2026-10-15

Buying a Used Milk Separator: What to Inspect Before You Pay

A second-hand separator can be a sensible purchase, but the machine you inspect is rarely the machine described in the advert. This guide sets out an inspection sequence you can follow on site, and the questions that should be answered in writing before money changes hands.

The goal is not to judge the machine from photographs, but to build a record of its actual condition, its missing parts, and what it will cost to put it into service.

Scope of this guide: this covers a second-hand machine inspected before you pay, where documents may be missing and consumable parts still have to be checked for availability. For a new machine arriving from your supplier, use the receiving inspection checklist instead. For matching one replacement part to a machine you already own, use the parts inquiry checklist.

1. Start with the machine history

Ask the seller for the information that connects the machine to a real record:

  • The model marking on the machine and the year it was put into service.
  • Which documentation still exists: operating manual, order or purchase record, and any inspection or material documents.
  • What has been repaired or replaced, and when.
  • Whether the machine was used daily, seasonally, or stored unused — and how it was stored.
  • Why it is being sold.

A machine with a documented service history is easier to assess than one sold without any record. If the seller cannot say which model it is, treat the model name as unknown until it is confirmed.

2. Inspect the bowl assembly carefully

The bowl is usually the most expensive part of the machine, so it deserves the most attention. Clean the assembly enough to see the surfaces, then check:

  • All discs are present, and they match the assembly rather than being a mixed set.
  • Discs are not bent, chipped, or heavily scored, and the disc holes or passages are clear.
  • The bowl body and cover show no cracks, deep dents, or heavy pitting.
  • Spacers, centre nuts, and any locking components are present and undamaged.
  • The bowl spins freely by hand and does not bind, scrape, or rock on its seat.

Ask whether the bowl has ever been dropped, machined, or repaired, and whether any non-original part has been fitted. A bowl with missing or mixed components can be a problem long before it becomes a visible one.

3. Check the drive and electrical parts

For a powered machine, inspect the parts that decide whether it will run smoothly and safely:

  • Read the motor and electrical markings, and write them down.
  • Check the power cable, plug, switch, and any controller housing for cracks, burning smell, or exposed conductors.
  • Turn the motor or drive by hand where it is accessible and feel for roughness or end float.
  • Look at the drive coupling, shaft, bearings, and mounting points for damage or missing fasteners.
  • Check the base and feet: a base that is cracked, bent, or missing damping parts will not hold the machine steady.

Do not connect a machine to power if the cable, plug, switch, or housing is damaged. Have the electrical parts inspected before running it.

4. Examine the milk-contact parts

List every component that touches milk and inspect each one: receiver, float chamber and float, bowl and discs, gaskets and seals, and outlet spouts.

  • Gaskets and seals that are hardened, flattened, cracked, or cut will need replacing.
  • Internal surfaces should be free of heavy scale, residue, and rust staining.
  • Outlets and connections should be complete, with no missing spouts, caps, or fittings.
  • Everything that touches milk should be cleanable and free of repairs that would trap residue.

Photograph the inside of the receiver and the bowl assembly, because these areas are difficult to judge from the outside.

5. Confirm spare-part availability before paying

A used machine is only worth its price if the consumable parts can still be replaced. Before agreeing a price:

  • Identify the parts that wear in normal service: seals and gaskets, discs or the disc stack, brushes or bearings where applicable, and any plastic or rubber components.
  • Ask whether those parts are still available for this exact model, and how they are ordered.
  • Compare the parts list against the replacement parts catalog to see which items will need to be sourced, and confirm compatibility against your machine record rather than the catalog name alone.
  • If a critical part is unavailable or unmatchable, treat that as a reason to renegotiate the price or walk away.

6. Run the machine if it is safe to do so

Where the machine can be run safely and the seller agrees, watch it through a short cycle rather than only switching it on:

  • Listen at startup and during steady running for unusual noise, scraping, or rattling.
  • Watch for vibration, walking across the surface, or movement of the base.
  • Check for leaks at joints, seals, and outlets.
  • Observe whether the outlets flow steadily or surge.
  • Stop the machine immediately if you hear scraping, feel heavy vibration, or see a leak at the bowl area.

Note that a short test run does not prove the machine is in good condition, and a machine that cannot be tested should be priced accordingly.

7. Record everything before you pay

Write down what you found, and keep it with the machine:

  • Model marking and electrical details as actually observed.
  • Serial or identification marking, if present.
  • Photographs of the complete machine, the bowl assembly, the milk-contact parts, and any damage.
  • Which parts are missing, worn, or unverified.
  • Which documents the seller is providing.
  • The price agreed, and what it includes.

Inspection checklist

  • Machine history and available documents requested.
  • Model marking and electrical details recorded from the machine itself.
  • Bowl assembly complete, with discs and spacers accounted for.
  • Bowl clean of cracks, deep dents, and heavy pitting; spins freely by hand.
  • Cable, plug, switch, controller, and housing inspected for damage.
  • Drive coupling, shaft, bearings, base, and feet checked.
  • Milk-contact parts and seals inspected and photographed.
  • Spare-part availability confirmed for the consumable items.
  • Short run observed for noise, vibration, leaks, and flow behaviour where safe.
  • Inspection record written and photographs stored with the machine.

Before you commit

Compare the inspection record with the seller's description, and price the machine with the cost of the parts you already know it needs. If the seller cannot confirm the model or the availability of consumable parts, treat those as open risks rather than assumptions.

For a used machine you plan to operate, the replacement-part record checklist shows how to keep the service record, and the cleaning and reassembly checklist covers the routine after the first inspection. Send the inspection record and photographs to the ANDUUK contact page if you want the parts position reviewed before you buy.

Related maintenance resources

Use the ANDUUK replacement parts catalog to match seals, discs, outlets, motor components and cleaning tools to the correct machine assembly.

Browse replacement parts · Read the cleaning and reassembly checklist · Read separator FAQs