Origins and Manufacturing Background
Thomas Equipment, based in New Brunswick, Canada, produced skid steer loaders mainly during the 1980s through early 2010s. Their machines were designed around simplicity and reliability, using common components such as Kubota diesel engines and Vickers hydraulic pumps. Production eventually ceased, with focus shifting toward compact walk‑behind units, but many units still operate today thomasloaders.com+3Heavy Equipment Forums+3SteelSoldiers+3.
General Reputation and Performance

• Reported as durable and basic, Thomas skid steers lack luxury but excel in functionality.
  
• Known for minimal electronics and simple mechanical layout, making them easy to repair.
  
• Operators in Manitoba and Maine frequently cited seeing these machines daily on jobsites, noting their long service life and robustness New Ag Talk+7skidsteerforum.com+7Heavy Equipment Forums+7.
  

• Hydrostatic transmission: Uses hydraulic fluid to connect engine power to drive wheels—offers smooth control and zero-radius turning.
  
• Kubota diesel engine: Compact, fuel-efficient, and easy to find parts for—trusted by many operators for reliability.
  
• ProTough series: Heavier-duty variants with reinforced frames and higher capacity components for professional use.
  
• Hydraulic motor/pump: Off-the-shelf parts that power drive and auxiliary systems; rebuildable and widely available.
  

• A machine with 5,000 hours still “ran like new” when regular maintenance was performed.
  
• Another user reported minimal breakdown over nine years in stone delivery and general contractor work.
  
• One veteran user insisted that routine upkeep and standard parts access made Thomas machines as dependable as Bobcats, if not more economical Facebook+12LawnSite+12Wikipedia+12Heavy Equipment Forums+3SteelSoldiers+3skidsteerforum.com+3Heavy Equipment Forums+1skidsteerforum.com+1.
  

• Thomas loaders are no longer manufactured, so OEM parts availability is limited. Many components must now be sourced via general suppliers or salvage parts.
  
• Some owners reported difficulty getting warranty support or technical assistance as the company evolved and ultimately exited skid steer production Heavy Equipment Forumsskidsteerforum.com.
  

Quote:“These machines are built tough... built to stand up to what is thrown in their way.” — operator of a T133 with high hours skidsteerforum.com+1skidsteerforum.com+1
“They were durable, simple, and most models came with Kubota engines.” — consistent positive review from upstate New York operator Haytalk+3Heavy Equipment Forums+3skidsteerforum.com+3

• A T133 in rural Maine was regularly used for construction and farming tasks—it served for nearly a decade with only minor repairs.
  
• Operators in Southern Canada used Thomas machines for landscape work, praising their stability, parts interchangeability, and ease of maintenance.
  
• Many replacement components like hoses, bearings, filters, and hydraulic parts remain available via third-party suppliers, thanks to the use of generic sub‑assemblies skidsteerforum.com.
  

• Confirm engine type, usually Kubota, and check parts support through engine suppliers.
  
• Investigate hydraulic component rebuild options, since pumps and motors use generic vendors.
  
• Prioritize machines with clear maintenance history—hours matter less if regular servicing was done.
  
• Have a shop equipped to repair older, less-standard skid steer designs—be prepared to DIY minor issues.
  

Leroi compressors are widely recognized for their reliability and durability in various industries, including construction, mining, and manufacturing. However, like all machinery, they are not immune to technical issues that can hinder performance. One of the common issues encountered by users is the identification and resolution of problems related to the engine driving the compressor.
In this article, we will explore the key steps involved in diagnosing engine problems in a Leroi compressor, the most frequent issues that may arise, and how to address them effectively.
The Role of the Engine in a Leroi Compressor
The engine in a Leroi compressor serves as the primary power source that drives the compressor's internal components. Whether the engine is diesel or gasoline-powered, its role is to generate the mechanical energy required to compress air, making it a crucial element in the overall performance of the system. A malfunctioning engine can lead to a lack of pressure, irregular compressor cycles, or complete failure to operate.
Common Engine Issues in Leroi Compressors
Several issues can arise with the engine in a Leroi compressor, which can affect both the engine's performance and the overall operation of the compressor. Below are some of the most commonly reported problems:

1. Engine Won’t Start
   • Description: One of the most frustrating issues is when the engine fails to start, preventing the compressor from operating.
     
   • Potential Causes:
     • Dead or weak battery.
       
     • Faulty starter motor or solenoid.
       
     • Clogged fuel filter or poor fuel quality.
       
     • Ignition system failure (worn spark plugs or coil issues).
       
   • Troubleshooting:
     • Check the battery charge and replace it if necessary.
       
     • Inspect the starter motor and solenoid for functionality.
       
     • Clean or replace the fuel filter and ensure the fuel is fresh and free from contaminants.
       
     • Inspect the ignition system components, including spark plugs, ignition coils, and wires.
       
2. Engine Stalling or Losing Power
   • Description: If the engine stalls during operation or struggles to maintain power, it can cause intermittent compressor performance or failure to compress air effectively.
     
   • Potential Causes:
     • Insufficient fuel supply or fuel line blockage.
       
     • Air filter clogged with dirt or debris.
       
     • Malfunctioning fuel injector or carburetor.
       
     • Problems with the engine’s governor or speed control system.
       
   • Troubleshooting:
     • Ensure that the fuel tank is full and that the fuel lines are clear and free of obstructions.
       
     • Replace or clean the air filter.
       
     • Inspect the fuel injectors or carburetor for clogs or wear, and clean or replace as necessary.
       
     • Test the governor and speed control system for proper operation.
       
3. Engine Overheating
   • Description: Overheating is another common issue, especially during extended periods of operation, and can lead to severe engine damage if not addressed promptly.
     
   • Potential Causes:
     • Low coolant levels or coolant leaks.
       
     • Blocked radiator or cooling fins.
       
     • Worn or malfunctioning water pump.
       
     • Clogged or dirty oil cooler.
       
   • Troubleshooting:
     • Check the coolant level and top it up if necessary. Look for any signs of leaks around the cooling system.
       
     • Inspect the radiator for debris or blockage, and clean it thoroughly.
       
     • Test the water pump for proper operation and replace if needed.
       
     • Clean the oil cooler and ensure that it is functioning as intended.
       
4. Excessive Engine Noise or Vibration
   • Description: Unusual engine noise or excessive vibration can be a sign of underlying issues that require immediate attention.
     
   • Potential Causes:
     • Loose engine components, such as bolts or belts.
       
     • Worn or damaged bearings in the engine or compressor unit.
       
     • Engine misfire or fuel system issues.
       
   • Troubleshooting:
     • Tighten any loose bolts or fasteners on the engine and compressor unit.
       
     • Inspect the belts for wear and ensure proper tension.
       
     • Test the engine for misfire issues, and replace the faulty components such as spark plugs or fuel injectors.
       
5. Excessive Exhaust Smoke
   • Description: If the engine is producing more exhaust smoke than normal, it could indicate internal engine problems or a failure in the fuel system.
     
   • Potential Causes:
     • Worn engine rings or cylinders.
       
     • Fuel injector problems causing an overly rich fuel mixture.
       
     • Leaking exhaust valves or seals.
       
   • Troubleshooting:
     • Perform a compression test to check for worn engine rings or damaged cylinders.
       
     • Inspect the fuel injectors and replace any faulty components.
       
     • Check the exhaust system for leaks and replace any worn seals or valves.
       

1. Regularly Change the Engine Oil: Changing the engine oil at regular intervals helps prevent buildup of contaminants and ensures proper lubrication, reducing wear and tear on engine components.
   
2. Clean or Replace the Air Filter: The air filter is essential for keeping dirt and debris out of the engine. A clean air filter ensures the engine runs efficiently and reduces the risk of overheating.
   
3. Inspect the Fuel System: Regularly check the fuel lines, fuel filter, and fuel tank for any signs of contamination or leaks. Contaminated fuel can lead to clogged injectors and engine stalling.
   
4. Monitor Coolant Levels: Keep an eye on the coolant levels and inspect the cooling system for any leaks or obstructions. Overheating is a common cause of engine failure.
   
5. Check Belts and Hoses: Regularly inspect belts and hoses for wear, cracks, or damage. Faulty belts or hoses can lead to engine overheating or loss of power.
   

Introduction to Aitik
Located just south of Gällivare near the Arctic Circle, the Aitik copper mine is one of Europe’s largest open-pit operations. Owned by Boliden AB, it began production in 1968 and has since evolved into a high-efficiency mining complex extracting copper, gold, and silver. Despite its remote location and harsh climate, Aitik has become a symbol of technological advancement and sustainable mining.
Terminology Notes

• Open-Pit Mining: A surface mining technique where minerals are extracted from a large excavation.
  
• Ore Grade: The concentration of valuable minerals within the ore.
  
• Autogenous Grinding (AG): A process where ore grinds itself without additional steel balls.
  
• Flotation: A method of separating minerals using differences in their hydrophobic properties.
  
• Pushback: A mining strategy involving sequential excavation to expand the pit.
  

• Host Rock: Precambrian volcanic and granitic formations
  
• Orebody: Disseminated chalcopyrite with traces of gold, silver, and molybdenum
  
• Average Copper Grade: ~0.25–0.4%
  
• Gold Content: ~0.14 g/ton
  
• Silver Content: ~1.7 g/ton
  

• Mining Method: Drill-blast-shovel with truck haulage
  
• Depth: Up to 450 meters
  
• Equipment Used:
  

• Bucyrus and P&H electric shovels
  
• Komatsu H485 hydraulic excavators
  
• Caterpillar 789, 793, and 797 haul trucks
  
• In-pit crushers and 7 km conveyor systems
  

• Crushing: In-pit and semi-mobile crushers
  
• Grinding: AG mills with 2,200 tons/hour capacity
  
• Flotation: Microcel columns for copper, gold, and silver recovery
  
• Control System: ABB’s 800xA automation platform
  
• Output: Pressure-filtered concentrate shipped to Rönnskär smelter
  

• Initial Capacity (1968): 2 million tons/year
  
• Post-Expansion (2010): 36 million tons/year
  
• Current Throughput: Over 40 million tons/year
  
• Productivity: ~55 tons of ore per man-hour
  
• Life Expectancy: Extended to at least 2029
  

• Reclamation Planning: Integrated from the mine’s inception
  
• Electrification Project:
  • CAT 795 trucks retrofitted with pantograph-style current collectors
    
  • 3 km of electric lanes installed
    
  • Reduced diesel consumption and emissions
    
• Gender Equality: Nearly equal representation of male and female operators
  
• Employment: Largest private employer in Gällivare with ~900 staff
  

• Aitik: Largest by volume, highly automated, low-grade ore
  
• Kiruna (Sweden): Underground iron ore mine, deeper but less automated
  
• Neves-Corvo (Portugal): Polymetallic underground mine, higher ore grades
  
• Røros (Norway): Historic copper mine, now closed
  

• Regular grading of haul roads to prevent tire damage
  
• Scheduled inspections of crushers and conveyors
  
• Use of dielectric grease on electrical connectors
  
• Real-time monitoring of equipment via centralized control
  
• Safety drills and automated shutdown protocols
  

Automation, Electrification & AI Transforming the Jobsite
Across global projects—from autonomous hauling trucks operating in Western Australia to electric excavators in Sweden—construction equipment is evolving rapidly. AI-guided machines, remote-controlled loaders, and energy-efficient electric counterparts are moving from pilot tests to real-world use. Major manufacturers like Caterpillar, Komatsu, Volvo, and Liebherr are investing heavily in these domains. Readiness for safer, cleaner, and more efficient workflows marks a new era in heavy machinery Highways Today.
Why Hi‑Tech Matters in Machinery

• Increased Productivity: Autonomous machines perform repetitive tasks non-stop, enabling crews to focus on more complex jobs.
  
• Enhanced Safety: Remote operation reduces worker exposure to high-risk areas.
  
• Data-Driven Decision-Making: Sensors and telematics allow sites to monitor machine health, productivity, and fuel usage in real time.
  
• Environmental Benefits: Electric excavators and autonomous systems reduce emissions and energy use.
  

• Autonomous systems: Machines operating without a human driver, often guided by GPS, AI, and geo-fences.
  
• Electrification: Transitioning from diesel to battery or hybrid powertrains to reduce emissions and noise.
  
• Machine learning & AI: Used to predict maintenance needs, optimize digging patterns, and manage operations.
  
• Fleet telematics: Sensors and communications systems tracking machine usage, location, and health.
  
• Remote operation: Operators use control stations or VR/AR to drive machinery from a distance.
  

• Geo-fence: A virtual boundary that restricts where machinery can operate, often embedded in autonomous setups.
  
• After‑cooling: A system used to cool air entering the engine, improving combustion efficiency—critical in turbocharged systems.
  
• Built Robotics ExoSystem: An aftermarket kit enabling autonomy on existing excavators via cameras, GPS, sensors, and software Boom & Bucket.
  
• Fleet management: Coordinating multiple machines remotely to maximize uptime, handle maintenance, and improve logistics.
  

• A major solar project in Texas saw autonomous trenching implemented by retrofit systems, showcasing how autonomy improves precision and safety. Equipment managers monitored performance via centralized dashboards to validate productivity and ROI Boom & Bucket.
  
• On another jobsite, haul trucks operated driverlessly on looped paths, demonstrating long-duration machine autonomy in a real environment facebook.com+7Highways Today+7arxiv.org+7.
  
• Sensors and AI-enabled cranes began self-reporting maintenance needs before breakdowns occurred, leading to fewer unscheduled shutdowns on high-profile infrastructure builds Highways Today+1Boom & Bucket+1.
  

• Assess compatibility: Determine whether autonomy or electrification suits your existing fleet. Retrofit kits may work, but newer electric models offer long-term efficiency.
  
• Start with pilot projects: Test new technologies on limited sites to measure performance before scaling up.
  
• Train crews and managers: Success requires adoption from both field operators and equipment leaders. Education is key.
  
• Align incentives: Ensure that efficiency gains benefit both bottom-line costs and workforce performance metrics.
  
• Collaborate with providers: Work with tech vendors who offer integration, training, and technical support for new systems.
  

Volvo EC55 is a highly reliable and versatile mini-excavator that is widely used in construction, landscaping, and urban development. However, like any heavy equipment, it can encounter issues that affect its performance. One such issue is the overheating of the control valve block and problems related to oil flow, which can lead to inefficiency, damage, or even failure if not addressed properly.
In this article, we’ll break down the potential causes behind these issues, how to troubleshoot them, and what steps can be taken to prevent these problems in the future.
Understanding the Control Valve Block and Its Role
The control valve block is a critical component in hydraulic systems, directing hydraulic fluid to various parts of the machine for operation. It controls the flow of hydraulic oil to the machine's attachments and main components, allowing the operator to perform tasks such as digging, lifting, and rotating.
Overheating of the control valve block can lead to a variety of problems, such as erratic performance, slow response times, or even complete failure of certain hydraulic functions. In the case of the Volvo EC55, overheating could also be related to oil problems, including poor circulation, contamination, or insufficient cooling.
Common Causes of Control Valve Block Overheating and Oil Issues
Several factors could contribute to overheating in the control valve block and oil-related problems in the Volvo EC55. Below are some of the common causes:

1. Low Hydraulic Oil Levels
   • Description: Low oil levels can cause poor circulation and increased friction within the system, leading to overheating.
     
   • Symptoms: Erratic hydraulic movements, slower machine responses, and excessive noise from the pump.
     
2. Contaminated Hydraulic Oil
   • Description: Contaminants such as dirt, debris, or water in the hydraulic fluid can obstruct the oil flow and cause the system to overheat.
     
   • Symptoms: Decreased performance, increased pressure on the pump, and discolored or dirty hydraulic oil.
     
3. Clogged or Dirty Oil Filters
   • Description: A clogged filter can restrict oil flow, increasing the load on the hydraulic system and causing overheating.
     
   • Symptoms: Reduced hydraulic power, slow response time, and overheating of the control valve block.
     
4. Faulty Hydraulic Pump
   • Description: A malfunctioning pump may fail to deliver adequate oil pressure, leading to overheating as the system works harder to compensate.
     
   • Symptoms: Irregular or weak hydraulic movement, overheating, and unusual noises from the pump.
     
5. Blocked Oil Coolers
   • Description: The oil cooler is responsible for regulating the temperature of the hydraulic oil. If it becomes blocked, it can cause the oil to overheat.
     
   • Symptoms: The control valve block may become excessively hot, and the hydraulic oil temperature may rise beyond safe limits.
     
6. Improper Oil Viscosity
   • Description: Using the wrong type of hydraulic oil (incorrect viscosity) can cause oil to flow poorly, leading to increased friction and heat generation in the system.
     
   • Symptoms: Overheating of the hydraulic system and irregular machine movement.
     
7. Worn or Damaged Control Valve
   • Description: If the control valve itself becomes worn or damaged, it can cause improper oil flow, leading to overheating and inefficient operation.
     
   • Symptoms: Slow or jerky movements of the attachments, erratic control of functions, and the valve block heating up quickly.
     

1. Check Hydraulic Oil Levels
   • Ensure that the hydraulic oil is at the recommended level. Low oil levels can directly affect the oil circulation and result in overheating.
     
   • Top up the oil if necessary, using the type and grade recommended by Volvo.
     
2. Inspect for Contaminated Oil
   • Check the color and condition of the hydraulic oil. If the oil appears murky, discolored, or has a burnt smell, it may be contaminated.
     
   • Drain the contaminated oil and replace it with clean, fresh hydraulic oil. Be sure to change the oil filter at the same time.
     
3. Clean or Replace Oil Filters
   • Inspect the hydraulic oil filters for clogs or blockages. If the filters are clogged, they will restrict oil flow and cause increased pressure within the system, leading to overheating.
     
   • Clean the filters if they are reusable, or replace them with new ones if necessary.
     
4. Examine the Hydraulic Pump
   • Check for signs of wear or malfunction in the hydraulic pump. Ensure it is delivering adequate oil pressure. Low pressure or inconsistent operation can indicate a faulty pump.
     
   • If the pump is damaged, it may need to be repaired or replaced to restore proper oil flow and prevent overheating.
     
5. Inspect the Oil Cooler
   • Make sure that the oil cooler is not blocked or clogged with debris. A blocked cooler will prevent the hydraulic oil from being properly cooled, causing it to overheat.
     
   • Clean the cooler and remove any debris to allow for proper heat dissipation.
     
6. Verify Oil Viscosity
   • Ensure that you are using the correct viscosity of hydraulic oil. If the oil is too thick or too thin, it can lead to poor oil flow and overheating.
     
   • Refer to the Volvo EC55’s operator’s manual to check the recommended oil viscosity for the specific operating conditions.
     
7. Examine the Control Valve
   • If the control valve is overheating or showing signs of damage, it may need to be replaced. Look for leaks, cracks, or excessive wear on the valve itself.
     
   • If the valve is worn, it may no longer function properly, causing oil flow problems and overheating.
     

1. Regularly check and top off hydraulic oil to ensure optimal fluid levels.
   
2. Change hydraulic oil and filters periodically to prevent contamination.
   
3. Clean the oil cooler regularly to ensure efficient heat dissipation.
   
4. Inspect hydraulic system components such as the pump and control valve for wear and tear.
   
5. Ensure proper oil viscosity based on the machine's operating conditions.
   
6. Keep the machine clean, especially around hydraulic components, to avoid debris buildup.
   

Understanding the Genie Z-45/25J
The Genie Z-45/25J is a popular articulating boom lift used in construction, maintenance, and industrial applications. With a working height of 51 feet and a horizontal outreach of 25 feet, it offers flexibility and reach in tight spaces. The “J” in the model name refers to the jib boom, which adds articulation for precise positioning.
Terminology Notes

• Articulating Boom Lift: A type of aerial platform with multiple pivot points for maneuvering around obstacles.
  
• Bi-Energy System: Allows operation via diesel engine or electric motor, enhancing versatility.
  
• ALC-500 Circuit Board: The onboard controller managing lift functions and diagnostics.
  
• Platform Control Pedal: A foot-activated switch that enables movement when depressed.
  
• Yellow Fuse: A 20A or 25A fuse often linked to control circuits or safety interlocks.
  

• Thermal overload or heat-related failure in a control circuit
  
• Voltage drop or parasitic drain affecting the control board
  
• Faulty relay or intermittent ground causing system resets
  

• Battery voltage instability: Low voltage can trigger safety shutdowns
  
• Loose ground connections: Especially near the control box or fuse panel
  
• Corroded fuse terminals: Can cause intermittent contact and overheating
  
• Faulty joystick or pedal switches: May send erratic signals to the controller
  

• Inspect the yellow fuse socket for heat damage or corrosion
  
• Check battery voltage under load; replace if below 12.4V
  
• Test pedal switch continuity with a multimeter
  
• Examine the ALC-500 board for cracked solder joints or swollen capacitors
  
• Verify ground connections at the chassis and control box
  

• Clean fuse terminals with contact cleaner every 6 months
  
• Replace fuses with OEM-rated components only
  
• Keep the control box sealed and dry to prevent condensation
  
• Use dielectric grease on connectors to prevent corrosion
  
• Log shutdown events to identify patterns in timing or temperature
  

Engine and Application Background
The Detroit Diesel Series 92 engine, introduced in 1974, became a workhorse across North America—powering buses, motorhomes, fire trucks, construction equipment, and heavy-duty grain haulers. The 6V‑92 was the six-cylinder V-block variant, displacing 9.0 liters and producing around 270 hp (up to 335 hp in turbocharged versions), with torque commonly exceeding 1,300 lb-ft.
The engine’s two-stroke design meant it fired every revolution, delivering more immediate power compared to four-stroke engines. It used replaceable iron liners, delivered high torque at low rpm, and was available with options like turbocharging and aftercooling. While it eventually fell out of favor due to emissions and noise regulations, its robustness secured its place in heavy industry for decades.
Grain Truck Story and Restoration Effort
In one remarkable restoration project, a grain hauler powered by a Detroit Diesel 6V‑92 was brought back to life after more than twenty years of inactivity. The engine had long been silent due to neglect, heat damage, and age-related issues. The revival involved flushing old fluids, replacing filters, inspecting the blower system, and performing oil analysis.
Despite initial concerns, the engine restarted with strong, steady combustion—a testament to the resilience of the Series 92 line. Upgrades included switching to modern low-ash diesel lubricants and improving the truck's cooling system, ensuring it could meet modern standards of reliability and safety.
Technical Terms Glossary

• Series 92 engine: A family of V-type, two-stroke diesel engines built by Detroit Diesel, used widely in commercial and industrial vehicles.
  
• 6V‑92: A 6-cylinder, V-block engine displacing 92 cubic inches per cylinder (total of 552 in³ or 9.0 L), with horsepower ranging from 270 to 335 depending on configuration.
  
• Two-stroke diesel: An engine cycle where every crankshaft revolution produces power, offering more immediate torque but requiring forced induction.
  
• Blower (supercharger): An integral part of two-stroke diesel operation, injecting air into the combustion chamber. Its failure is often catastrophic.
  
• DDEC (Detroit Diesel Electronic Controls): A control module used in later versions of the engine to manage fuel delivery, timing, and diagnostics.
  
• Oil analysis: A maintenance tool that evaluates wear metals and contaminants in engine oil, revealing the condition of internal components.
  
• Low-ash oil: Specialized oil with reduced ash content to prevent buildup on cylinder walls and reduce emissions, crucial for two-stroke diesels.
  

• Perform early oil analysis to detect metal wear and contamination.
  
• Flush and clean fuel and cooling systems before attempting startup.
  
• Replace the blower or inspect for wear—it is a common failure point.
  
• Use proper low-ash oil formulated for two-stroke diesel engines.
  
• Avoid untrained service techs—two-stroke Detroits require experienced hands.
  
• Break in revived engines slowly—gradual return to full loads reduces the chance of failure.
  

The Big Purchase
A landfill operator in rural Mississippi had been renting excavators for thousands annually. Determined to reduce costs, he dedicated himself to finding the right machine and finally bought a Komatsu PC50UU excavator in solid condition, with no leaks after twelve hours of use, tracks and undercarriage still tight, and oil samples clean.
Paying $8,500, this investment replaced more than $10,000/year in rental costs. He planned upgrades like painting the body in newer Komatsu yellows and blacks and adding a two-way remote hydraulic circuit to power an auger.
Improvements and Fabrication Plans
He already owns a burner table and has built front-end thumbs for gear in the past. He intends to build two types of thumbs: one that pins on under the bucket and another under the boom. The latter offers better reach, while the former is easier to remove—saving on fuel when loading trucks. The thumb will share the same pin as the bucket and use a rabbit valve to control its hydraulic function.
Technical Terms Glossary

• Grey-market machine: Imported outside official dealer networks—often reliable but lacking factory warranty or support.
  
• Oil analysis: A lab test to assess engine fluid condition; absence of metal debris or sludge suggests low wear.
  
• Final drive: The gearing in the undercarriage that powers the tracks; intact blades and no play usually indicate healthy travel motors.
  
• Two-way remote hydraulic circuit: An auxiliary hydraulic line that allows bi-directional fluid flow—used for tools like remote-operated augers or thumbs.
  
• Burner table: A fabrication platform used to cut metal shapes for custom attachments like thumbs and rakes.
  

• Perform oil analysis before purchase to assess internal wear
  
• Inspect undercarriage and final drives for tightness and absence of leaks
  
• Use fabrication tools like a burner table to build job-specific attachments
  
• Plan hydraulic circuits for future accessories like augers or thumbs
  
• Pin-on thumbs vs boom-mounted thumbs: select based on ease of removal vs operational flexibility
  

John Deere's 672CH motor grader is widely used in construction, road maintenance, and other heavy-duty applications due to its reliability and power. However, like any piece of sophisticated machinery, it can occasionally present error codes that may affect its performance. These error codes are designed to alert the operator to potential issues within the grader’s systems. Understanding and resolving these codes is essential for maintaining the equipment's efficiency and avoiding costly downtime.
In this article, we will discuss common error codes for the John Deere 672CH motor grader, potential causes for these errors, and the steps you can take to troubleshoot and resolve the issues.
What Are Error Codes on John Deere 672CH Motor Graders?
Error codes on a motor grader are part of the machine’s diagnostic system. These codes are generated when the machine’s sensors detect abnormalities or faults in the operation of various components such as the engine, transmission, hydraulics, or electrical systems. The codes are typically displayed on the machine’s monitor or diagnostic screen, alerting the operator to the specific issue.
The John Deere 672CH motor grader is equipped with an advanced diagnostic system that monitors multiple parameters to ensure optimal performance. When an issue arises, the system provides a corresponding error code that helps technicians or operators pinpoint the problem.
Common Error Codes and Their Causes
There are several common error codes that operators may encounter while using the John Deere 672CH motor grader. Below are some examples of these codes and their potential causes:

1. Error Code 611 (Engine Overheat)
   • Description: This error code indicates that the engine temperature is higher than normal, which can lead to engine damage if left unaddressed.
     
   • Possible Causes:
     • Low coolant levels or a coolant leak.
       
     • Clogged or malfunctioning radiator.
       
     • Faulty thermostat or water pump.
       
     • Blocked airflow through the radiator.
       
   • Troubleshooting:
     • Check the coolant levels and top them up if necessary.
       
     • Inspect the radiator for any debris or blockages that may prevent proper airflow.
       
     • Test the thermostat and water pump to ensure they are working correctly.
       
2. Error Code 526 (Hydraulic Pressure Low)
   • Description: This code indicates that the hydraulic pressure is lower than the system's required levels.
     
   • Possible Causes:
     • Low hydraulic fluid levels.
       
     • Worn or damaged hydraulic pump.
       
     • Leaking hydraulic lines or fittings.
       
   • Troubleshooting:
     • Check the hydraulic fluid levels and ensure they are within the recommended range.
       
     • Inspect the hydraulic system for any visible leaks.
       
     • Test the hydraulic pump to ensure it is providing adequate pressure.
       
3. Error Code 543 (Transmission Fault)
   • Description: A transmission fault code indicates a problem with the machine’s transmission system.
     
   • Possible Causes:
     • Low transmission fluid.
       
     • Faulty transmission sensors.
       
     • Worn transmission components.
       
   • Troubleshooting:
     • Check and top off the transmission fluid if necessary.
       
     • Inspect the transmission sensors and wiring for any faults.
       
     • If the problem persists, consider having the transmission components inspected by a professional.
       
4. Error Code 911 (Electrical System Issue)
   • Description: This code typically points to an issue with the machine’s electrical system, including battery or charging system problems.
     
   • Possible Causes:
     • Faulty alternator.
       
     • Weak or dead battery.
       
     • Loose or corroded electrical connections.
       
   • Troubleshooting:
     • Check the battery charge and replace it if necessary.
       
     • Inspect the alternator and charging system to ensure they are functioning correctly.
       
     • Clean and tighten any loose or corroded electrical connections.
       
5. Error Code 729 (Braking System Malfunction)
   • Description: A braking system malfunction can be critical, as it affects the ability to stop the grader effectively.
     
   • Possible Causes:
     • Low brake fluid levels.
       
     • Worn brake pads or damaged components.
       
     • Issues with the braking system’s hydraulic pressure.
       
   • Troubleshooting:
     • Check the brake fluid levels and top them up if needed.
       
     • Inspect the brake pads for wear and replace them if necessary.
       
     • Test the hydraulic pressure in the braking system and repair any leaks or faults.
       

1. Consult the Operator’s Manual
   • The first step when encountering an error code is to consult the operator’s manual. The manual will provide a list of error codes, their descriptions, and possible causes. This information is invaluable in narrowing down the potential problem.
     
2. Perform Basic Visual Inspections
   • Check for obvious issues such as low fluid levels, leaks, or damaged parts. These are often the cause of error codes and can be easily fixed by topping up fluids or replacing damaged components.
     
3. Use the Diagnostic System
   • The John Deere 672CH is equipped with a diagnostic system that can provide more detailed information about the error codes. This system may offer specific data that can help you pinpoint the exact issue, such as hydraulic pressure readings or sensor data.
     
4. Clear the Error Code
   • After addressing the issue, you can clear the error code from the system. This is typically done through the machine’s diagnostic interface. Clearing the code will reset the system, and you can monitor if the issue persists.
     
5. Contact a Professional Technician
   • If you are unable to resolve the issue yourself, it’s best to contact a professional technician. John Deere service technicians have specialized knowledge and tools to diagnose and repair more complex issues that may not be easily fixed on-site.
     

1. Check Fluid Levels Regularly: Ensure that coolant, hydraulic fluid, and transmission fluid are at the recommended levels.
   
2. Inspect the Cooling System: Clean the radiator and check for leaks to prevent overheating.
   
3. Test the Electrical System: Regularly check the battery, alternator, and wiring for any issues.
   
4. Maintain the Brakes and Hydraulic System: Regularly inspect and maintain the braking and hydraulic systems to avoid malfunctions.
   
5. Follow a Scheduled Maintenance Plan: Adhere to the manufacturer’s recommended maintenance schedule to keep the machine in peak condition.
   

Origins of the Hy-Hoe
The Hy-Hoe excavator was a product of the Hydraulic Machinery Company, Inc., based in Milwaukee, Wisconsin. Emerging in the late 1950s, it was among the earliest fully hydraulic excavators in the United States. Its name—“Hy-Hoe”—was a clever nod to its hydraulic nature and its function as a digging machine, or “hoe.”
Terminology Notes

• Hydraulic Excavator: A machine that uses hydraulic fluid and cylinders to power its digging arm and other components.
  
• Slew: The rotational movement of the upper structure of an excavator. Early Hy-Hoes had a limited 270° slew.
  
• Track Hoe: A colloquial term for a tracked hydraulic excavator.
  
• Detroit Diesel: A popular engine brand used in many heavy machines, known for its durability and distinctive sound.
  

• Engine: 3-cylinder Detroit Diesel
  
• Slew Range: 270° (not full 360°)
  
• Mounting: Some models were truck-mounted for mobility
  
• Hydraulic System: Early open-center design with basic controls
  
• Cab: Minimalistic, often lacking modern comforts or safety features
  

• Yumbo: A French hydraulic excavator brand that pioneered 360° rotation by 1954.
  
• Gradall: An American brand from Ohio, known for its telescoping boom and truck-mounted designs.
  
• Hy-Hoe: Focused on rugged simplicity, with limited slew and basic hydraulics, but influential in design.