The Case 850B is a powerful crawler dozer used in a variety of heavy construction and earthmoving tasks. Like many large pieces of machinery, its performance relies heavily on its hydraulic system to operate key functions such as lifting, pushing, and tilting. When the hydraulics on a Case 850B fail or exhibit a loss of power, it can lead to significant delays and costly downtime. Understanding the common causes of hydraulic failure and how to troubleshoot the issue is crucial for keeping the dozer running efficiently. This article provides a detailed guide on diagnosing and solving hydraulic problems in the Case 850B.
Understanding the Case 850B and Its Hydraulic System
The Case 850B is part of the Case series of crawler dozers, which are designed for tasks such as grading, excavation, and land clearing. The 850B model is particularly known for its strong pushing power, robust design, and excellent performance in tough terrains. Its hydraulic system is essential to its operation, providing power to components like the blade, tracks, and steering system. The hydraulic system includes a pump, hydraulic fluid, valves, cylinders, and hoses that work in unison to move the machine's parts.
The hydraulic system in the Case 850B is powered by a hydraulic pump, which is typically driven by the engine. This pump circulates hydraulic fluid through a series of valves, lines, and actuators that perform tasks like lifting and tilting the blade or driving the tracks. A loss of hydraulic power can result from various issues within the hydraulic system, including low fluid levels, pump failure, valve malfunctions, or clogged filters.
Common Causes of Hydraulic Failure in the Case 850B

1. Low Hydraulic Fluid Levels
   • One of the most common reasons for a loss of hydraulic power is low fluid levels. Hydraulic fluid is essential for transferring power and maintaining the system's pressure. If the fluid is low, the pump cannot generate enough pressure to perform the necessary operations.
     
   • Cause: Leaks in the hydraulic lines, seals, or cylinders can cause gradual fluid loss. Over time, if fluid is not replenished, the system will fail to function properly.
     
2. Contaminated Hydraulic Fluid
   • Hydraulic systems are sensitive to contaminants, including dirt, debris, and moisture. If these contaminants enter the fluid, they can cause wear on the system’s internal components, clog filters, and cause erratic behavior in the hydraulics.
     
   • Cause: Contamination can occur through poor maintenance practices, failure to change filters regularly, or damage to seals or hoses that allow external particles to enter the system.
     
3. Faulty Hydraulic Pump
   • The hydraulic pump is the heart of the system, responsible for generating the pressure required for the hydraulic functions. If the pump begins to fail, it can result in a loss of power or erratic performance in the hydraulic system.
     
   • Cause: Overheating, wear, or contamination can cause the pump to fail. In some cases, a worn-out or damaged pump may not be able to generate enough pressure to drive the hydraulic cylinders and valves.
     
4. Hydraulic Valve Malfunctions
   • The hydraulic control valves direct the flow of fluid to various parts of the dozer. A malfunctioning valve can cause hydraulic failure by preventing fluid from reaching the proper areas or by causing an imbalance in the system’s pressure.
     
   • Cause: A valve may become stuck, blocked, or worn out over time, leading to improper fluid distribution and loss of hydraulic power.
     
5. Clogged Hydraulic Filters
   • The filters in the hydraulic system are designed to remove contaminants from the fluid before it circulates through the components. If the filters become clogged, it can restrict fluid flow, leading to a loss of hydraulic pressure and poor performance.
     
   • Cause: Failure to regularly check and replace the hydraulic filters can lead to clogging. Additionally, contamination from external sources can contribute to faster filter wear.
     
6. Damaged Hydraulic Hoses or Leaks
   • Hydraulic hoses are used to transport fluid under high pressure throughout the system. If a hose becomes damaged or develops a leak, it can result in a loss of fluid and reduced hydraulic pressure.
     
   • Cause: Hose wear and tear, exposure to extreme temperatures, or physical damage from debris can all lead to leaks or ruptures in the hoses.
     

1. Check Fluid Levels
   • The first step is to check the hydraulic fluid levels. Low fluid is one of the most common causes of hydraulic loss. If the fluid is low, top it off with the recommended fluid type.
     
   • Action: If the fluid is low, check for visible leaks around the system. If you notice a drop in fluid levels over time, inspect hoses, cylinders, and seals for leaks.
     
2. Inspect the Fluid for Contaminants
   • Examine the hydraulic fluid for any signs of contamination. If the fluid is dirty or appears to have metal shavings or particles floating in it, the system is likely experiencing internal wear.
     
   • Action: Drain and replace the contaminated fluid, and replace the filters. Clean or replace the components that may have been damaged by contamination, such as pumps or valves.
     
3. Test the Hydraulic Pump
   • If the fluid is clean and at the proper level, but the hydraulics still aren’t functioning, the next step is to test the hydraulic pump. A weak or failing pump may not generate enough pressure for the system to operate effectively.
     
   • Action: Check the pump’s output pressure using a hydraulic pressure gauge. If the pressure is too low, the pump may need to be repaired or replaced.
     
4. Examine Hydraulic Control Valves
   • If the pump appears to be working correctly, but the hydraulics are still malfunctioning, inspect the control valves. A stuck or blocked valve could be preventing the proper flow of hydraulic fluid.
     
   • Action: Test the valves by operating the machine in various modes. If one valve does not respond as expected, clean or replace the valve. In some cases, the valve’s seals may need to be replaced to restore functionality.
     
5. Check the Hydraulic Filters
   • Inspect the hydraulic filters for signs of clogging or wear. A clogged filter will prevent fluid from circulating properly, reducing the system's overall efficiency.
     
   • Action: Replace any clogged or dirty filters, and make sure to use the proper type of filter recommended by the manufacturer.
     
6. Inspect the Hydraulic Hoses and Fittings
   • Check all hydraulic hoses for signs of damage or wear. A ruptured or leaking hose can cause fluid loss and hydraulic failure. Look for areas where the hoses may be rubbing against other surfaces or exposed to excessive heat.
     
   • Action: Replace any damaged hoses or fittings, and ensure that all connections are tight and leak-free. It’s also advisable to check for any potential sources of friction that could cause future damage to the hoses.
     

1. Routine Fluid Checks: Regularly check hydraulic fluid levels and inspect for contamination. Replace fluid as recommended in the owner's manual to maintain system performance.
   
2. Scheduled Filter Replacements: Replace hydraulic filters at the intervals recommended by the manufacturer. This will help prevent contaminants from damaging the system.
   
3. Inspect Hoses and Seals: Periodically inspect all hydraulic hoses and seals for wear, leaks, or signs of damage. Address any issues promptly to prevent fluid loss.
   
4. Monitor Pump Performance: Keep an eye on the performance of the hydraulic pump. If you notice any decrease in pressure or efficiency, investigate the cause before it leads to a full pump failure.
   
5. Clean System Components: Regularly clean the hydraulic system components to prevent contamination. This includes cleaning the hydraulic tank, valve assemblies, and pump.
   

The Legacy of the D9 18A Series
The Caterpillar D9 18A is a classic track-type tractor introduced in the late 1950s, part of the early evolution of the D9 series. Known for its raw mechanical power and durability, the 18A variant was powered by the CAT D353 engine—a robust inline six-cylinder diesel with precombustion chamber ignition. These machines were widely used in mining, road building, and land clearing, and many are still operational today due to their simple mechanical systems and rebuildable components.
Coolant in Oil Symptoms and Initial Assessment
One of the most concerning issues in older diesel engines like the D353 is the presence of coolant in the engine oil. This condition often presents as milky oil in the pan, rising oil levels, or unexplained coolant loss. In the case of the D9 18A, the machine had been parked for several years after the owner noticed water entering the crankcase. The coolant was drained and replaced with water during use, which eventually revealed the leak more clearly.
Common Leak Sources in D353 Engines
Before assuming a liner seal failure, several components should be inspected:

• Oil Cooler: A frequent culprit in older CAT engines. Internal corrosion or seal failure can allow coolant to mix with oil. This is especially common in machines that sit unused or have poor coolant maintenance.
  
• Water Pump: Gear-driven and mounted low, a failed seal can allow coolant to enter the timing case or oil passages.
  
• Cylinder Liners and O-Rings: While not as common in CAT engines as in some others, deteriorated liner seals or pinholed liners can cause coolant intrusion. This is more likely in engines with neglected coolant systems or high hours.
  

• Hydraulic Jacking from Below: Effective for front cylinders but difficult for rear ones due to the hard bar obstruction.
  
• Top-Pulling Tools: Using a properly sized puller that grips the liner bore without scoring the walls. Homemade tools may work but risk damaging the liner or block.
  

• Pitting
  
• Cracks
  
• Seal groove erosion
  

• Pressure test the oil cooler
  
• Inspect water pump seals and housing
  
• Check for external leaks or signs of coolant loss
  

Operating heavy machinery, such as skid steers or other construction vehicles, often involves working in challenging conditions, including mud, soft soil, snow, or uneven terrain. One common issue that operators face is getting their equipment stuck. Whether it's in soft ground, on a steep incline, or buried under debris, getting stuck is not only frustrating but can also lead to costly delays and potential damage to the machine. This article provides an in-depth look at what to do when your skid steer or other construction equipment becomes stuck, with detailed solutions and preventive measures.
Understanding Why Equipment Gets Stuck
Before jumping into how to resolve the issue, it's important to understand why construction equipment like skid steers get stuck in the first place. There are several contributing factors:

1. Soft Ground Conditions
   Wet, muddy, or sandy conditions are among the most common reasons that heavy machinery becomes immobilized. The weight of the equipment causes it to sink into the soft ground, leading to the wheels or tracks becoming bogged down.
   
2. Improper Ground Preparation
   Lack of ground preparation, such as insufficient grading or improperly compacted surfaces, can cause equipment to get stuck. This is especially true for machines working in newly excavated or unprepared areas.
   
3. Equipment Overload or Improper Weight Distribution
   Overloading the machine with more material than it’s rated to handle or poorly distributing the weight can cause the vehicle to become stuck. For example, trying to carry a load too heavy for the skid steer can cause it to lose traction, especially if the load is unevenly distributed.
   
4. Obstructions and Debris
   Sometimes, machinery can get stuck due to large obstructions such as rocks, tree roots, or large debris. These obstacles can block movement, especially if they are lodged under the machine or in its path.
   
5. Mechanical Failures
   If the equipment’s hydraulic or drive systems fail, the machine can become stuck, even on relatively stable ground. Mechanical failures, such as broken axles, malfunctioning transmissions, or failing tracks, can prevent the machine from moving.
   

1. Assess the Situation
   • Evaluate the Terrain: Look for signs that the equipment is stuck due to soft ground or debris. Check the condition of the surrounding area and identify any potential hazards that could make the situation worse.
     
   • Check the Load: If the machine is carrying a load, ensure it is not excessively heavy or unevenly distributed. Uneven loads can make the situation worse by shifting the center of gravity.
     
   • Inspect for Obstructions: Look underneath or around the machine for large objects like rocks, logs, or tree roots that could be hindering movement.
     
2. Disengage the Drive
   • If the equipment has become stuck while operating, disengage the drive and stop all movements. Continuing to try and move the vehicle while it’s stuck can cause damage to the drivetrain or hydraulic system.
     
   • Engage the parking brake if the machine is on an incline, to prevent further movement.
     
3. Clear the Area
   • Remove Obstacles: If there are large objects or debris in the way, remove them carefully. Use an auxiliary tool, such as a bucket or grapple, to move rocks or debris that are obstructing the equipment.
     
   • Loosen the Soil: In cases of soft or muddy ground, use a digging attachment or a shovel to loosen the soil around the wheels or tracks. Loosening the ground can provide the equipment with a bit more traction to help free it.
     
4. Use the Right Tools
   • Traction Mats: One of the quickest ways to free stuck equipment is to use traction mats. These mats, often made from durable materials like rubber or metal, can be placed under the wheels or tracks to help provide extra grip on slippery or muddy surfaces.
     
   • Chains or Tow Straps: If another vehicle is available, use chains or heavy-duty tow straps to attempt to pull the stuck equipment out. Be sure to attach the chains or straps to solid tow points on both the stuck machine and the recovery vehicle.
     
   • Winch: If you have a winch system available, use it to pull the equipment out of the stuck position. A winch can be attached to a stationary object like a tree or another vehicle, providing enough force to get the machine unstuck.
     
5. Adjust the Machine’s Position
   • Rocking the Equipment: Gently rocking the equipment back and forth can help free the wheels or tracks from the soft ground. This method works best on machines with wheels or tracks that are not deeply sunk. Engage the forward and reverse gears alternately to create a rocking motion, but do so carefully to avoid damaging the transmission.
     
   • Use of a Jockey Wheel: If available, use a jockey wheel or dolly to adjust the position of the machine. This is particularly useful if the machine is stuck in a narrow or confined space.
     
6. Try to Create Traction
   • Add Material: If the machine is stuck on soft or muddy ground, adding material to improve traction can be a helpful solution. Sand, gravel, or even wood chips can be spread under the wheels or tracks to provide extra grip. This is particularly effective if the machine is stuck in a very soft surface.
     
   • Deflate the Tires: For wheeled equipment, slightly deflating the tires can increase their surface area, helping them gain traction in soft ground. Be careful not to deflate the tires too much, as this can cause damage.
     
7. Consider External Help
   • Call for a Tow Truck: If the equipment is severely stuck and cannot be freed with on-site methods, it may be necessary to call for professional help. A tow truck or heavy recovery vehicle can pull the stuck machine out safely.
     
   • Use a Crane: In some cases, a crane may be required to lift the equipment out of a difficult situation, especially when the machine is stuck in deep or uneven terrain.
     

1. Proper Ground Preparation
   • Prior to operating equipment in an area, ensure the ground is prepared and stable enough to support the weight of the machine. Avoid working in areas that are too soft, muddy, or uneven without proper groundwork.
     
2. Know Your Equipment's Limits
   • Familiarize yourself with the operating limits of your equipment, including its weight capacity, maximum load, and terrain suitability. Pushing the equipment beyond these limits can increase the likelihood of getting stuck.
     
3. Check Weather Conditions
   • Always check the weather forecast before operating in areas prone to rain or snow. Wet conditions can quickly turn otherwise stable ground into soft, sticky mud.
     
4. Use the Right Attachments
   • Choose the correct attachments for the job at hand. Using an inappropriate attachment, like a heavy bucket on soft soil, can overload the machine and make it more prone to getting stuck.
     
5. Maintain the Equipment
   • Regular maintenance is key to preventing mechanical issues that can contribute to getting stuck. Ensure the tires or tracks are in good condition and that the hydraulic and drive systems are functioning properly.
     

The Mitsubishi ME-20 is a versatile and compact electric forklift designed to meet the needs of light to medium-duty material handling in warehouses, distribution centers, and manufacturing plants. Known for its energy efficiency and maneuverability, the ME-20 is often chosen for applications that require lifting and transporting goods in tight spaces. This article will explore the features, maintenance tips, and common issues associated with the Mitsubishi ME-20 forklift, providing operators and fleet managers with valuable insights for maintaining the machine's performance.
Overview of Mitsubishi's ME-20 Forklift
Mitsubishi Heavy Industries, a major player in the global manufacturing industry, has produced a wide range of equipment, including forklifts. The Mitsubishi ME-20 is part of their electric forklift lineup, designed for environments where low emissions, reduced noise, and lower operational costs are key considerations. Electric forklifts like the ME-20 are particularly well-suited for indoor use, as they do not produce exhaust fumes and require less maintenance compared to their internal combustion counterparts.
The ME-20 is equipped with a 2,000 kg (about 4,400 lbs) lifting capacity and offers a lift height of up to 4.5 meters (about 14.8 feet), making it ideal for stacking goods in narrow aisles. Its electric motor allows for smooth, quiet operation, which is an advantage in indoor settings. With its ability to work in confined spaces and handle a wide range of materials, the ME-20 provides an efficient solution for various industries, including retail, logistics, and manufacturing.
Key Features of the Mitsubishi ME-20 Forklift

1. Electric Power System
   • The ME-20 is powered by an electric motor that is driven by a battery. The electric system provides several advantages, such as quieter operation, zero emissions, and lower operating costs compared to diesel or LPG forklifts.
     
   • The forklift’s battery is typically a 24V unit, offering enough power for a full shift of operations before needing a recharge.
     
2. Maneuverability
   • One of the standout features of the ME-20 is its compact design, which makes it exceptionally easy to maneuver in tight spaces. The forklift’s small turning radius allows it to operate efficiently in narrow aisles and crowded environments.
     
3. Lift Capacity and Reach
   • With a lifting capacity of 2,000 kg, the ME-20 is suitable for light to moderate loads. The lifting height can reach up to 4.5 meters, allowing operators to handle pallets and goods at a height typically found in warehouse racking systems.
     
4. Ergonomics and Operator Comfort
   • The ME-20 is designed with operator comfort in mind. It features a spacious operator compartment with easy-to-reach controls and a comfortable seat, which is crucial for long shifts. Additionally, the controls are responsive, which helps in reducing operator fatigue during daily use.
     
5. Battery Management System
   • The forklift is equipped with a battery management system that monitors battery health and ensures it operates at peak efficiency. The system helps to extend battery life by preventing overcharging and deep discharging, thus improving the overall performance and longevity of the forklift.
     

1. Battery Maintenance
   • Battery Charging: Ensure that the battery is charged properly and regularly. Overcharging or undercharging can reduce battery life. It is important to follow the manufacturer’s guidelines for charging intervals and avoid running the battery down completely before recharging.
     
   • Battery Cleaning: Keep the battery terminals clean and free of corrosion. Corrosion can hinder electrical contact and lead to starting issues. Use a clean, dry cloth to wipe the terminals and check for any buildup of dirt or grime.
     
   • Battery Watering: If the forklift uses a lead-acid battery, check the water levels in the battery cells regularly. Top up with distilled water as needed to prevent the battery from drying out, which can affect its performance.
     
2. Tire and Wheel Checks
   • The tires on an electric forklift like the ME-20 should be regularly inspected for signs of wear or damage. Over time, the tires can wear down, especially if the forklift is frequently used on rough or uneven surfaces.
     
   • Check the tires for flat spots, cuts, or punctures. Worn-out tires can affect the forklift’s stability and maneuverability. If you notice any issues, replace the tires to avoid safety risks.
     
3. Hydraulic System Maintenance
   • The hydraulic system of the ME-20 controls the lifting and tilting of the forks. Regularly check the hydraulic fluid levels to ensure smooth operation. Low hydraulic fluid can result in sluggish or uneven lifting, which can impact productivity.
     
   • Inspect hydraulic hoses and connections for leaks or damage. If you notice any leaks, replace the faulty components immediately to avoid further damage to the hydraulic system.
     
4. Brake System Maintenance
   • The ME-20 uses a hydraulic brake system, which should be checked regularly for any signs of wear or fluid leaks. Inspect the brake pads for thickness and replace them if they are worn down. The brake fluid should also be checked and replaced periodically to ensure the system operates effectively.
     
   • If the forklift pulls to one side or if the brakes feel soft, it could indicate an issue with the brake system that needs immediate attention.
     
5. Electrical System and Wiring
   • As an electric forklift, the ME-20 relies heavily on its electrical system to power the motor and other components. Check all electrical wiring for signs of wear or damage. Over time, wires may become frayed or exposed, leading to short circuits or other electrical issues.
     
   • The controller and wiring should also be inspected for faults or signs of overheating. Any issues with the controller can lead to erratic behavior or a complete failure to operate, requiring immediate attention from a trained technician.
     
6. Lift Mechanism Inspection
   • Inspect the lift cylinders and chains regularly to ensure smooth and reliable lifting. If you notice any unusual noises, such as squeaking or grinding, it could indicate a lack of lubrication or worn components. Lubricate the lift mechanism as recommended in the operator’s manual.
     
   • Check the forks for any signs of wear or bending, especially if they are used frequently for heavy lifting. Worn-out forks can affect load stability and cause safety hazards.
     

1. Forklift Won’t Start
   • If the forklift fails to start, the first thing to check is the battery. Ensure the battery is fully charged and the connections are secure. If the battery is fine, check the electrical system for issues such as blown fuses or damaged wiring.
     
   • If the forklift still won’t start, it may be due to a faulty controller or motor. In such cases, consult the service manual and contact a qualified technician for a more in-depth diagnosis.
     
2. Forklift Lifts Slowly
   • Slow lifting could be caused by low hydraulic fluid levels, worn-out seals, or a problem with the hydraulic pump. Check the fluid levels and replace any worn-out seals or damaged hoses. If the issue persists, inspect the hydraulic pump for faults.
     
3. Uneven or Jerky Movement
   • Jerky movements may be caused by issues in the electric drive motor or the hydraulic system. Check the motor for signs of wear or overheating, and ensure the hydraulic system is properly lubricated and functioning.
     
4. Brakes Not Engaging Properly
   • If the brakes are not engaging properly, check the brake fluid levels and inspect the brake pads. Low brake fluid or worn-out pads can cause poor braking performance. If the issue persists, check the hydraulic lines for leaks or damage.
     

The CAT 613 Scraper and Its Hydraulic Brake Architecture
The Caterpillar 613 motor scraper is a mid-size self-loading earthmoving machine designed for high-speed hauling and efficient cut-and-fill operations. Introduced in the 1970s and refined through several generations, the 613 series became a staple in highway construction and site development. With a bowl capacity of approximately 11 cubic yards and a top speed exceeding 25 mph, the 613 was engineered for productivity and maneuverability.
Its braking system is a combination of service brakes, secondary brakes, and a hydraulic park brake. These systems are interlinked through a series of valves and accumulators, making their operation dependent on hydraulic pressure and valve sequencing.
Understanding the Park Brake and Secondary Brake Relationship
The park brake on the CAT 613 is hydraulically released and spring-applied. This means that when hydraulic pressure is lost, the brake engages automatically—a safety feature designed to prevent rollaway incidents. The secondary brake system serves as a backup to the service brakes and shares hydraulic components with the park brake.
A common point of confusion is whether the park brake release valve can operate independently of the secondary brake valve. In most configurations, the answer is no. The secondary brake valve must be released first to allow hydraulic pressure to reach the park brake release circuit. This sequencing ensures that the machine cannot be moved unless both braking systems are confirmed to be disengaged under controlled conditions.
Key Components and Terminology

• Park Brake Valve: Controls hydraulic flow to release the spring-applied park brake.
  
• Secondary Brake Valve: Manages backup braking and often acts as a gatekeeper for park brake release.
  
• Accumulator: Stores hydraulic pressure to maintain brake release during engine shutdown or low RPM.
  
• Hydraulic Interlock: Prevents unintended brake release unless specific conditions are met.
  

• Check hydraulic pressure at the accumulator and verify charge level
  
• Inspect the secondary brake valve for proper function and leaks
  
• Confirm that the park brake valve receives signal and pressure after secondary valve activation
  
• Test solenoids and electrical inputs if valves are electronically actuated
  
• Examine return springs and mechanical linkages for binding or wear
  

• Replace hydraulic filters every 500 hours to prevent contamination
  
• Test accumulator pressure monthly and recharge as needed
  
• Train operators to avoid abrupt shutdowns that may trap pressure in the wrong circuit
  
• Use OEM brake fluid and seals to maintain compatibility and longevity
  

The Case 1840 skid steer is a reliable piece of equipment widely used in construction, landscaping, and other industries requiring compact yet powerful machinery. However, like all machinery, it can encounter issues that prevent it from starting. One common issue reported by operators is when the machine turns over but does not start. This problem can be caused by several factors ranging from electrical to fuel system issues.
This article provides a comprehensive troubleshooting guide for diagnosing and resolving the "turns but won't start" issue on a Case 1840 skid steer. By breaking down the potential causes, solutions, and preventive measures, operators can quickly identify the root cause of the problem and take the necessary steps to get the machine running again.
Overview of the Case 1840 Skid Steer
Manufactured by Case Construction, the 1840 skid steer loader is known for its compact size, versatility, and power. With a lift capacity of approximately 1,600 pounds and a range of attachments, the Case 1840 is ideal for tasks such as digging, grading, and material handling. The machine is powered by a diesel engine, which drives both its hydraulic system and the drivetrain.
Despite its robust design, like any mechanical system, the Case 1840 can experience operational issues over time. One of the most frustrating problems is when the engine turns over but fails to start, indicating an underlying issue that needs to be addressed.
Common Causes of "Turns But Won't Start" Issue

1. Fuel System Issues
   One of the most common reasons why a skid steer may turn over but not start is a problem with the fuel system. Diesel engines require proper fuel delivery and air-fuel mixture to start and run correctly. If there is any issue with fuel flow, the engine will not start, even if the starter motor is functioning.
   • Fuel Filter Clogs: A clogged fuel filter can prevent the proper flow of diesel to the engine. Over time, debris and contaminants can build up in the filter, restricting fuel flow. If the fuel filter is clogged, it should be replaced according to the manufacturer’s recommendations.
     
   • Fuel Lines Blockage or Leaks: Check the fuel lines for any signs of blockage or leaks. If the fuel is not reaching the engine, or if air is getting into the lines, the engine won’t start. Inspect the fuel lines carefully and replace any damaged or leaking hoses.
     
   • Air in the Fuel System: Air in the fuel system can cause the engine to turn over but not start. If air has entered the fuel lines, it can prevent proper fuel injection. To fix this, the fuel system may need to be primed by using the bleed valve on the fuel filter or injection pump.
     
2. Electrical System Problems
   The electrical system in the Case 1840 plays a crucial role in starting the engine and powering critical components. Issues with the battery, starter motor, or ignition system can prevent the engine from starting.
   • Battery Voltage and Condition: Even if the engine turns over, a weak or partially discharged battery may not provide enough power to start the engine. Ensure that the battery is fully charged, and check the terminals for corrosion. Clean any corrosion and ensure the connections are tight.
     
   • Starter Motor: The starter motor is responsible for cranking the engine. If the starter motor is faulty or worn, it may turn over but fail to engage the engine properly. Testing the starter motor and its solenoid can help identify if this is the issue.
     
   • Ignition Switch and Wiring: The ignition system and its associated wiring could also be at fault. If the ignition switch is malfunctioning, it may not send the correct signals to the starter motor or other essential systems. Inspect the wiring for any signs of wear or damage that could disrupt the electrical flow.
     
3. Glow Plug Malfunctions (Cold Start Issues)
   Diesel engines, particularly in colder weather, rely on glow plugs to preheat the combustion chamber for smooth engine start-up. If the glow plugs are not functioning correctly, the engine may turn over but fail to start, especially in cold conditions.
   • Glow Plug Failure: If one or more glow plugs fail, it can make it harder for the engine to start, as it will not heat the fuel-air mixture enough for combustion. Test the glow plugs using a multimeter to ensure they are working properly. If necessary, replace the faulty glow plugs.
     
   • Glow Plug Relay Issues: The glow plug relay controls the timing of the glow plug operation. If the relay is faulty, it may fail to provide power to the glow plugs when needed, leading to starting issues.
     
4. Fuel Injector Problems
   Fuel injectors are responsible for delivering the right amount of fuel into the combustion chamber for ignition. If the injectors are clogged or malfunctioning, the engine may turn over but fail to start because the proper air-fuel mixture is not being provided.
   • Clogged or Dirty Injectors: Over time, injectors can become clogged with carbon or other debris. This reduces the amount of fuel delivered to the engine, making it difficult for the engine to start. Cleaning or replacing the injectors may resolve the issue.
     
   • Injector Pump Issues: The injector pump controls the flow and timing of fuel injected into the engine. If the injector pump is malfunctioning, it can prevent the injectors from delivering fuel at the correct time. A faulty pump may need to be replaced.
     
5. Fuel Quality
   Poor-quality fuel or contaminated fuel can also cause starting issues. Diesel fuel that is old or has water contamination may not ignite properly, even if the engine turns over.
   • Water in Fuel: If water has entered the fuel tank, it can cause starting problems, as diesel engines rely on a consistent fuel-air mixture. Water can prevent proper combustion, especially during cold starts. Drain the fuel tank and replace any contaminated fuel with fresh, clean diesel.
     
   • Old or Gelled Diesel: In cold weather, diesel fuel can gel and become thick, preventing it from flowing properly. If this is the case, it may be necessary to add fuel additives to restore proper fuel flow or even warm up the fuel tank in extreme cases.
     
6. Faulty Sensors or ECU Malfunctions
   Modern machines like the Case 1840 often have electronic control units (ECUs) that monitor various components, including sensors for fuel pressure, engine temperature, and air intake. A malfunctioning sensor or faulty ECU can prevent the engine from starting, even though it turns over.
   • Crankshaft Position Sensor: The crankshaft position sensor provides data to the ECU to determine the timing of fuel injection and ignition. If this sensor is malfunctioning, it can prevent the engine from starting.
     
   • Other Sensors: Other sensors, such as the fuel pressure sensor or the camshaft position sensor, can also cause starting issues if they fail. These sensors provide critical information to the ECU, which controls fuel delivery and ignition timing.
     

1. Check the Battery: Start by checking the battery voltage and condition. If the voltage is low, recharge or replace the battery. Clean the terminals and ensure all connections are secure.
   
2. Inspect Fuel System: Check the fuel filter, fuel lines, and fuel injectors for any clogs or leaks. Replace the fuel filter if necessary, and prime the fuel system to eliminate any air in the lines.
   
3. Test Glow Plugs: In cold weather, ensure that the glow plugs are functioning properly by testing them with a multimeter. Replace any faulty glow plugs or glow plug relays.
   
4. Inspect Electrical System: Examine the wiring and ignition switch for any signs of wear or damage. Test the starter motor to ensure it is functioning correctly.
   
5. Check for Fuel Contamination: Drain the fuel tank if you suspect water or contaminated fuel. Replace with fresh, clean diesel and add fuel additives if necessary to prevent gelling.
   
6. Consult the Service Manual: Always refer to the Case 1840 service manual for specific troubleshooting steps, wiring diagrams, and diagnostic procedures to ensure accurate diagnosis and repair.
   

Track Chain Design and Initial Stiffness
When installing new track groups—especially SALT (Sealed and Lubricated Track) chains—on a dozer like the Caterpillar D7F, it's common to observe stiffness in the links and a lack of sag across the top of the track. This is not a defect but a result of how new chains are manufactured and assembled. SALT chains are press-fit and sealed with internal lubrication, which makes the pin and bushing joints tight until they wear in through use.
The stiffness is most noticeable during the first few hours of operation. The track links may appear rigid, and the machine may feel smoother due to reduced vibration from worn components. This is expected behavior and part of the break-in process.
What Is SALT and Why It Matters
SALT chains are designed to extend undercarriage life by sealing lubricant inside each joint. This reduces internal wear and prevents contamination from dirt and moisture. Key features include:

• Press-fit pins and bushings
  
• Internal grease or oil sealed with elastomer rings
  
• Reduced maintenance compared to dry chains
  
• Longer service intervals
  

• Laying out the chain on a flat surface
  
• Using impact force to settle the links
  
• Bolting pads with torque specs between 250–300 ft-lbs
  

• Monitor for hot pins or uneven wear
  
• Check for abnormal noise or vibration
  
• Observe track sag and adjust tension if necessary
  

• One side loosens significantly faster than the other
  
• Pins show discoloration or heat marks
  
• Track links bind or skip during rotation
  
• Audible popping or grinding noises
  

• Recheck track tension after 10–20 hours of use
  
• Inspect pad bolts for torque loss
  
• Grease idlers and rollers regularly
  
• Avoid high-speed travel during break-in
  
• Keep the undercarriage clean to prevent abrasive wear
  

The Kobelco RK70M is a well-known model in the range of Kobelco crawler cranes, a Japanese brand recognized for manufacturing heavy machinery that is used in the construction, mining, and infrastructure sectors. The RK70M is a versatile and durable crane, designed to handle a variety of lifting and hoisting tasks with efficiency and precision. Like all heavy machinery, proper maintenance is essential to ensure the longevity, safety, and performance of the crane.
This article provides a comprehensive overview of the service and maintenance procedures for the Kobelco RK70M, highlighting key components, common issues, and tips for effective upkeep. Whether you're an operator, a mechanic, or a fleet manager, understanding the maintenance requirements of the RK70M is crucial for minimizing downtime and extending the lifespan of the crane.
Overview of the Kobelco RK70M Crawler Crane
Kobelco, founded in 1930, is one of the leading manufacturers of hydraulic cranes, excavators, and other heavy construction equipment. Over the years, the company has built a reputation for reliability, efficiency, and cutting-edge technology. The Kobelco RK70M is part of the company's crawler crane lineup, known for its impressive lifting capacity, stability, and versatility in various operational environments.
The RK70M is designed to handle a maximum lifting capacity of up to 70 tons, making it suitable for a wide range of construction applications, such as steel erection, roadwork, and heavy equipment transport. It features a strong and stable undercarriage, an advanced hydraulic system, and a user-friendly control system that allows operators to perform complex lifting tasks with ease.
Service and Maintenance Needs for the Kobelco RK70M
Like any piece of heavy machinery, the Kobelco RK70M requires regular service and maintenance to ensure its optimal performance. Neglecting regular maintenance can lead to premature wear, costly repairs, and potentially hazardous situations on the job site.
The service manual for the Kobelco RK70M provides a comprehensive set of guidelines for routine maintenance, troubleshooting, and repairs. Here are some of the essential areas of focus:

1. Engine Maintenance
   The engine is the heart of the RK70M, providing the necessary power to operate the hydraulic systems and perform lifting operations. Regular engine maintenance is critical for avoiding breakdowns and ensuring fuel efficiency.
   • Oil and Filter Changes: Engine oil should be changed at regular intervals to maintain engine health. The frequency of oil changes depends on the operating conditions, but it is generally recommended to change the oil every 250 hours of operation. Oil filters should also be replaced during each oil change to ensure proper filtration and engine protection.
     
   • Cooling System Checks: The engine’s cooling system plays a vital role in preventing overheating. Check the coolant levels regularly, and ensure that the radiator and hoses are free from leaks or blockages. Overheating can cause significant engine damage and lead to costly repairs.
     
   • Air Filter Maintenance: A clean air filter is essential for optimal engine performance. Air filters should be checked frequently and replaced when they show signs of dirt accumulation. Clogged air filters can restrict airflow to the engine, leading to reduced power output and increased fuel consumption.
     
2. Hydraulic System Maintenance
   The hydraulic system is responsible for powering the crane's boom and other lifting components. Given the complexity and importance of the hydraulic system, it requires regular checks and maintenance to avoid performance issues.
   • Hydraulic Fluid Checks: Hydraulic fluid should be checked regularly for contamination and proper levels. Low fluid levels or dirty fluid can lead to erratic crane movements, poor lifting performance, or complete hydraulic system failure. It is crucial to use the correct type of hydraulic fluid as specified in the service manual to avoid damaging the system.
     
   • Hydraulic Filter Replacement: Just like the engine, the hydraulic system has filters that need to be replaced periodically. The filters prevent debris from entering the system and causing damage to the hydraulic components.
     
   • Hoses and Fittings Inspection: Inspect the hydraulic hoses for wear, cracks, or leaks. If any issues are found, hoses should be replaced immediately to prevent fluid loss or contamination. Tightening fittings and checking for leaks is also essential to maintaining proper hydraulic pressure.
     
3. Track and Undercarriage Maintenance
   The undercarriage of the RK70M, including its tracks, rollers, and sprockets, plays a critical role in ensuring the crane's stability and mobility. Proper maintenance of the undercarriage components helps prevent uneven wear and improves the crane's maneuverability on rough terrain.
   • Track Tension: Tracks should be kept properly tensioned to avoid unnecessary wear and to ensure smooth movement. Over-tightened tracks can cause excessive wear on both the tracks and the undercarriage, while loose tracks can lead to track slippage and instability.
     
   • Rollers and Sprockets: Inspect the rollers and sprockets for signs of wear. Worn sprockets can lead to poor track performance, while damaged rollers can cause the tracks to wear unevenly. Grease the rollers and check for any dirt or debris that may hinder their movement.
     
   • Track Maintenance: Clean the tracks regularly to remove dirt, mud, and debris that could cause premature wear. In extreme conditions, such as working in harsh environments, it may be necessary to check the tracks more frequently.
     
4. Brake System Maintenance
   The braking system of the RK70M is essential for controlling the crane's movement and ensuring safety during operation. Regular brake inspections and maintenance help prevent accidents and extend the life of the brake components.
   • Brake Fluid Checks: Ensure that the brake fluid is at the proper level and free from contamination. If the fluid is low or dirty, it should be replaced immediately to maintain effective braking performance.
     
   • Brake Pad and Disc Inspections: Check the brake pads and discs for wear. Worn-out brake pads or discs should be replaced to maintain the crane's stopping power. Listening for unusual sounds, such as squealing or grinding, can also help identify brake problems early.
     
   • Hydraulic Brakes: Many Kobelco cranes, including the RK70M, use hydraulic brakes. Inspect the hydraulic lines for leaks and ensure that the system operates smoothly when the brakes are engaged.
     
5. Electrical System Maintenance
   The electrical system controls various functions of the crane, including lighting, control systems, and safety features. Regular inspections of the electrical components help identify potential issues before they lead to failures.
   • Battery Maintenance: Check the battery for corrosion around the terminals and ensure that it is holding a proper charge. Clean the terminals regularly and replace the battery if it shows signs of reduced performance.
     
   • Wiring and Connections: Inspect all wiring and electrical connections for signs of wear or damage. Damaged wires can cause shorts or malfunctions in the crane’s electrical systems. Ensure that connections are tight and secure to avoid electrical failure during operation.
     
   • Control System Checks: The crane’s control system should be tested regularly to ensure it is functioning correctly. If the control system is slow to respond or malfunctions, troubleshooting is needed to identify the source of the issue.
     

• Hydraulic Leaks: If you notice hydraulic fluid leaks, immediately check the hoses, seals, and fittings. Tighten or replace any damaged parts. Hydraulic leaks can cause a drop in pressure, leading to a loss of lifting power.
  
• Engine Overheating: If the engine temperature rises beyond the safe operating range, check the cooling system, including the coolant levels, radiator, and hoses. Clogged radiators or low coolant levels are common causes of overheating.
  
• Track Slippage: Track slippage can occur if the tracks are too loose. Tighten the track tension and inspect for any damage to the rollers or sprockets.
  
• Erratic Crane Movements: If the crane's movements are erratic or sluggish, check the hydraulic fluid levels and condition. Dirty fluid or low levels can lead to poor system performance.
  

Overview of the Case 650L Dozer
The Case 650L is a mid-size crawler dozer introduced by Case Construction Equipment, a division of CNH Industrial. Case has been producing earthmoving machinery since 1842, and the 650L represents a balance between compact maneuverability and sufficient pushing power for grading, backfilling, and light clearing. The 2016 model is powered by a Tier 4 Final diesel engine, electronically controlled for emissions compliance and fuel efficiency. With an operating weight around 18,000 lbs and a net horsepower of approximately 74 hp, the 650L is widely used in utility construction, land development, and municipal work.
Symptoms of the RPM Limitation
A common issue reported with the 650L is the engine failing to rev beyond 1300 RPM, even when the throttle is fully engaged. In such cases, the machine may still produce usable torque at low RPMs, and no warning lights or diagnostic codes appear on the dashboard. The air filter and fuel filters may be clean, and the machine may not exhibit smoke or misfiring—making the issue particularly frustrating to diagnose.
Initial Troubleshooting Steps
Operators typically begin by checking for common fuel delivery restrictions:

• Ensuring fuel shutoff valves are fully open
  
• Replacing both primary and secondary fuel filters
  
• Inspecting fuel lines for collapse or air leaks
  
• Removing the air filter to rule out intake blockage
  
• Running the machine with the fuel cap loosened to test for venting issues
  

• ECM (Engine Control Module): The onboard computer that manages engine performance, fuel delivery, and emissions.
  
• Decelerator Pedal: A foot pedal that temporarily reduces engine RPM, often used for fine grading or maneuvering.
  
• Throttle Position Sensor (TPS): A sensor that communicates pedal position to the ECM.
  

• Inspect the decelerator pedal for free movement and return spring tension
  
• Replace worn bushings or bearings in the pedal assembly
  
• Lubricate pivot points and check for corrosion or debris
  
• Calibrate the throttle position sensor if necessary using diagnostic software
  
• Periodically test pedal return during pre-operation checks
  

Choosing the right bucket size for an excavator is a critical decision that affects the efficiency, performance, and cost-effectiveness of a project. Excavators are versatile machines used in various industries, including construction, mining, landscaping, and demolition. The bucket, as the primary attachment, plays a significant role in determining how much material the machine can handle and how fast it can complete tasks such as digging, lifting, and grading.
This article explores the factors that influence bucket size selection, the impact of choosing the wrong size, and the guidelines for matching the bucket to specific tasks. Whether you're working on a large construction site or a small landscaping project, understanding the importance of bucket size is key to optimizing machine performance.
Understanding Bucket Size and Its Importance
The size of the bucket on an excavator directly impacts its capacity, reach, and digging efficiency. Bucket size is typically measured by its volume (cubic yards or cubic meters) and is generally chosen based on the material being handled, the machine’s size, and the specific job requirements.
An excavator bucket’s primary function is to scoop, transport, and dump material, such as dirt, gravel, rock, or debris. A bucket that is too small can result in frequent unloading and wasted time, while a bucket that is too large can lead to slower cycle times, increased fuel consumption, and potential stress on the machine.
Factors Influencing Bucket Size Selection

1. Excavator Size and Class
   The size of the excavator itself is one of the most important factors in determining the appropriate bucket size. Excavators come in different classes, from mini-excavators to large-scale machines used in mining or heavy construction. The bucket must be proportional to the excavator's size to ensure efficient operation and prevent undue strain on the machine.
   • Mini and Compact Excavators: Typically, mini-excavators have buckets with volumes ranging from 0.05 to 0.2 cubic yards. These smaller buckets are designed for tasks that require precision in tight spaces, such as landscaping or small construction projects.
     
   • Standard Excavators: Standard-sized excavators, which range from 10 to 40 tons, typically use buckets with volumes between 0.3 to 1.5 cubic yards. These are ideal for medium to large construction tasks, including digging trenches and loading material.
     
   • Large Excavators: Heavy-duty excavators, such as those used in mining, require buckets with volumes ranging from 2 to 10 cubic yards. These buckets are built to handle larger, more abrasive materials, such as rock or gravel, and are designed for efficiency in bulk excavation.
     
2. Material Type and Density
   The type of material being handled plays a significant role in bucket size selection. Denser materials, such as rock or compacted earth, will require a smaller bucket volume to maintain the excavator’s lifting capacity, while lighter materials, like loose soil or gravel, may allow for a larger bucket. Matching the bucket size to the material ensures that the excavator operates within its optimal performance range.
   • Soil and Dirt: Loose materials like soil, sand, and dirt can be handled with a larger bucket due to their lower density. These materials are less heavy, allowing for greater scoop capacity without overloading the machine.
     
   • Gravel and Rocks: Gravel, rocks, and other dense materials require a more compact bucket to ensure the machine can safely lift and transport the load without strain.
     
   • Heavy Materials (e.g., Concrete or Asphalt): For heavier, more compacted materials, such as concrete or asphalt, a smaller, stronger bucket with reinforced sides may be necessary to ensure efficient handling and prevent damage to the bucket or machine.
     
3. Worksite Conditions
   The type of worksite and the nature of the excavation project should also influence bucket size. Projects that involve precision digging, such as trenching for utilities or landscaping, may require a smaller, more specialized bucket. In contrast, bulk excavation tasks, like digging foundations or loading material into trucks, require larger buckets to improve efficiency.
   • Tight Spaces: For projects in tight spaces, a smaller bucket will allow for greater maneuverability, precision, and control.
     
   • Open Areas and Bulk Excavation: On large, open job sites where material needs to be moved quickly, a larger bucket will improve cycle times and productivity.
     
4. Cycle Time and Productivity
   Cycle time refers to the time it takes for an excavator to complete a full cycle, from digging a load to dumping it. Larger buckets tend to carry more material, which might reduce the number of cycles needed for a given task. However, if the bucket is too large for the excavator, it can reduce the speed of the cycle, increase fuel consumption, and lead to inefficient operation.
   Choosing the right bucket size can enhance productivity by ensuring that each cycle is optimized. The goal is to strike a balance between the capacity of the bucket and the machine’s ability to perform quickly and efficiently. Too large a bucket can slow down the cycle time due to the excavator struggling to lift the load, while too small a bucket will require more cycles to complete the same task.
   

1. Overloading the Excavator
   One of the most significant risks of choosing an oversized bucket is overloading the excavator. If the bucket is too large, it can lead to excessive stress on the engine, hydraulics, and undercarriage. This overloading can shorten the lifespan of the machine, increase maintenance costs, and lead to unexpected breakdowns. Furthermore, overloading the excavator can make the machine difficult to control, increasing the risk of accidents.
   
2. Reduced Efficiency
   A bucket that is too small can result in more frequent trips to unload material, reducing overall productivity. Operators may find themselves digging multiple times to fill a truck, which leads to wasted time and higher fuel consumption. While a smaller bucket might be necessary for certain tasks requiring precision, it’s essential to choose a size that can balance capacity with efficiency.
   
3. Increased Fuel Consumption
   Excavators are powered by diesel engines, and the size of the bucket can directly impact fuel consumption. A bucket that is too large can increase the load on the engine, causing it to burn more fuel per cycle. Similarly, a bucket that is too small will require additional cycles to move the same amount of material, leading to inefficiencies and higher fuel usage.
   

1. Evaluate the Project Requirements
   Consider the specifics of the project when selecting a bucket size. Bulk excavation projects, for example, may benefit from larger buckets, while projects that require more precision, such as trenching or grading, may need smaller, more specialized buckets.
   
2. Consult the Manufacturer's Guidelines
   The manufacturer’s recommendations are a helpful starting point for selecting a bucket. Excavator manufacturers provide guidelines on the appropriate bucket size for each machine model, taking into account the machine's lifting capacity and intended applications.
   
3. Consider the Operator’s Experience
   An experienced operator may be able to work with a slightly larger or smaller bucket, depending on the task at hand. However, for less experienced operators, it’s important to choose a bucket size that allows for better control and reduces the likelihood of overloading the machine.
   
4. Test Different Sizes
   If possible, testing different bucket sizes on the machine can provide valuable insights into how the excavator performs under different conditions. Operators should take note of the cycle times, fuel consumption, and overall ease of use with each bucket size to determine which is the most effective for the task.