the parking brake, chock the wheels, and turn off the engine before performing any maintenance or adjustments on the steering system.
Begin by visually inspecting the entire steering linkage, from the steering wheel to the front wheels. Pay close attention to the tie rod ends, drag links, steering knuckles, and the steering gearbox itself. Look for signs of wear, such as excessive play, looseness, or damage to the rubber boots that protect the joints. Any significant play in the tie rod ends or drag links can indicate wear and necessitate replacement. Also, check for signs of leakage around the steering gearbox, which could indicate a failing seal. If any of these issues are present, address them before proceeding with the adjustment procedure; ignoring them will only lead to further problems. A thorough inspection is the foundation of effective maintenance.
To adjust the steering free play, locate the adjustment screw on the steering gearbox. Typically, this is a threaded bolt with a locknut that allows you to increase or decrease the tightness of the gears within the gearbox. Loosen the locknut and carefully turn the adjustment screw clockwise to reduce free play. It's crucial to make small adjustments and frequently check the steering wheel movement to avoid overtightening. Overtightening the screw can cause the gears to bind, leading to increased wear and difficulty in steering. Once you achieve the desired free play, tighten the locknut securely, ensuring the adjustment screw doesn't move. Finally, re-test the steering to confirm smooth and responsive operation.
The braking system is arguably the most critical safety component on your tractor. Regular inspection and maintenance of the brakes are essential to ensure reliable stopping power in all operating conditions. Neglecting brake maintenance can lead to reduced braking efficiency, increased stopping distances, and potentially catastrophic accidents. This section provides a comprehensive guide to inspecting and repairing the brake system on your Kubota M135 GX-III. Before working on the brake system, always ensure the engine is off, the parking brake is engaged, and the wheels are properly chocked for safety.
Begin by visually inspecting the brake pedals, linkages, and brake lines for any signs of damage, leaks, or wear. Ensure the brake pedals move freely and return to their fully released position when not depressed. Check the brake fluid reservoir level and top up as needed with the recommended brake fluid type. Inspect the brake lines for any cracks, bulges, or signs of corrosion, as these can compromise the integrity of the braking system. If you notice any leaks or damage to the brake lines, replace them immediately. Also, examine the brake shoes or pads for wear. Worn brake shoes or pads will reduce braking performance and require replacement.
To check the brake shoe or pad thickness, you may need to remove the brake drums or calipers, depending on the brake system design. Refer to the service manual for specific instructions on removing and inspecting these components. Measure the thickness of the brake shoes or pads using a vernier caliper and compare the measurement to the minimum thickness specified in the service manual. If the thickness is below the minimum specification, replace the brake shoes or pads. When replacing brake shoes or pads, always replace them in pairs to ensure even braking performance. Also, inspect the brake drums or rotors for any signs of wear, scoring, or damage.
After replacing the brake shoes or pads, it's essential to bleed the brake system to remove any air that may have entered the lines. Air in the brake lines can cause a spongy brake pedal feel and reduced braking performance. Refer to the service manual for the proper bleeding procedure, which typically involves opening the bleeder valve on each brake caliper or wheel cylinder while pumping the brake pedal. Continue bleeding until all air bubbles are removed from the fluid. After bleeding the brakes, test the braking performance to ensure proper operation.
The differential lock is a valuable feature that enhances traction in slippery or challenging terrain. It forces both rear wheels to rotate at the same speed, preventing one wheel from spinning freely while the other remains stationary. Regular inspection and maintenance of the differential lock mechanism are essential to ensure its proper function when needed. A malfunctioning differential lock can leave you stranded in muddy or icy conditions. Therefore, understanding its operation and performing routine checks are crucial.
First, familiarize yourself with the location and operation of the differential lock pedal or lever. Engage the differential lock and carefully observe the rear wheels. Both wheels should rotate at the same speed when the tractor is driven forward in a straight line on a loose surface like gravel or dirt. If one wheel continues to spin freely while the other remains stationary, the differential lock mechanism may be malfunctioning. This could be due to a worn or broken internal component, a stuck actuator, or a problem with the hydraulic or mechanical linkage.
Inspect the linkage connecting the differential lock pedal or lever to the differential housing. Look for any signs of damage, wear, or looseness. Ensure the linkage moves freely and that the actuator engages the differential lock mechanism fully when the pedal or lever is activated. If the linkage is damaged or worn, replace it to ensure proper engagement. You may also need to adjust the linkage to ensure it's properly aligned and functioning within the specified tolerances.
If the linkage is in good condition, the problem may lie within the differential housing itself. This could involve a worn or broken locking collar, a damaged actuator, or a problem with the internal gears. In such cases, it's best to consult a qualified mechanic or refer to the service manual for detailed instructions on disassembling and repairing the differential lock mechanism. Attempting to repair the differential lock without proper knowledge and tools can lead to further damage and costly repairs. After any repairs, thoroughly test the differential lock to ensure it engages and disengages smoothly and effectively.
Maintaining the front axle on your Kubota M135GX-III is critical for ensuring smooth operation, optimal traction, and preventing costly repairs down the line. Regular inspection is the first step. Carefully examine the axle housing for any signs of cracks, leaks, or damage from impacts. Pay close attention to the steering linkage and joints, looking for looseness or excessive play. A loose steering linkage can lead to wandering and reduced control, especially at higher speeds. Promptly address any issues you find to prevent further deterioration and potential safety hazards. Lubricating all grease fittings according to the manufacturer's recommendations is also paramount to its longevity and ability to perform the desired work with ease.
The front axle's lubrication system is vital for its performance and durability. Use the specified type of grease, as incorrect lubricants can cause damage. Before greasing, clean the fittings to prevent contaminants from entering the system. When applying grease, do so slowly and steadily, allowing the old grease to be forced out. Continue until fresh grease appears, indicating that the entire joint is properly lubricated. Don't over-grease, as this can damage the seals and cause grease to leak out, attracting dirt and debris, which will cause pre-mature wear. Periodic inspections of the axle oil level are also critical, addressing any leaks quickly to prevent fluid loss.
The rear axle is the workhorse of your Kubota M135GX-III, transferring power from the engine to the wheels. Therefore, proper rear axle service is essential for maintaining optimal performance and preventing costly breakdowns. Regular oil changes are paramount. Follow the recommended service intervals outlined in your owner's manual, and always use the specified type and grade of oil. A low fluid level and dirty fluid will cause premature damage to your machine. During the oil change, inspect the drain plug for metal particles, which can indicate internal wear. If you find an excessive amount of metal, further investigation may be needed to identify and address the source of the wear.
Beyond oil changes, the rear axle requires periodic inspection of its components. Check the axle housing for any signs of leaks or damage. Inspect the wheel bearings for play or roughness. A failing wheel bearing can cause excessive heat, noise, and eventually lead to complete failure. If you notice any issues, replace the bearings promptly to prevent further damage. Furthermore, ensure that all bolts and fasteners are tightened to the proper torque specifications. Loose fasteners can lead to vibration and premature wear of the components. Taking these proactive steps will help ensure the long-term reliability of your rear axle.
The wheels and tires on your Kubota M135GX-III are more than just rolling components; they play a crucial role in traction, stability, and overall performance. Understanding the proper wheel and tire specifications is essential for safe and efficient operation. Refer to your owner's manual for the recommended tire sizes and pressures for both front and rear tires. Using the wrong size tires can affect the tractor's handling and stability. Maintaining the correct tire pressure is equally important. Underinflated tires can lead to excessive wear and reduced fuel economy, while overinflated tires can result in a rough ride and reduced traction. Check tire pressure regularly, especially before and after heavy use.
Wheel and tire maintenance extends beyond just inflation. Inspect the tires regularly for signs of wear, damage, or cracking. Replace worn or damaged tires promptly to maintain proper traction and prevent blowouts. Check the wheel lug nuts for tightness, tightening them to the specified torque if necessary. Loose lug nuts can cause the wheels to wobble or even come loose, leading to a serious accident. Additionally, ensure that the wheels are properly aligned to prevent uneven tire wear. If you notice any unusual wear patterns, have the alignment checked and adjusted by a qualified technician. These simple steps can significantly extend the life of your tires and ensure safe operation.
Removing and installing the cab on a Kubota M135GX-III requires careful planning and execution. Before starting any work, disconnect the battery to prevent electrical hazards. Consult the service manual for the specific steps and torque specifications for your model. Start by disconnecting all electrical connections to the cab, carefully labeling each one to ensure proper reconnection during reinstallation. Then, disconnect any hydraulic lines or hoses that run to the cab, taking precautions to prevent fluid spills. Using appropriate lifting equipment, carefully lift the cab away from the tractor chassis.
During installation, ensure that the cab is properly aligned with the chassis before lowering it into place. Reconnect all electrical connections and hydraulic lines, making sure they are securely fastened and leak-free. Tighten all bolts and fasteners to the specified torque, following the sequence outlined in the service manual. Once the cab is installed, test all functions, including the lights, wipers, and air conditioning, to ensure they are working properly. If you encounter any difficulties or are unsure about any step of the process, consult a qualified technician for assistance. Improper cab removal or installation can lead to damage to the tractor or cab, as well as potential safety hazards.