Used Haitian Mars III Hydraulic Test: What to Check at Operating Temperature
Evaluate a used Haitian Mars III under load at normal oil temperature. Learn what to record, how to compare cycles and when to ask for further diagnosis.
Ask the seller to show the exact machine running a repeatable cycle after the hydraulic oil reaches its normal operating range for the agreed test. Compare a set of cycles taken after the prescribed warm-up with a second set at stable operating temperature. Use the same mould, resin and recipe. Record the oil temperature alongside cycle times, available pressure readings and alarms so a technician can explain any change before you accept the machine.
Photo: Haitian MA 2500 III, shown as a model reference. Confirm availability and condition for the offered serial number.
Why the oil temperature belongs on the inspection report
Haitian describes the Mars III as a servo-hydraulic series and documents its servo drive and closed-loop injection design. Danfoss explains that hydraulic fluid viscosity falls as temperature rises and that the operating viscosity must suit the components. For a used press, that makes oil temperature part of the test context. Two clips taken at different temperatures or with different settings give you little basis for judging the drive.
Ask the seller for the full model and serial number, the applicable machine instructions, and records of oil, filter, pump and drive work. If a pump or drive was replaced, ask for the installed part identification and the service record. Agree with the inspector on the permitted oil temperature range and the cooling arrangement for the run. The machine and component documentation determine those limits.
Build a two-window record from one continuous run
Start both observation windows only after the operator has followed the machine's warm-up instructions. Ask for consecutive cycles rather than selected highlights. Save the recipe and write down the resin grade, mould, cooling conditions and any changes. If the operator adjusts a setting, mark it in the record and repeat the comparison under a consistent setup.
| Record | Earlier window | Stabilised window | What to resolve before accepting |
|---|---|---|---|
| Test conditions | Oil temperature and measurement point, mould and recipe revision | Same measurement point, recipe, resin and cooling setup | Explain changes in conditions before comparing the results. |
| Movement under load | Time the same clamp, injection or ejection stages that matter for the job | Repeat the same stage measurements across consecutive cycles | Ask the technician to explain any repeatable slowdown or hesitation. |
| Pressure and alarms | Record the commanded values and any actual readings available on the controller | Capture the same stages, with timestamps and alarm history | Confirm what the display measures. Have a qualified technician investigate a recurring discrepancy. |
| Oil circuit and samples | Document visible condition and identify the parts collected | Recheck for external leakage from a safe position and compare the agreed sample criteria | Record the repair, retest or remaining inspection item in writing. |
What a change during the test tells you
If a stage slows as the oil warms, record the temperature, stage and settings before proposing a repair. Fluid grade, cooling, sensor readings, valves, cylinders and the pump or drive are all candidates for a qualified diagnosis. Ask for the cause to be identified and the affected stage to be retested at the same conditions. A stable loaded run can support acceptance for the agreed trial. Remaining component life and performance with a different mould require separate evidence.
For the rest of the inspection, use the Haitian pre-purchase checklist. Where the destination plant will supply cooling water, include its available conditions in the cooling-water brief.
Common buyer questions
Can I use a seller's short video?
Use it to confirm the machine identity and visible operation. Request a longer recorded run or a witnessed inspection to assess behaviour under load at normal oil temperature.
What if my mould cannot travel to the seller?
Agree on a representative mould and load for the pre-shipment trial. List which criteria will be checked again with your actual tool at site acceptance and agree who will handle any shortfall.
Discuss a used Haitian Mars III with GEEPOW. Share the full model, serial number, target mould and any hydraulic service records you already have.