The hydraulic oil filter of small four-wheel tractors should be replaced synchronously with hydraulic oil changes (every 500–800 working hours or 1 year, whichever comes first); additionally, the suction filter (if detachable) needs regular cleaning.
1. Standard Replacement Cycle (Core Requirement)
| Filter Type | Replacement/Cleaning Cycle | Key Basis |
|---|---|---|
| Oil Filter Element (Pressure Filter) | Replace every 500–800 working hours / 1 year (synchronous with hydraulic oil change) | The filter element traps impurities generated during oil use; replacing it with new oil avoids residual impurities contaminating the new oil, ensuring system cleanliness. |
| Suction Filter (Inlet Filter) | Clean every 200 working hours; replace every 1–2 years (or when clogged/damaged) |
Installed at the oil tank inlet, it is prone to blockage by sediment; regular cleaning ensures sufficient oil intake for the hydraulic pump. |
2. Early Replacement Triggers (Even Within Cycle)
Replace the oil filter element immediately if any of the following occurs:
Hydraulic oil deteriorates early (turbid, with metal particles or sediment), indicating severe system contamination.
The hydraulic system has faults such as insufficient pressure or slow operation, which are caused by filter clogging (confirmed by inspection).
The filter housing is damaged, leaking oil, or the seal gasket is aging (affecting filtering effect and system tightness).
After repairing major hydraulic components (e.g., pump, cylinder replacement), new impurities may enter the system, requiring filter replacement together with oil change.
3. Key Replacement Notes
Use original or model-matching filters to ensure filtering precision and compatibility with the hydraulic system (inferior filters may have poor filtering effect or cause oil flow resistance).
When installing a new oil filter element, apply a thin layer of hydraulic oil to the rubber gasket first-this enhances sealing and avoids gasket damage during tightening.
Tighten the filter element properly: Screw it by hand until the gasket fits the mounting base, then use a wrench to tighten 1/2–3/4 of a turn (over-tightening will damage the gasket, leading to oil leakage).
After replacement, run the hydraulic system at idle speed for 5–10 minutes, then check for oil leakage at the filter connection-tighten immediately if leakage is found.
