DO-MOR Company Background
DO-MOR Manufacturing is an established American company specializing in producing high-quality undercarriage and heavy machinery parts. Founded in the mid-20th century, the company has supplied components for bulldozers, excavators, and other construction equipment globally. Their reputation is built on durability, precision engineering, and competitive pricing. DO-MOR’s products are compatible with brands such as Caterpillar, Komatsu, Case, John Deere, and Hitachi, making them a preferred choice for contractors who need reliable replacement parts.
Product Range and Applications
DO-MOR produces a wide array of components for heavy equipment, including:

• Track chains and track shoes for excavators and bulldozers
  
• Rollers, idlers, and sprockets
  
• Hydraulic components such as cylinders and hoses
  
• Engine and transmission parts for older equipment models
  
• Wear parts for loaders, skid steers, and backhoes
  

• Exact Model Fit: Verify compatibility with your equipment model and year, as small variances in undercarriage dimensions can affect fit and function.
  
• Quality Checks: Inspect parts for casting or machining defects before installation.
  
• Lubrication and Torque: Follow recommended torque specifications for bolts and proper lubrication to prevent premature wear.
  
• Maintenance Schedule: Incorporate DO-MOR parts into regular maintenance cycles, as consistent inspections and adjustments improve longevity.
  

• Cost-effectiveness compared to OEM parts, sometimes saving 20–40%
  
• Wide availability for multiple equipment brands and older models
  
• Durable construction suitable for demanding applications
  
• High compatibility with aftermarket refurbishing programs for tracked equipment
  

• Always cross-check the equipment serial number with the DO-MOR part number
  
• Maintain detailed service logs to track performance and wear
  
• Rotate track shoes periodically to balance wear and extend undercarriage life
  
• Combine DO-MOR parts with preventive maintenance practices to reduce unexpected downtime
  

The CAT D3 and Its Undercarriage Evolution
The Caterpillar D3 dozer, introduced in the early 1970s, was designed as a compact crawler for light to medium-duty earthmoving. It quickly gained popularity for its maneuverability, reliability, and ease of maintenance. The D3’s undercarriage system, particularly in early models, featured segmented sprockets bolted around a hub or final drive flange. This design allowed for easier replacement of worn sprocket teeth without removing the entire final drive assembly.
Caterpillar, founded in 1925, has long been a leader in track-type tractors. The D3 series has undergone several iterations, with the original models using mechanical steering clutches and later versions adopting hydrostatic transmissions. Despite these changes, the segmented sprocket design has remained a staple in many of their small to mid-size dozers.
Understanding the Sprocket Segment and Flange Interface
On older D3 models, the sprocket is not a single cast piece but rather a set of segments—typically six—that bolt onto a circular flange surrounding the final drive hub. These segments are precision-machined to interlock and form a continuous ring of teeth that engage the track chain.
When replacing worn sprocket teeth, the segments must be aligned and torqued properly to ensure:

• Even load distribution across the flange
  
• Prevention of bolt loosening due to vibration
  
• Proper meshing with the track chain to avoid premature wear
  

• Clean the flange surface thoroughly, removing rust, grease, and debris
  
• Inspect the bolt holes for elongation or thread damage
  
• Apply anti-seize compound to the bolts to prevent galling
  
• Position the segments in sequence, ensuring the mating surfaces align flush
  
• Use a torque wrench to tighten bolts in a star pattern, gradually increasing torque in stages
  

• First pass: 80 ft-lbs
  
• Second pass: 150 ft-lbs
  
• Final pass: 220 ft-lbs
  

• Always use new Grade 8 bolts and hardened washers
  
• Verify torque specs from the service manual specific to your serial number
  
• Recheck bolt torque after 10–20 hours of operation
  
• Monitor for signs of loosening, such as oil seepage or metallic noise
  

Komatsu PC200 LC-8 Overview
The Komatsu PC200 LC-8 is a mid-sized hydraulic excavator widely used in construction, mining, and heavy civil works. Introduced in the mid-2000s as part of Komatsu’s PC200 series, it replaced the PC200 LC-7 with enhanced hydraulic efficiency, improved operator ergonomics, and stronger structural components. The machine’s rated operating weight is officially listed around 45,000 lbs (20,400 kg), with a standard bucket capacity of 1.0 m³ for general-purpose digging. Over its production run, Komatsu sold tens of thousands worldwide, establishing the PC200 LC series as a workhorse in both developed and emerging markets.
Reported Weight Discrepancy
Several operators have reported that the actual in-field weight of their PC200 LC-8 can exceed the manufacturer’s listed figure by as much as 3,000 lbs (1,360 kg). This discrepancy is often influenced by:

• Additional Attachments: Hydraulic thumbs, quick couplers, or reinforced buckets increase weight beyond OEM specifications.
  
• Fuel Load: A full fuel tank adds roughly 200–300 lbs, which contributes to overall weight.
  
• Hydraulic Fluids and Coolants: Fully topped-off hydraulic oil and engine coolant can account for 400–600 lbs extra.
  
• Track and Undercarriage Wear: Replacement steel tracks or track shoe extensions can add significant mass.
  
• Optional Counterweights: Some units shipped with extra counterweights for lifting heavy loads or stabilizing excavators on uneven terrain.
  

• Transportation Limits: Overweight equipment may violate legal road limits, requiring special permits or trailers rated for higher loads.
  
• Lift Capacity: Exceeding weight limits can reduce the safe lifting capacity of the boom and arm, altering stability calculations.
  
• Ground Pressure: Extra weight increases ground pressure, potentially causing soil compaction or reducing mobility in soft conditions.
  
• Fuel Efficiency: Heavier machines consume more fuel per operating hour, impacting operating costs over the machine’s lifespan.
  

• Weigh Machines Accurately: Use certified scales at equipment yards to measure exact weight, including attachments and fluids.
  
• Adjust Counterweights: If possible, remove unnecessary counterweights when not performing heavy-lift tasks.
  
• Monitor Lift Charts: Recalculate boom and arm lift capacities with the actual operational weight for safety compliance.
  
• Plan Transport Carefully: Use transport trailers rated above the measured gross weight to ensure safe over-road movements.
  
• Track Wear Management: Maintain or replace worn track shoes with lighter alternatives when heavy attachments are frequently mounted.
  

The CAT 963B and Its Undercarriage Design
The Caterpillar 963B track loader was introduced in the late 1980s as part of Caterpillar’s evolution of mid-size crawler loaders. With an operating weight around 38,000 pounds and a 150-horsepower engine, the 963B was built for versatility in construction, demolition, and material handling. Its undercarriage features a grease-filled track tensioning system, which uses hydraulic pressure to extend the idler and maintain proper track tension.
The 9BL serial prefix identifies a specific production series of the 963B, often associated with units built in the early 1990s. These machines are known for their durability but require precise maintenance, especially in the track tensioning assembly.
Symptoms of Track Tension Loss
Operators may notice that after pumping grease into the tensioner, the track holds tension briefly but then slowly relaxes when the machine moves. This behavior suggests a leak in the tensioning system, which can originate from several points:

• Rod seal failure: Allows grease to escape around the piston rod
  
• Grease valve leakage: A faulty valve can bleed pressure back into the reservoir
  
• Barrel damage: Rust pits or worn chrome inside the barrel compromise sealing surfaces
  
• O-ring failure: Internal seals near the valve may degrade or roll during installation
  

• Lubricate the barrel with silicone-based grease or hydraulic fluid, not WD-40, which can degrade rubber over time
  
• Use seal installation tools to prevent rolling or twisting during insertion
  
• Inspect the seal orientation—some seals are directional and must face the pressure side
  
• Warm the seal slightly to improve flexibility and seating
  

• Pump grease and monitor pressure drop over time
  
• Remove the valve and inspect the O-ring (often item 14 in diagrams)
  
• Replace with OEM-grade seals, as generic O-rings may not withstand the pressure or temperature range
  

• Inspect tension cylinders every 500 hours
  
• Replace seals proactively during track service
  
• Avoid over-pumping grease, which can damage seals or cause hydraulic lock
  
• Use high-quality grease rated for heavy equipment
  
• Keep the barrel clean and dry during installation to prevent contamination
  

What Is a Hydraulic Diverter Kit
A hydraulic diverter (or “third-function”) kit allows you to redirect hydraulic flow from a tractor or backhoe’s existing auxiliary circuit to drive an additional implement—such as a grapple, auger, or hydraulic thumb—without interfering with the primary loader or backhoe functions. This capability is especially useful on a John Deere 310SG backhoe loader, because it adds versatility by giving you a dedicated output for attachments, enabling dual‑circuit control.
Why Install One on a 310SG
The John Deere 310SG is a versatile backhoe loader used in construction, landscaping, and heavy‑dirt work. While the machine already offers dedicated hydraulic circuits for the loader and backhoe, a diverter kit unlocks the ability to run a third function:

• Operate a hydraulic thumb to pick up brush, debris, or irregular objects
  
• Use an auger for drilling post holes without constant manual connections
  
• Employ a grapple for clearing and loading tasks
  
• Run a breaker or rock hammer without tying up existing circuits
  

• Selector/Diverter Valve: The core of the kit. This valve directs or “diverts” hydraulic flow between two circuits—typically between a standard auxiliary and a third-function outlet.
  
• Solenoid‑Operated Valve: Many diverter kits use an electrically controlled solenoid to switch flow, allowing seamless control via a toggle switch or joystick.
  
• Flow Capacity: Measured in gallons per minute (GPM), the valve must handle your machine’s hydraulic flow rate without causing performance loss.
  

• Summit Hydraulics Diverter: A standard solenoid‑controlled diverter valve, ideal for adding a dedicated output to your JD backhoe.
  
• Summit Multiplier Selector: Premium version with built-in switch and 13 GPM capacity, good for high‑flow attachments.
  
• Summit 3rd Function Valve Kit: Complete kit including joystick handle, diverter valve, and hoses—designed for implement control.
  
• Summit Electric Diverter Kit: Adds electrical control to your diverter, allowing remote switching from the cab.
  
• Farmer Bob 2‑Circuit Hydraulic Kit: A budget-friendly solution that enables a second circuit and third function without sacrificing much flow.
  
• Summit Solenoid Selector Valve: A compact solenoid valve for diverter/splitter applications, helpful if space is tight.
  
• Universal Multiplier Splitter/Diverter: Highly flexible design, works with many machines; good if you plan to move the diverter between units.
  
• Extended Tractor Remote Diverter: Designed with a longer body to make installation easier on tight or crowded hydraulic systems.
  

• Mounting: Choose a stable point on the existing hydraulic circuit, ideally near the existing auxiliary valve.
  
• Electrical Wiring: If the kit uses a solenoid, you’ll need to run a 12V wire from a switch to the valve. Ensure the power draws are properly fused.
  
• Bleeding the System: After installation, cycle through the new valve repeatedly to remove air. Hydraulic systems with diverters can trap air more easily.
  
• Flow Balance: Some diverters may cause slight flow loss through the main auxiliary circuit; check attachment performance and adjust accordingly.
  
• Fittings and Hoses: Use high-quality hydraulic hose rated for your machine’s maximum pressure. Avoid restrictive fittings that choke flow.
  
• Maintenance: Periodically inspect the diverter valve for leaks or solenoid wear—this is a high-stress component.
  

• Increases machine versatility
  
• Saves time swapping hydraulic lines
  
• Allows use of more attachments
  
• Improves productivity
  

• Extra installation cost
  
• Slight drop in flow may occur
  
• Additional point of potential hydraulic failure
  
• Electrical and hydraulic complexity added
  

• You frequently use grapple, auger, or other hydraulically powered attachments.
  
• You want to avoid hassle of constantly disconnecting lines.
  
• Your auxiliary hydraulic circuit has spare flow capacity.
  
• You’re aiming to maximize efficiency and reduce cycle times.
  

The Cletrac and Its Role in Early Logging
Among the most iconic machines of early 20th-century logging was the Cletrac crawler tractor. Manufactured by the Cleveland Tractor Company, Cletrac machines were known for their compact design and dual-drum winch systems. These winches were often rigged to trees for yarding logs—a method where felled timber was dragged uphill using cables. The Cletrac’s rugged build and mechanical simplicity made it a favorite among small-scale “gypo” loggers during and after World War II. Operating one often required two people: a driver and a winch operator, leading to the tongue-in-cheek suggestion that a “helper monkey” was needed to manage all the controls.
The Beloit Tree Harvester Was Decades Ahead of Its Time
One of the most intriguing machines from the early mechanized logging era was the Beloit Tree Harvester, developed in the early 1960s by Bob Larson in Minnesota. This machine was a prototype feller-buncher-delimber hybrid. It would clamp onto a standing tree, use a multi-section boom to delimb it while upright, lop off the top, shear the trunk at the base, and then stack the log in a pile. This process eliminated the need for multiple machines and manual labor, streamlining the entire harvesting cycle.
Despite its innovation, the Beloit Harvester never saw widespread adoption. Its complexity, cost, and the conservative nature of the logging industry at the time likely contributed to its limited production. However, it laid the groundwork for modern feller bunchers and harvesters used today in mechanized forestry.
The McGiffert Loader and Its Influence on Tower Skidders
Another rare sight was a preserved McGiffert loader, a piece of equipment that straddled railroad tracks and loaded logs onto railcars from above. This loader was a marvel of early 20th-century engineering and is believed to have influenced the design of later tower skidders, such as those produced by Lidgerwood. These machines revolutionized steep-slope logging by allowing logs to be yarded uphill using high-lead cable systems.
Restored Crawlers and Logging Trucks at Woodland and Collier Museums
In Woodland, California, the Heidrick Agricultural History Center houses a collection of beautifully restored crawler tractors and early logging trucks. These include rare serial-numbered machines and early Fageol-built Peterbilts—trucks that predate the modern Peterbilt brand. Meanwhile, near Klamath Falls, Oregon, the Collier Memorial State Park features an outdoor logging museum with dozens of vintage machines, including the Beloit Harvester and other obscure equipment.
Visitors to these museums often marvel at the sheer size of the logs once harvested and the primitive machines used to move them. One visitor recalled seeing pine logs so massive they dwarfed the trucks hauling them—testament to the scale of old-growth logging in the Pacific Northwest.
Preservation and Historical Significance
Preserving these machines is more than a nostalgic exercise. They represent the evolution of industrial forestry and the transition from manual labor to mechanized efficiency. Each machine tells a story of innovation, risk-taking, and adaptation in one of the most dangerous industries in North America.
To support preservation efforts:

• Encourage local museums to document oral histories from retired loggers
  
• Digitize blueprints and manuals for rare machines
  
• Host vintage logging equipment shows to raise awareness
  
• Collaborate with historical societies to secure funding for restoration
  

Overview of Track Chains
Track chains are a fundamental component of tracked machinery such as excavators, bulldozers, and tracked loaders. They form the continuous loop that drives the undercarriage, allowing heavy equipment to move efficiently over rough terrain. Track chains are designed to endure extreme loads, abrasive surfaces, and continuous friction, making them critical to machine performance and longevity.
Components of a Track Chain
Track chains consist of several interconnected components:

• Track Links: The primary segments that form the continuous chain, typically made from high-strength alloy steel.
  
• Pins and Bushings: Provide articulation between links, allowing flexibility while maintaining structural integrity.
  
• Rollers: Support the machine’s weight and facilitate smooth movement over uneven ground.
  
• Shoes (Grousers): The external plates that contact the ground, offering traction and stability.
  
• Master Links: Connect the ends of the chain to form a complete loop and allow assembly/disassembly.
  

• Standard Track Chains: Designed for general construction, earthmoving, and moderate abrasive conditions.
  
• Heavy-Duty Chains: Include thicker links and reinforced pins for mining or quarry operations.
  
• Long-Track Chains: Extended undercarriage chains providing better stability on slopes or soft ground.
  
• Rubber-Encased Chains: Used in compact equipment to minimize ground damage in urban or sensitive areas.
  

• Elongation: Excessive stretching between pins and bushings reduces tension and can cause derailment.
  
• Cracked Links or Shoes: Visible fractures compromise structural integrity.
  
• Worn Pins or Bushings: Leads to increased play and accelerated wear of rollers and sprockets.
  
• Uneven Shoe Wear: Indicates misalignment or improper tensioning.
  

• Compatibility: Ensure links, pins, and shoe width match the machine specifications.
  
• Undercarriage Condition: Worn rollers, idlers, or sprockets should be replaced simultaneously to prevent rapid wear of new chains.
  
• Installation Tools: Hydraulic presses or chain breakers may be required for heavy-duty chains.
  
• Alignment: Proper tension and alignment prevent derailment and uneven wear.
  

The Bobcat 430 and Its Attachment Interface
The Bobcat 430 ZHS (Zero House Swing) is a compact excavator designed for tight-space operations, offering a maximum digging depth of approximately 10 feet and an operating weight around 8,000 pounds. Manufactured in the early 2000s, the 430 was part of Bobcat’s push into the mini-excavator market, competing with brands like Kubota and Takeuchi. One of its key features is its compatibility with various quick coupler systems, allowing operators to switch between buckets, thumbs, and specialty tools without manual pin removal.
Understanding the Wain-Roy and Tag Coupler Systems
The Wain-Roy coupler system, developed decades ago, uses a hook-and-pin design that allows for quick attachment changes. It became a de facto standard in many regions, especially in the northeastern United States. Tag Manufacturing later introduced its own coupler system, which in some cases mimics the Wain-Roy geometry but with proprietary dimensions and locking mechanisms.
The Tag QC27 coupler is a specific model designed for compact excavators like the Bobcat 430. It typically fits attachments with a matching lug spacing and pin diameter. However, not all Wain-Roy buckets or tools will fit a Tag QC27 without modification, even if they appear similar.
Challenges in Sourcing the Right Coupler
Operators seeking a replacement or new coupler for the Bobcat 430 often face several hurdles:

• Limited dealer support: Some rental yards carry Tag equipment but may not sell parts directly.
  
• Manufacturer response delays: Direct inquiries to Tag Manufacturing may go unanswered if the buyer is not a registered dealer.
  
• High shipping costs: Online retailers like Langfel may offer the correct coupler but charge excessive freight fees, especially for residential delivery.
  
• Compatibility confusion: Many used attachments are labeled “Wain-Roy style” but may not align with the QC27 geometry.
  

• Contact regional equipment dealers who specialize in compact excavators and carry Tag or Wain-Roy inventory.
  
• Reach out to equipment resellers like Phoenix Equipment, which often stock a wide range of couplers and can provide technical support.
  
• Check with national rental chains such as United Rentals, which frequently use Tag couplers and may offer surplus or used inventory.
  
• Use precise measurements of pin diameter, center-to-center spacing, and ear width to verify compatibility before purchase.
  

Understanding Excavator Types
Excavators come in multiple configurations tailored to different work requirements. The main types include:

• Mini Excavators: Compact and maneuverable, ideal for residential or urban sites. Operating weight typically ranges from 1–6 tons.
  
• Standard Excavators: Commonly used in construction and medium-scale earthmoving. Operating weight ranges from 6–30 tons.
  
• Heavy Excavators: Designed for large-scale projects, often exceeding 30 tons. Used in mining, large infrastructure, and quarrying operations.
  
• Specialty Excavators: Includes long-reach models, demolition variants, and materials-handling configurations.
  

• Operating Weight: Influences stability, ground pressure, and transport requirements.
  
• Engine Power: Measured in horsepower (HP) or kilowatts (kW); higher output improves digging force and productivity.
  
• Hydraulic Flow and Pressure: Determines attachment performance, including buckets, breakers, and grapples.
  
• Bucket Capacity: Must match material type and expected workload.
  
• Reach and Dig Depth: Essential for trenching, foundation work, or site clearing.
  

• New Machines: Come with full warranty, latest technology, and minimal downtime. High initial cost is offset by reliability and lower maintenance early in the machine’s life.
  
• Used Machines: Lower upfront cost but require detailed inspection for engine hours, hydraulic leaks, undercarriage wear, and prior repair history. Performance may vary depending on previous use and refurbishment.
  

• Engine: Check for leaks, smoke, unusual noises, and service history
  
• Hydraulics: Inspect hoses, cylinders, and pumps for wear or damage
  
• Undercarriage: Track shoes, rollers, and idlers significantly affect operational cost
  
• Electrical Systems: Ensure lights, control panels, and starter systems are functional
  
• Structural Integrity: Look for cracks or weld repairs in the boom, arm, and chassis
  

• Buckets: Standard, trenching, grading, or rock buckets
  
• Breakers: Hydraulic hammers for demolition or rock breaking
  
• Grapples: Useful for material handling, recycling, or forestry operations
  
• Augers: For drilling holes for posts, pilings, or landscaping
  

• Service network proximity
  
• Parts availability and delivery times
  
• Knowledgeable technical support
  
• Transparent pricing and documentation
  

• Transport costs for moving the machine to the job site
  
• Operator training and certification costs
  
• Fuel and regular maintenance expenses
  
• Insurance coverage and liability protection
  

Why the Conversion Matters
Many older lowboy trailers, especially 25–30 ton dual-axle models, were originally equipped with 15-inch Dayton-style tube-type wheels. These wheels often use snap ring or split rim designs, which are increasingly difficult to service due to safety concerns and declining technician familiarity. Converting to 17.5-inch tubeless wheels offers several advantages:

• Easier tire mounting and dismounting
  
• Improved safety with modern one-piece rims
  
• Better availability of tires and parts
  
• Enhanced load handling and heat dissipation
  

• The new rims match the hub’s bolt circle and pilot diameter
  
• The offset is compatible with the trailer’s axle spacing
  
• The wedges and center spacers are suitable for tubeless grip points
  

• Accuride 31868-175-PKGRY21
  
• Accuride 17575-WD
  
• Firestone 318-68175
  

• Lay the rim flat and measure from the mounting surface to the back edge
  
• Compare this to the centerline of the rim width
  
• Ensure the new offset maintains proper clearance between tires and trailer frame
  

• Higher speed ratings
  
• Better fuel efficiency
  
• Longer tread life
  
• Reduced blowout risk under heavy loads