Finding Spare-Part Numbers for Excavator Undercarriage Components — A Practical Guide

[MikePhua]

Overview
This article explains how to identify and source international spare-part numbers for common excavator undercarriage parts (track link assemblies, shoes, bolts, nuts, rollers, sprockets, idlers, guards, springs, etc.) across multiple brands and models. It turns a vague parts enquiry into a clear, step-by-step process you can apply whether you’re working on mid-size machines or older models. The guidance focuses on practical measurement, cross-referencing, vendor strategy, and quality checks, with terminology notes, suggested parameters, troubleshooting tips, and real-world examples. The original request included multiple machine model families and a list of undercarriage items.
Models and parts involved (what was asked for)

• Models referenced:
  • DX 225
    
  • E312, E320, E330
    
  • PC200, PC300
    
  • SH200
    
  • SK115, SK135, SK200, SK210, SK350
    
  • ZX200, ZX330
    
• Under/undercarriage parts requested:
  • Track Link Assembly
    
  • Track Shoe
    
  • Track Bolt
    
  • Track Nut
    
  • Top/Carrier Roller
    
  • Bottom/Road Roller
    
  • Sprocket
    
  • Idler
    
  • Roller Guard
    
  • Spring.
    

Why part numbers matter (short)

• A correct part number gives you the exact fit, heat-treatment, and dimensions OEM-specified for that machine and serial range.
  
• Different model years and serial ranges often use different part numbers even when parts look similar.
  
• Aftermarket part numbers exist, but you must confirm dimensional and material equivalence.
  

Key terminology (quick glossary)

• OEM part number — Original Equipment Manufacturer identifier; primary source of truth.
  
• Aftermarket/Equivalent number — Third-party identifier that claims compatibility.
  
• Serial number / Machine S/N — The machine’s unique ID that helps vendors map correct parts.
  
• Pitch / Link pitch — Center-to-center distance between track pins; critical for shoes, links, and sprockets.
  
• Bolt circle / Bolt pattern — Pattern of bolts on sprockets or idlers; required for bolt/washer selection.
  
• Pad width / Shoe width — Ground contact width of a track shoe; affects flotation and fit.
  

Step-by-step method to find correct part numbers

• Gather machine identity:
  • Record brand, model, exact model code, and full serial number from the data plate or frame.
    
  • Note any factory options or retrofit kits (high-drive, high-lift, long-arm, etc.).
    
• Photograph and document the part(s):
  • Take clear photos of the part, surrounding attachments, and any stamped numbers.
    
  • Photograph the mating faces and bolt patterns.
    
• Measure critical dimensions (use calipers, tape, or digital tools):
  • For track links/shoes: pitch, pin diameter, shoe width, bolt hole spacing.
    
  • For rollers/idlers: outer diameter, inner bore diameter, width, mounting hole pattern.
    
  • For sprockets: pitch, number of teeth, bolt circle diameter, thickness.
    
• Search OEM resources:
  • Use the machine S/N with OEM parts catalog or authorized dealer parts lookup to get exact part numbers.
    
• Cross-reference:
  • Compare OEM number to aftermarket catalogs and cross-reference tables when OEM supply is limited.
    
• Confirm with vendor:
  • Send S/N, photos, and measured dimensions to a parts supplier and request a written compatibility confirmation before ordering.
    
• Inspect and test on receipt:
  • Check stamping/marking on delivered parts, measure key dimensions, compare material spec if available.
    

Practical sourcing tips and vendor strategy

• Always lead with the machine serial number — it cuts search time dramatically.
  
• Where OEM is slow or back-ordered, ask for an “interchange” or “cross reference” from the supplier. Provide photos and measurements to avoid mistakes.
  
• For older or discontinued parts, consider used/refurbished parts from reputable dismantlers — insist on a return window and clear photos of wear surfaces.
  
• Keep a small inventory of high-failure consumables (track bolts, nuts, springs, rubber pads) if you operate a fleet.
  
• When using aftermarket parts: get material spec, heat treatment, and warranty terms in writing.
  

Measurement checklist (what to measure for each part)

• Track Link / Track Shoe:
  • Link pitch (mm), pin diameter (mm), shoe width (mm), hole spacing, shoe thickness.
    
• Track Bolt / Nut:
  • Thread size (e.g., M14, 9/16"), thread pitch, bolt length, head style, required torque.
    
• Carrier / Road Roller:
  • Outer diameter, width, bore diameter, roller type (sealed bearing, bushing), mounting bracket dimensions.
    
• Sprocket:
  • Pitch, tooth count, bolt circle diameter, center bore size, tooth profile (tooth form).
    
• Idler:
  • Outer diameter, mounting face dimensions, shaft diameter, seal/grease provisions.
    
• Roller Guard / Spring:
  • Mounting hole positions, guard shape, spring length/compression rate if measurable.
    

Compatibility red flags (what to watch for)

• Matching pitch is non-negotiable — different pitch = won’t fit.
  
• Mismatched pin/bushing diameters cause premature wear.
  
• Wrong tooth profile / count on sprocket damages links.
  
• Substituting thinner/wrong-hardness shoes reduces life drastically.
  

Quality and specification considerations

• Prefer parts with documented hardness/heat-treatment or OEM material callouts for high-wear components.
  
• Sealed roller assemblies should come with bearing spec and grease protocol.
  
• For track bolts, use grade-specified fasteners and proper washers/lock devices per OEM torque chart.
  

Common solutions when OEM numbers are unavailable

• Use a combination of serial number lookup + precise measurement to identify the correct aftermarket equivalent.
  
• For discontinued sprockets or rollers, consider:
  • Matching used parts that measure correctly, or
    
  • Re-machining hubs with a new tooth ring if a local machine shop can supply certified welding/heat-treatment.
    
• Combine service manual exploded views and part illustrations to confirm mating components.
  

Inventory, spare planning & suggested minimum stock (for single machine / small fleet)

• Track bolts & nuts: at least 1 set of fasteners per track (common failure item).
  
• Track shoes: 1–2 spare pairs per machine if operating in remote or abrasive conditions.
  
• Roller/idler bearings or sealed roller assemblies: 1 spare each for top/road rollers.
  
• Sprocket: 1 spare if operating in high-hour, high-abrasion environments.
  
• Springs/guards: 1 spare set of commonly damaged guards and springs.
  

Pricing and procurement advice

• Get at least three quotes: OEM dealer, reputable aftermarket vendor, and vetted used parts supplier.
  
• Include shipping lead times and customs/import duties in total landed cost.
  
• Where cost is critical, compare life-cycle cost (lower upfront price may mean shorter life and more downtime).
  

Real-world example (short case story)

• A maintenance team needed a sprocket for a mid-size excavator but the OEM number was obsolete. They photographed the old sprocket, measured pitch and bolt circle, and sent this to two aftermarket suppliers. One supplier sent a part that fit physically but had a different tooth profile and caused accelerated link wear within weeks. The team returned it, then sourced a used OEM sprocket from a reputable dismantler that matched pitch, tooth form, and hardness. Lesson: match pitch and tooth form first; material/heat treatment second.
  

Troubleshooting common fit problems after delivery

• If the shoe fits but links bind: re-check link pitch and pin diameter; measure for worn pins/bushings.
  
• If sprocket bolts do not align: check bolt circle diameter and keying; confirm you have the correct hub version for that serial number.
  
• If roller seals fail quickly: confirm bore finish, seal seat dimensions, and grease lubrication intervals.
  

Final checklist before ordering

• Machine model and full serial number documented.
  
• Clear photographs of part and mating faces.
  
• All critical dimensions measured and recorded.
  
• OEM part number (if available) or detailed description for cross reference.
  
• Vendor confirmation (written) of compatibility and return policy.
  
• Shipping lead time and total landed cost calculated.
  

Closing notes and recommendations

• Start with the serial number and good photos — those two items solve most identification problems.
  
• When in doubt, measure twice and buy once; wrong undercarriage parts lead to rapid secondary wear.
  
• Build trusted supplier relationships (OEM and aftermarket) and keep a small strategic spares stock to reduce downtime.