The L785 and Its Mechanical Simplicity
The New Holland L785 skid steer loader was introduced in the 1980s as part of New Holland’s push into compact construction equipment. With a rated operating capacity of around 1,850 pounds and a robust mechanical drive system, the L785 became a popular choice for contractors, farmers, and municipalities. It featured a chain-driven transmission, mechanical hand controls, and a straightforward hydraulic system that made it easy to service and durable in harsh conditions.
New Holland, founded in Pennsylvania in 1895, had by then become a global brand under the Fiat Group umbrella. The L785 was one of its most successful early skid steer models, with thousands sold across North America and Europe. Its mechanical steering system—based on dual lever control of hydrostatic pumps—offered precise maneuverability but required periodic adjustment to maintain balance and responsiveness.
Steering System Layout and Terminology
The L785 uses a dual-lever steering system connected to two hydrostatic pumps. Each lever controls the flow and direction of hydraulic fluid to one side of the drive motors. When both levers are pushed forward evenly, the machine moves straight ahead. Uneven lever response or drift indicates a need for adjustment.
Terminology annotation:
- Hydrostatic pump: A variable displacement pump that controls fluid flow to drive motors, allowing infinite speed variation and direction control.
- Steering linkage: Mechanical rods and joints connecting the control levers to the pump swash plates.
- Neutral position: The lever setting where no fluid is directed to the drive motors, keeping the machine stationary.
- Drift: Unintended movement to one side when levers are centered, often caused by misalignment or wear.
Symptoms of Misalignment and Steering Imbalance
Common signs that the steering system needs adjustment include:

• Machine veers left or right when both levers are centered
  
• One lever feels stiffer or looser than the other
  
• Uneven response when reversing or turning
  
• Difficulty maintaining a straight line during travel
  

• Park the machine on level ground and block the wheels
  
• Remove the seat and access panel to expose the pump control arms
  
• Locate the adjustment bolts or linkage rods connected to each pump
  
• Move the levers to neutral and observe the pump arms—they should be centered and not actuating flow
  
• Adjust the linkage rods or bolts incrementally to center the pump arms
  
• Test the machine by driving forward and backward, noting any drift
  
• Repeat adjustments until both levers produce equal response and the machine tracks straight
  

• Use thread-locking compound on adjustment bolts to prevent loosening
  
• Replace worn bushings or pivot pins during adjustment to eliminate play
  
• Lubricate all linkage points with high-quality grease
  
• Check hydraulic fluid level and condition before testing
  

• Inspect linkage and pump arms every 250 hours
  
• Replace worn bushings and bolts annually
  
• Keep hydraulic fluid clean and topped off
  
• Avoid aggressive lever movements that stress the linkage
  
• Store the machine indoors to prevent corrosion on control components
  

Definition and Role of Ten Ton Trailers
A “ten ton trailer” generally refers to trailers designed for a payload capacity of around 20,000 pounds (≈ 10 short tons), excluding the trailer’s own weight. These are heavy-duty haulage trailers used for transporting large equipment, construction machinery, vehicles, or other bulky loads. Key terms to know:

• GVWR (Gross Vehicle Weight Rating): The total allowable weight of trailer plus load.
  
• Payload: How much actual cargo the trailer can carry (GVWR minus trailer’s empty weight).
  
• Deck or Deck Length: The flat surface where cargo is placed; some trailers have beavertails or ramps for easier loading.
  
• Axles: Number and rating affect how weight is distributed; tandem (two) or more axles are common.
  
• Suspension: Leaf springs, slipper springs, or more advanced setups to handle load, shock, and durability.
  

• Payload: ~20,000 lbs (≈ 9,070 kg) when using proper hitch and weight distribution.
  
• Empty (dry) weight: often ~5,500-6,000 lbs (≈ 2,500-2,800 kg) for tag or deckover style trailers of similar capacity.
  
• Deck length: Typically about 25 ft deck (20 ft flat + 5 ft beavertail or ramp). Some models offer longer decks or flat combinations.
  
• Deck width: Usually in range 8′ to ~8.5′ (96″-102″) depending on trailer class.
  
• Deck height: Around 34″ (≈ 86-90 cm) measured from ground when loaded.
  
• Axles: Two axles, each rated ~10,000 lb, often with oil bath hubs for durability.
  
• Brakes: Electric self-adjusting, sometimes 12-1/4″ × 3-3/8″ or similar.
  
• Frame: Usually heavy channel or I-beam steel, high tensile where possible. Crossmembers every ~16-24″ on center.
  

• Load King is a long-established trailer manufacturer (since 1956) known for custom designs and standard models for heavy hauling. They produce tag-along trailers, deckovers, beavertails, etc.
  
• Hudson Equipment Trailers likewise makes Pro-Series GT models with deckovers and heavy duty tag trailers.
  
• There's also a trend of tri-axle trailers for slightly higher capacity or increased stability, e.g. “9- and 10 ton custom deckover tri-axle” models.
  

• Deckover / Deck-over: Flat deck that sits above wheels; often with a beavertail/ramp for loading.
  
• Tag-along: A trailer that attaches behind a tow vehicle, sometimes with ramps or beavertails.
  
• Gooseneck: Hitch that connects in the bed of a truck, allowing better weight distribution; sometimes options for removable or adjustable gooseneck designs.
  
• Dovetail: The back of the trailer slopes downward (beavertail style) to reduce incline when loading; some ramps are removable or spring-assisted.
  

• High payload capacity with dual or tandem 10,000 lb axles.
  
• Good strength in frame and steel materials when built with high: channel steel, I-beams, high tensile steel.
  
• Versatility: with ramps/beavertails and tie-downs, they can haul equipment, vehicles, bulk materials.
  
• With LED lights, sealed wiring, better brake setups, durability improves.
  

• Empty weight is heavy, reducing the net payload if towing vehicle isn’t up to spec.
  
• Beavertail/ramp mechanisms can wear, especially springs or hinges.
  
• Brake maintenance is critical, especially electric brakes, wiring, and hub bearings.
  
• Road legal constraints vary: axle load limits, bridge weight limits, width restrictions.
  

• Use good hitch (proper capacity, correct height) and ensure weight distribution over the axles to avoid overloading a single axle.
  
• Regular maintenance schedule: check tires, tires pressure; inspect frame welds; grease suspension parts; check electrical wiring and lights.
  
• For ramps/beavertails: weekly or before heavy usage, lubricate hinges, check spring tension, ensure locking mechanisms are safe.
  
• If hauling frequently, consider going to tri-axle or higher decking width for stability.
  
• Be aware of road regulations in your area: maximum GVWR, width, brakes required.
  

• Lighter but stronger steel (higher tensile strength) to reduce trailer empty weight.
  
• Improved brake systems (electric self-adjusting, better drum or disc options).
  
• Better lighting (LED), sealed harnesses to prevent corrosion.
  
• Accessory options (tool trays, toolbox lids, adjustable ramps).
  

• In many U.S. counties and agricultural areas, there has been pushback or negotiation over “10-ton roads” or bridges: roads built for vehicles/trailers up to 10 ton per axle or per certain load class. Farmers and equipment haulers often lobby to maintain or upgrade roads to support heavier loads. In one case, Minnesota farmers pressed for roads that can handle 10-ton loads so they can transport harvests more efficiently.
  
• A manufacturer recently unveiled a 10-ton gooseneck trailer with nearly 20,000 lb payload, over 38′ overall length, showing demand for longer, more capable units in sectors like oilfield, logging, and large equipment moving.
  

Overview of the MF135 Tractor
The Massey Ferguson 135 (MF135) is a classic utility tractor first introduced in the mid-1960s and produced until the mid-1970s. It belongs to the MF100 series, made in Coventry, England. Its appeal comes from simple and rugged mechanics, making it popular still in many regions — both for small farms and contract maintenance work.
Key specs to know:

• Engine: ~45-47 hp (≈35-35 kW), commonly the Perkins AD3.152 three-cylinder diesel.
  
• PTO (rear) Type: 540 RPM.
  
• 3-point hitch: Category I / Category II depending on version, rear lift capacity around 2,800-3,150 lbs (~1,270-1,430 kg) in many models.
  
• Hydraulics: Enough to lift implements via the 3-point, though not very high flow compared to modern large tractors.
  

• Flail rotor with flail blades or hammer blades that rotate via PTO.
  
• A gearbox, rotor shaft, guards, side skids or roller, and possibly hydraulics for tilt, offset or side shift.
  
• Mounting via 3-point hitch; PTO shaft connection; adequate guards and safety shields.
  
• Recommended tractor horsepower often between ~30-55 HP depending on size of mower for efficient operation.
  

• Confirm mower’s required PTO speed is 540 RPM (MF135’s PTO).
  
• Ensure 3-point hitch category matches mower’s hitch (Category I or II).
  
• Check rear lift capacity: mower’s weight plus any roller, guards, etc. must not exceed MF135’s rear hitch lift limit (~1,300-1,400 kg in many versions).
  
• Check mower gearbox size, driveline length, and safety shields.
  

• Position the tractor on level ground and engage parking brake.
  
• Lower the 3-point hitch to its lowest position.
  
• Attach lower hitch arms from MF135 to mower’s lower hitch points; insert lower pins and secure with lynch pins.
  
• Attach top link from MF135 to mower’s upper hitch point (floating or fixed depending on mower) and secure. Adjust top link length to help the mower’s cutting head be slightly tilted if required (often a small angle with back lower than front to help cut and debris discharge). Manuals often recommend ~15° lower rear relative to front.
  

• Measure and if necessary adjust driveline to correct length; inner and outer sliding sections should overlap sufficiently (often at least half the travel) to avoid over-extension or collapse.
  
• Attach PTO shaft from mower to tractor output, secure locking pins / collars.
  
• Ensure PTO driveline shield is in place and chain the shield (if required) so it does not rotate or slide off.
  

• If mower has hydraulic tilt or side offset, you may need to route hydraulic hoses from MF135’s hydraulic spool or “auxiliary” function (if equipped). Some field reports recommend using a multi-spool valve or portable hydraulic control to feed the mower’s side-shift or tilt cylinder(s).
  
• Check hose sizes, fittings; adapter fittings may be needed if mower uses metric pipes and tractor uses imperial or different coupling standard.
  

• Adjust side skids or rollers to set desired cutting height; many verge mowers allow skids front and rear side to be adjusted.
  
• Roller at rear may control cutting height, so ensure mower floats or rests on roller when lowered, so roller tracks ground.
  
• Set cutting height appropriate to vegetation type; for example, light grass may be cut around 30-80 mm; heavier brush may require higher first pass.
  

• Start PTO slowly; engage with mower lowered half (not fully raised) to avoid shock loads.
  
• Use low ground speed to start; allow rotor to reach full RPM, then adjust pace.
  
• Clear area of debris (rocks, sticks) to avoid thrown objects.
  
• Ensure guards and shields are correct and intact.
  
• Disengage PTO before raising mower to transport, performing maintenance, or before detachment.
  

• Hitch mismatch (Category difference) → Use adapter brackets or aftermarket hitch kits to convert or fit properly
  
• PTO driveline too short or long → Use sliding driveline sections, ensure enough overlap, trim guards if needed
  
• Track or ground contour irregular, resulting in uneven cuts → Use float function on lift/tilt, adjust skids or rollers to follow ground
  
• Hydraulic fittings mismatch → Obtain adapter fittings and verify inside/outside diameter of tubes and hoses
  
• Overload on small MF135 when mower width or vegetation is heavy → Use a smaller mower width, make multiple passes, and avoid exceeding tractor capacity
  

• MF135 rated PTO is about 37-38 horsepower. If mower demand exceeds that, especially in heavy brush or with a wide mower, the tractor will struggle.
  
• Rear lift capacity is approximately 2,850-3,150 lbs (about 1,270-1,430 kg). The mower, roller, and additional weight must stay below this limit.
  
• Typical verge flail mower cut width is 1.3-1.5 meters. Choosing too wide a model increases required horsepower and can overload the tractor.
  

The John Deere 375 skid steer loader represents one of the company’s earlier compact loaders designed for light to medium duty applications. Introduced in the late 1980s, it was intended to provide contractors, farmers, and landscapers with a reliable machine that could maneuver in tight spaces while offering enough hydraulic power to operate a wide variety of attachments. Despite being discontinued decades ago, the 375 still circulates in the used equipment market, often praised for its durability but also criticized for limitations compared to modern skid steers.
Development Background
John Deere began producing skid steer loaders in the mid-1970s after recognizing the growing demand for compact loaders in agriculture and construction. The 375 was launched as part of the 300 series, following the 170 and 270 models, and it filled a niche for operators who wanted a simple, straightforward machine without excessive electronics. With its release, Deere was competing directly with Bobcat, Case, and New Holland—brands that had already established a foothold in the skid steer market.
The 375 remained in production until the mid-1990s, by which time Deere shifted toward higher horsepower, more refined models. During its production run, thousands were sold worldwide, with a large concentration in North America, particularly in farming states and small construction firms.
Technical Specifications

• Operating weight: around 4,000 lbs
  
• Engine: Onan gasoline engine, approximately 23–25 horsepower
  
• Hydraulic system: Open center, 7–8 gallons per minute standard flow
  
• Lift capacity: Roughly 750–850 lbs rated operating capacity
  
• Transmission: Hydrostatic drive, twin-lever control
  
• Tires: 8.50–15 standard industrial tread
  
• Dimensions: Narrow frame, approximately 54 inches wide
  

• Change hydraulic fluid every 500 hours to prevent pump wear
  
• Inspect and grease pivot points weekly
  
• Monitor tire pressure to ensure stability, as the narrow wheelbase increases rollover risk
  
• Replace worn seatbelts and consider aftermarket safety upgrades
  

Machine Overview and History
The Caterpillar D5H is part of Caterpillar’s elevated-sprocket “H-Series” of medium bulldozers, with production roughly between 1985 and 1996. It uses a 7.0 L, 4-cylinder diesel engine producing about 129–132 gross horsepower (≈96–100 kW), and roughly 120 net HP (≈90 kW) depending on year and condition.  The D5H was designed with improved durability via the elevated drive sprocket design, better undercarriage life, and improved operator comfort.
The D5H features a hydraulic system with about 18.5 gallons (≈70 L) of hydraulic oil, pump flow around 28.7 gallons per minute (≈108.6 L/min), and hydraulic pressures up to ~3,000 psi (≈207 bar).  It also has a 12-volt electrical system with a 50-amp alternator in many models.
What the Dash Lights Mean (Terminology & Functions)
The dash—specifically the EMS (Engine Monitoring System) or instrument panel—uses a set of indicator lights (warning or alert lamps). Understanding each light helps diagnose issues. Terms to know:

• EMS Panel: Engine Monitoring System; panel with lamps for various engine, transmission, hydraulic and electrical conditions.
  
• Bake-off test / Panel Test Switch: a switch that checks whether all dash lights are functional by lighting them momentarily.
  
• Sending units / sensors: devices that send electrical signals based on engine temp, oil pressure, etc.
  
• Ground / power circuits: electrical wiring that supplies power (positive) and ground (negative) to lamps and sensors.
  

• The EMS panel has two vertical columns, each with five lights. However, only certain lights are active or meaningful during normal operation.
  
• On the Left-Hand (LH) column, the functional/important lights are:
  • Top: Coolant temperature warning
  • Center: Engine oil pressure warning
  • Bottom: Hydraulic oil temperature warning
  
• On the Right-Hand (RH) column, the key ones are:
  • Top: Power train oil temperature warning
  • Center: Alternator charge warning
  • Bottom: Power train oil filter warning
  

• Some warning lights stay lit even when conditions are nominal (e.g. hydraulic oil temp high when engine is cold). This suggests either faulty sensors, incorrect wiring, or bad ground.
  
• Lights like the “check alternator” remain on despite having replaced or repaired the alternator, pointing to wiring, fuse or grounding issues.
  
• Broken wires, blown fuses, or corroded connectors are frequent culprits.
  

1. Battery & Charging System Check
   • Verify battery voltage with engine off and with engine running.
     
   • Inspect alternator output; ensure proper belt tension.
     
2. Fuse / Relay Inspection
   • Find all relevant fuses for EMS, dash lights, sensors. Replace any blown ones.
     
3. Wiring and Connections
   • Inspect wiring harnesses behind dash for breaks, chafing, corrosion.
     
   • Check connector pins; clean contacts.
     
4. Grounding Points
   • Locate known ground points for dash and sensor circuits; clean and ensure tight connections.
     
5. Sensor / Sending Unit Testing
   • For any warning that seems erroneous (engine oil pressure, coolant temp, etc.), test the corresponding sensor: remove it, inspect, measure resistance / output.
     
6. Panel Test Switch
   • Use the “panel test / lamp test” switch (if equipped) to light all lamps. If some lamps do not light during test, likely they are burnt out, lack proper power or have broken wiring.
     
7. Swap Known Good Parts
   • If possible, swap a sensor, lamp, or ground wire with a known good one to see if the issue follows the wiring or stays.
     
8. Check for Fault Codes
   • Though older D5H models may not have modern ECUs, check whether there are any legacy systems (or manual codes) indicating sensor faults.
     

• Replacing faulty sensors (oil pressure, coolant temperature, alternator output).
  
• Repairing or replacing wiring harness sections found damaged.
  
• Ensuring all ground connections are clean, tight, and free of corrosion.
  
• Replacing burned-out or non-functioning light bulbs / bulbs in lamp assemblies.
  
• Replacing fuses, or fuse holders if connections are loose or corroded.
  
• If power source to dash is weak (due to battery or alternator), resolve charging or supply issues.
  

• Hydraulic system pressure: ~3,000 psi (≈206.8 bar)
  
• Hydraulic pump flow: ~28.7 gpm (≈108.6 L/min)
  
• Electrical system: 12 V battery, 50 A alternator
  
• Operating weight: between ~21,900 lb to ~27,500 lb depending on version and attachments (≈9,900 kg to 12,500 kg)
  

• Schedule clean-ups of electrical connectors, especially in cab and around engine.
  
• Use dielectric grease on connectors after cleaning to prevent corrosion.
  
• Check fuses regularly, especially after hard use, vibration, or moisture exposure.
  
• Include ground connections in routine inspection.
  
• Use the panel test switch periodically to ensure lights and lamps are functional.
  

The MX35 and Its Compact Excavator Heritage
The Mitsubishi MX35 mini excavator was part of Mitsubishi’s push into compact construction equipment during the 1990s. Designed for tight urban job sites and utility trenching, the MX35 featured a zero-tail swing design, a hydraulic quick coupler, and a robust undercarriage. With an operating weight around 3.5 metric tons and a dig depth exceeding 10 feet, it competed with models from Kubota, Yanmar, and Komatsu. Mitsubishi Heavy Industries, founded in 1884, had long been a leader in industrial machinery, and the MX series reflected their engineering pedigree.
Though production of the MX35 has ceased, many units remain in service globally, especially in Asia and the Pacific. Their longevity is owed to simple hydraulics, durable steel construction, and widespread parts interchangeability. However, one of the most critical components—the final drive motor—can pose challenges when replacement is needed.
Final Drive Motor Function and Anatomy
The final drive motor is a hydraulic component that powers the tracks of the excavator. It converts pressurized fluid into rotational motion, driving the sprockets that move the tracks. In the MX35, the final drive motor is a two-speed axial piston motor integrated with a planetary gear reduction system.
Terminology annotation:
- Final drive motor: A hydraulic motor that powers the track system of an excavator, converting fluid pressure into torque.
- Planetary gear: A gear system that multiplies torque through a central sun gear surrounded by planet gears and a ring gear.
- Axial piston motor: A hydraulic motor that uses pistons arranged parallel to the drive shaft to generate rotational force.
- Two-speed travel: A feature allowing the operator to switch between high-speed travel and low-speed torque modes.
In the MX35, the final drive motor is typically a Nachi PH300 unit. This motor includes internal seals, bearings, and a brake assembly. Over time, seals degrade, bearings wear, and internal leakage can reduce torque or cause complete failure.
Replacement Challenges and Obsolescence
One of the main issues with the MX35 is that the original Nachi PH300 motor is no longer supported by the manufacturer. Nachi has phased out many older models, making parts difficult to source. Even well-stocked hydraulic shops struggle to find seal kits or bearing replacements for this unit.
Options for replacement include:

• Purchasing a new aftermarket final drive motor compatible with the MX35
  
• Retrofitting a similar motor from another brand with matching flange and port dimensions
  
• Rebuilding the existing motor if planetary gears and housing are intact
  
• Sourcing used motors from salvage yards or decommissioned machines
  

• Spline count and shaft diameter match the sprocket hub
  
• Bolt hole pattern aligns with the track frame
  
• Hydraulic port size and thread type match existing hoses
  
• Flow rate and pressure ratings are compatible with the MX35’s hydraulic system
  

• Safely lift and support the machine with cribbing or jack stands
  
• Remove track and sprocket to access the motor flange
  
• Disconnect hydraulic lines and cap them to prevent contamination
  
• Unbolt the motor and inspect the mounting surface for wear or debris
  
• Install the new motor, torque bolts to spec, and reconnect hoses
  
• Bleed air from the system by cycling the travel function slowly
  

• Change hydraulic fluid every 500 hours and inspect for contamination
  
• Use magnetic drain plugs to monitor for metal debris
  
• Avoid high-speed travel on rocky terrain to reduce shock loads
  
• Grease sprocket hubs and inspect track tension weekly
  
• Monitor for signs of leakage, noise, or reduced travel speed
  

Overview of the Case 850D
The Case 850D is a crawler (tracked) dozer made by Case (later Case Corporation / Case Construction), built roughly in the 1980s–early 1990s. It uses a Cummins 6-590 or 6T-590 diesel engine, putting out about 82 net horsepower (≈90 gross HP).  The machine weighs around 17,158 lbs (≈7,785 kg), with operating dimensions of about 13 ft 1 in long, 8 ft 6 in wide, and 8 ft 10 in high.  It has a power-shift transmission, 4 forward and 4 reverse speeds in many spec sheets.
Built to be rugged and reliable for grading, push work, etc., the 850D has a following among farmers, landowners, and contractors who value simplicity and parts availability. Common attachments include 6-way blade setups, and “long track” variants give better ground contact (better flotation, less ground pressure) useful on soft or uneven ground.
What to Check Before Buying / Testing
If you’re looking at purchasing one or putting a used 850D through its paces, especially a “Longtrack” version (longer tracks / longer undercarriage), here are tests and inspections to perform, direct from operator experience and common problem areas.

• Battery / Electrical System — Check battery condition and voltage. Corrosion on terminals, or rodents chewing wiring under the dash are surprisingly common issues. Pull back panels and inspect wiring where it enters control levers or pedal stations.
  
• Safety Levers / Controls in Neutral — Many owners report that the unit will not start, or starter push buttons do nothing, when safety interlocks aren’t engaged. Make sure that the steering/gearing levers are in neutral.
  
• Throttle / Engine Run Test — Set throttle mid-range (to allow some revs but not wide open) when testing. Listen for smoke, odd noises, check oil pressure, leaks. A machine that “runs strong with no hesitation,” clean exhaust and good oil pressure is a big plus.
  
• Transmission / Drivetrain Movement — After starting, test forward and reverse. Pay attention if the machine feels like it’s in neutral when you expect torque. It may be sluggish when cold, or the hydraulic / transmission fluid may be low or have been poorly maintained.
  
• Undercarriage Condition — Check track shoes (pads), rollers, idlers, sprockets. Look for:
  • Roller looseness (“sloppy rollers”) or worn bearings.
  • Tracks that are too loose or too tight.
  • Sprocket wear (flat spots, worn peaks or ‘valleys’) and bushing shape (ovalizing = “egg-shaped”).
  
• Brakes / Turning Ability — Many “850” operators warn that the braking / turning system (including master and slave cylinders, hydraulic or pneumatic depending on configuration) tends to be weaker or a problem point. Test turning in both directions; notice hesitancy, slipping, or difference between right and left tracks. Check for fluid leaks.
  
• Transmission Warm-Up Behavior — Some machines will not move until the transmission / fluids warm up. Cold weather or cold fluids can reduce hydraulic or hydraulic-related driveline performance. If it runs poorly until warm, that may indicate filters (suction, safety, bypass filters) are dirty or partially blocked.
  
• Master / Dowel Pins in Track Chain — The “longtrack” versions sometimes use master pin or ‘alligator’ (bolt-on pad) track links. These require inspection for correct assembly, whether master pins are in place, whether track links are reversed or incorrectly installed. A mis-installed or backward pin can cause issues, especially when taking the track apart for maintenance.
  

• “Machine won’t move / feels neutral” — Causes include low transmission fluid, cold/hardened fluid, blocked filters, stuck modulator valve spool. One owner disassembled the modulater valve, cleaned it, polished the bore and spool with fine grade paper, reassembled, and got normal movement restored.
  
• Uneven turning or one side weak — Could be brake fluid loss, master or slave cylinder issues, hydraulic leaks. Inspect each side individually, check pedal response, and check the linkage to the braking or steering clutches.
  
• Sloppy or noisy undercarriage components — Rollers, idlers, bushings wear with time. Replacing worn rollers / bearings, replacing pad bolts, adjusting chain tension can lengthen life.
  
• Track separation / idler issues — Front idlers may get hot, noise may develop (dragging drag-braake-like sound), resistance in turning or moving. Depending on condition, some choose to replace the whole idler assembly rather than individual bearings, especially on older machines where sealing and alignment may be compromised. Master pin or alligator style track links factor into whether track separation tools are needed.
  

1. Pre-Start Visual Check
   • Inspect battery, fluid levels (engine oil, coolant, transmission and hydraulic fluid)
     
   • Look for leaks, rust, broken or loose components
     
2. Electrical / Ignition Check
   • Key “on” – check for dash lights, indicators
     
   • Ensure safety levers / neutral locks are in the proper positions
     
3. Start Engine
   • Let idle, check for smooth running, smoke check, listen for knocking or rattling
     
   • Warm-up sufficiently to operating temperature
     
4. Transmission / Movement Test
   • Drive forward / reverse, test stationary turning (using hi-low range or torque convertor input)
     
   • Note lag, slipping, strange sounds
     
5. Blade / Attachment Check
   • If a 6-way blade is installed, test lift, tilt, side shift, look for leaks in blade cylinders
     
6. Undercarriage Inspection while Moving
   • Observe track tension, ride quality, sound of idlers, rollers
     
7. Brake / Turn Responsiveness
   • Test turning both directions under low and moderate speeds
     
8. After Shutdown
   • While engine is still warm, check fluid sampling (engine oil, transmission oil may show metallic particles)
     
   • Inspect undercarriage for wear revealed under load
     

• Change engine oil & filter every 200-300 hours under normal use; under harsh conditions maybe every 200.
  
• Transmission & final drive fluids: consider changing every 500 hours (depending on use and condition).
  
• Track & roller grease / lubrication: weekly or every work shift depending on mud/sand exposure.
  
• Cooling system: flush annually or more often if in dusty or dirty conditions.
  

• Net power ~ 82 HP at ~2,000 rpm.
  
• Max torque ~ 253 lb-ft at ~1,500 rpm.
  
• Fuel capacity ~ 40 gallons.
  

• One owner related that after sitting overnight in cold weather, their 850D would not move at all until warmed up for 10-15 minutes. The culprit turned out to be a clogged suction screen in the transmission pump. Once cleared, even cold starts moved almost immediately.
  
• Another recounts that uneven braking (strong on one side, weak on the other) caused by a failed slave cylinder led to poor turning. Fixing that allowed much better maneuverability, especially on slopes.
  
• In a sale listing, an 1987 Case 850D with about 4,420 hours and open-cab, with “only ~50 hours on the undercarriage since overhaul,” was priced around US$35,000. Machine condition graded fairly high (4/5) and included Berco oil-filled track chains. This shows the potential value of units with rebuilt or minimally worn undercarriage.
  

• Check that engine, transmission, and undercarriage are sound before making major investment.
  
• Factor in the cost of undercarriage wear: track shoes, rollers and idlers tend to be among the costliest items.
  
• Know how to operate the specialized controls (high/low range levers, forward/reverse, foot pedals) to avoid damaging parts by misuse.
  
• Make sure any dozer you buy has been properly maintained: filtration, fluid condition, cooling systems.
  

Machine Context and Importance of the Swing Motor
Excavators, including mid-sized models used in construction, forestry, and landscaping, rely on a swing motor (also called a swing drive or slew motor) to rotate the upper structure. This component integrates a hydraulic motor, gear reduction set (planetary or bevel gears), and a slew ring bearing. If this assembly becomes obstructed by leaves, brush, or other debris, it can suffer from reduced service life, heat buildup, seal failures, or even total swing failure. Heavy-duty models in dusty or forested areas report up to 20-40 % shortened swing motor lifespan when debris ingress is ignored.
Why Cleanliness Matters

• Leaves and brush trap moisture, which can promote corrosion on metal flanges, bolts, and seals.
  
• Organic material holds dirt and grit, which acts as abrasive wear particles once moisture and vibration cause loosening.
  
• Obstructions can interfere with heat dissipation, overloading motor cooling, causing internal overheating.
  
• Debris build-up may block lubrication or grease access in swing bearing cavities, increasing friction and accelerating wear.
  

• Swing motor / swing drive: the hydraulic motor + gearbox that enables rotation of the house.
  
• Slew ring / swing bearing: the large bearing allowing upper structure rotation.
  
• Seal: component that prevents oil ingress/outgress.
  
• Heat soak / thermal stress: temperature build-up from obstructed cooling.
  

• Machines operating near trees, dense brush, or during autumn leaf fall are at highest risk.
  
• Wet conditions (rain, dew) worsen moisture retention under debris.
  
• Windy or stormy weather pushes organic debris into tight swing motor clearances.
  
• Jobsites where maintenance is infrequent—monthly or less—show significantly more buildup.
  

1. Manual removal
   • Use stiff brushes or plastic scrapers to lift leaves, twigs, and moss.
     
   • Remove from gaps between motor housing, slew ring seals, flanges, and guard plates.
     
2. Low-pressure air blowers
   • Blast air at ~20-40 psi to lift light organic debris without driving dirt into seals.
     
   • Best done with machine off and surfaces cooled.
     
3. Vacuum tools
   • Industrial wet/dry vacuums catch debris without scattering.
     
   • Particularly useful where leaves are wet or packed.
     
4. Pressure washing with caution
   • If used, keep water jet more than ~30 cm away from seal edges and motor casing.
     
   • Use mild pressure (<1000 psi) and avoid direct spray into joints and bolt holes.
     
5. Protective shielding
   • Install debris guards, mesh screens, or deflectors above swing motor.
     
   • Over time, retrofit kits have become more common; some manufacturers offer guards to reduce debris ingress by up to 60 %.
     

• Clean around swing motor daily in high-debris locations; in cleaner sites, every shift or at least weekly.
  
• Inspect seals and bearing cavity grease every 100–250 operating hours.
  
• Grease slew ring bearing as per manufacturer spec—often every 200-500 hours depending on load and conditions.
  
• Thorough cleaning and lubrication before wet seasons or after logging operations.
  

• Park on level surface, secure machine, and shut off engine.
  
• Let swing motor area cool, remove guards or covers if possible.
  
• Brush and vacuum debris.
  
• Blow remaining dust away with compressed air.
  
• Wipe surfaces with a non-corrosive cleaner; check for moisture under seals.
  
• Reapply grease to swing bearing; torque bolts to spec.
  
• Inspect all bolts, flanges, and protective guards for tightness and damage.
  

• Using high-pressure washers too close to seals, forcing water in.
  
• Neglecting to protect motors during seasonal leaf fall.
  
• Overlooking small debris under bolt heads or around breather vents.
  
• Using wrong type of grease that either washes away or absorbs moisture.
  

• Reduced thermal stress leads to better seal life and fewer hydraulic leaks.
  
• Lower incidence of swing bearing damage or wear.
  
• Less downtime—machines remain operable, fewer emergency repairs.
  
• Energy savings—less hydraulic power wasted overcoming friction, lower fuel usage.
  

Understanding SSR Drift and Alignment Challenges
Smooth drum rollers (SSR), especially single-drum vibratory models, are designed for linear compaction of soil, gravel, and asphalt. However, operators occasionally report a phenomenon known as “side walking” or lateral drift—where the machine veers off its intended path during forward travel. This behavior can compromise compaction uniformity, increase operator fatigue, and pose safety risks on slopes or near curbs.
Terminology annotation:
- SSR (Smooth Drum Roller): A compaction machine with a cylindrical steel drum used to compress surfaces through static weight and vibration.
- Side walking: Unintended lateral movement of the roller during straight-line travel, often caused by mechanical imbalance or terrain factors.
- Drum offset: A design feature where the drum is positioned slightly off-center to improve edge compaction.
- Articulated steering: A steering system where the front and rear frames pivot relative to each other, allowing tighter turns and better maneuverability.
Mechanical Causes of Lateral Drift
Several mechanical factors can contribute to side walking in SSRs:

• Uneven tire pressure or wear on the rear wheels
  
• Misalignment in the articulation joint or steering cylinders
  
• Drum mounting offset or asymmetrical frame geometry
  
• Worn bushings or pivot pins in the articulation system
  
• Hydraulic imbalance between left and right drive motors
  

• Check and equalize tire pressure on both rear wheels
  
• Inspect articulation pins and bushings for excessive play
  
• Measure drum offset and verify against manufacturer specs
  
• Test hydraulic flow rates to each drive motor for imbalance
  
• Realign steering cylinders and recalibrate control valves if needed
  

• Operate on level ground when diagnosing drift behavior
  
• Use consistent steering input and avoid overcorrection
  
• Monitor drum contact pattern for uneven compaction marks
  
• Adjust travel speed to reduce vibration-induced drift
  

• Hamm and Dynapac often use symmetrical drum placement with center articulation
  
• Caterpillar and Volvo may use slight drum offset for visibility and edge coverage
  
• Sakai and Bomag offer models with split drums or dual amplitude settings that affect drift
  

• Inspect articulation joints every 500 hours
  
• Check tire wear and pressure weekly
  
• Monitor drum mounting bolts and bushings for play
  
• Calibrate steering controls annually
  
• Test hydraulic flow balance during scheduled service
  

The Challenge of Cold Weather Operation
Operating a skid steer in freezing conditions can quickly turn from productive to punishing if the cab is not properly heated. Many skid steer operators, especially those using older machines like the John Deere 317, have faced the dilemma of whether to retrofit a cab heater. The 317, first introduced in the mid-2000s, was part of Deere’s mid-sized skid steer lineup. It gained popularity for its balance of maneuverability and strength, with more than 10,000 units sold during its production run. However, unlike modern models that often come with factory-installed heating and air conditioning, many 317 units were delivered as open-cab or with only minimal heating provisions.
Factory Options Versus Aftermarket Solutions
John Deere offered optional cab enclosures and HVAC packages, but many machines on the used market lack these. Retrofitting an OEM-style heating system can be expensive, requiring ductwork, blower fans, and a coolant-fed heater core. For budget-conscious owners, aftermarket heaters designed for compact equipment or agricultural tractors have become popular alternatives. These units generally consist of a compact heater core with a 12V fan, connected to the engine’s coolant system. Warm coolant circulates through the heater, and the fan pushes heated air into the cab.
Technical Considerations Before Installation

1. Coolant Access Points – The 317’s Yanmar diesel engine allows for tapping into the heater circuit using the lines feeding the engine block. One hose can be connected at a point near the thermostat housing, while the return can be routed to the water pump inlet. Ensuring correct flow direction is essential, as reversing the hoses can drastically reduce heat output.
   
2. Cab Sealing – Without proper sealing, even the best heater cannot keep the operator warm. Installing weatherstripping around the doors and windows, sealing floor plates, and covering unused openings can reduce cold air infiltration by up to 40%.
   
3. Electrical Load – Aftermarket heaters typically use a 12V blower that consumes between 5 and 12 amps. The John Deere 317 is equipped with a 55-amp alternator, which generally provides enough overhead capacity, but machines running multiple accessories (lights, radios, auxiliary electronics) should verify total draw to prevent battery drain.
   
4. Mounting Location – The most common location is under the seat or in a corner of the cab, where ducting can be directed toward both the operator and the windshield. Some operators fabricate brackets to mount the unit overhead, though this requires more extensive modification.
   

• Drain a portion of the coolant to prevent spillage when cutting into the system.
  
• Use reinforced heater hose rated for high temperature, usually 5/8-inch inner diameter.
  
• Secure hoses with clamps and route them away from moving parts or sharp edges.
  
• Install shutoff valves on the heater lines, allowing the operator to disable coolant flow in summer months.
  
• Mount the heater securely, ensuring that vibration does not loosen the unit during operation.
  

• For owners in cold climates, a properly installed cab heater in a John Deere 317 is a worthwhile upgrade.
  
• Ensure the cooling system is in good health before installation, as heater performance depends on coolant flow and engine temperature.
  
• Invest time in sealing the cab to maximize heating efficiency.
  
• Consider auxiliary electrical upgrades if additional accessories are in use.