How to Source Obsolete and Discontinued Industrial Parts

Industrial machines often outlive the components inside them. A press, a CNC lathe or a packaging line can run reliably for decades, while the drive, PLC module or valve that controls it was discontinued long ago. When that part fails, maintenance teams face a hard question: where do you find something the manufacturer no longer sells? This guide walks through a structured approach that works for most obsolete components.

Why parts become obsolete

Manufacturers retire products for many reasons: a new product generation, changes in electronic components, mergers or new regulations. Most major automation suppliers publish lifecycle information, typically moving a product through phases such as active, phase-out or mature, and discontinued. During the phase-out period, the part may still be orderable for a limited time, and spare parts or repair services may continue for some years after.

The practical lesson: check lifecycle status before the part fails, because options narrow once a product is fully discontinued.

Step 1: Identify the part exactly

Most failed searches start with incomplete identification. Before contacting anyone, collect:

• The full part number, including every suffix and revision letter
• The manufacturer name, even if it is a brand that no longer exists
• The nameplate of the machine and, if available, of the component itself
• Clear photos of the part, its labels and its connections
• Where the part sits in the machine and what it does

Suffixes matter. 2 drives with the same base number can differ in voltage, firmware, communication interface or mounting. Our guide on how to read a machine nameplate explains which details to capture.

Step 2: Check the original channels first

Even when a part is listed as discontinued, the original supply chain is worth a quick check:

1. The manufacturer or its local subsidiary. They may have remaining stock, a repair service, or an official successor product with a migration guide.
2. Authorized distributors. Distributors sometimes hold stock after the manufacturer stops production.
3. The machine builder (OEM). The company that built the machine may have kept spares for its installed base or may know which substitute it now fits.

Ask specifically about a successor part. An official successor is usually the lowest risk route, although it can require changes to wiring, software or mounting.

Step 3: Search surplus and secondary markets

When official channels are exhausted, the secondary market becomes the main source. It includes:

• Surplus dealers who buy excess inventory from plants and distributors
• Stock from decommissioned machines, where parts are removed and resold
• Specialized brokers for specific families, such as legacy PLCs or servo drives
• Other plants running the same equipment, which may have spares they no longer need

Parts in this market are typically described as new (often called new surplus or new old stock), used, or refurbished. Always clarify which one you are being offered, and ask about testing and warranty. The differences are explained in more detail in OEM vs aftermarket vs remanufactured parts.

Tip: Treat any offer that looks unusually cheap for a scarce part with caution. Ask for photos of the actual unit, including labels and date codes, not stock images.

Step 4: Consider repair

For electronic and electromechanical parts, repair is often a realistic option. Specialized repair shops can service drives, power supplies, servo motors, HMIs and many circuit boards, even when new units are no longer available. Repair has limits: some components inside the unit may themselves be unobtainable, and a repaired unit is only as good as the testing behind it. Still, sending the failed part for evaluation while you search for a replacement keeps 2 options open at once.

Step 5: Look for a functional equivalent

For many mechanical and standardized parts, an exact replacement is not necessary. Bearings, seals, many pneumatic cylinders and some hydraulic components follow international standards, so equivalents from other manufacturers can fit. Cross-referencing compares dimensions, ratings and performance rather than just part numbers.

For electronic and control parts, equivalence is harder. A replacement drive or PLC may need new parameters, a different communication protocol or reprogramming. Weigh the engineering effort against the risk of staying on an unsupported part.

Step 6: Plan beyond the immediate failure

Finding 1 replacement solves today's problem, not the next failure. Once the machine is running again, consider:

• Buying a second unit as a critical spare while stock exists
• Documenting the part, its settings and any firmware version
• Starting a migration plan for the obsolete system before the secondary market dries up
• Reviewing other components on the same machine with similar lifecycle status

If the part is no longer listed by the manufacturer, a sourcing agency such as LiteHard can search distributor, surplus and stock holder networks on your behalf, so your team can focus on keeping the plant running. You can request a part with the details described above.

Avoiding common mistakes

• Searching with a partial number. You may find a part that looks right but differs in a critical detail.
• Ignoring firmware and revision. Electronic parts with the same number can behave differently.
• Skipping verification. Counterfeit and mislabeled parts exist in secondary markets.
• Waiting for the failure. Lifecycle notices usually give you time to act.

Key takeaways

• Identify the part completely, including suffixes, revision and photos, before you search.
• Check the manufacturer, distributors and the machine builder first, especially for an official successor.
• Surplus, used, refurbished and repaired parts are valid options when their condition is clearly stated and verified.
• Functional equivalents work well for standardized parts but need careful checking for electronics.
• Use each obsolete part failure as a trigger to plan spares or migration.