Maintaining the hydraulic system of small four-wheel tractors focuses on "regular oil management, component inspection, and pollution prevention" to ensure stable operation and extend service life.
Below is a practical, step-by-step maintenance guide:
1. Daily Routine Maintenance (Before/After Operation)
1.1 Pre-Operation Checks (5-Minute Quick Inspection)
Oil Level & Quality: Park the tractor on flat ground, shut down the engine, and check the hydraulic oil level (must be between MAX and MIN scales). Visually inspect oil clarity-no turbidity, foam, or impurities allowed.
Leakage Inspection: Quickly check pipe joints, cylinder ends, and the pump/valve body for oil stains or seepage; tighten loose joints immediately.
Component Appearance: Ensure the radiator is free of dust/straw clogging, and the control valve lever moves flexibly.
1.2 Post-Operation Maintenance (After Shutdown)
Cleaning: Wipe the oil tank cap, radiator surface, and hydraulic components with a clean rag to prevent dust accumulation.
Pressure Relief & Reset: Return the hydraulic control valve to the neutral position to release residual system pressure.
Drainage: Every 50 working hours, open the oil tank bottom drain valve to discharge condensed water and sediment (especially in humid environments).
2. Regular Periodic Maintenance (By Working Hours)
2.1 Every 100 Working Hours
Lubricate the hydraulic cylinder piston rod with lithium-based grease to prevent rust and reduce friction.
Clean the air filter on the oil tank cap (avoid dust entering the tank).
Inspect rubber oil hoses for cracks/aging; replace if damaged.
2.2 Every 200 Working Hours
Clean the hydraulic oil suction filter (detachable type) to avoid clogging and insufficient oil intake.
Check the cooling fan (electric/belt-driven) for normal operation; tighten loose belts or repair faulty motors.
2.3 Every 500–800 Working Hours (Core Maintenance)
Full Oil Change: Drain old hydraulic oil completely, clean the oil tank interior with diesel oil, and refill with specified oil (e.g., 46# anti-wear hydraulic oil).
Filter Replacement: Replace the oil filter element synchronously with oil changes; ensure the new filter gasket is coated with oil for sealing.
Seal Inspection: Check pump shaft seals, valve core seals, and cylinder piston seals for wear/leakage; replace aging parts with original components.
2.4 Every 1 Year (Annual Overhaul)
Calibrate the hydraulic pump output pressure and relief valve setting pressure with a pressure gauge (align with the manufacturer's rated value).
Disassemble and clean the control valve and one-way valve; remove impurities and apply lubricant to ensure flexible valve core movement.
Replace rubber oil hoses (even if no obvious damage) to avoid sudden bursts due to aging.
3. Key Maintenance Taboos & Precautions
Oil Management: Do not mix different types/grades of hydraulic oil; use only manufacturer-specified oil (comply with GB/T 11118.1 for anti-wear oil).
Pollution Prevention: Always clean the oil tank cap and component surfaces before disassembling to avoid dust/impurities entering the system.
Temperature Control: Stop operation immediately if oil temperature exceeds 85°C; clean the radiator or reduce load to cool down (overheating accelerates oil oxidation and seal aging).
Load Avoidance: Never exceed the rated lifting load; avoid sudden starts/stops of the hydraulic system to reduce pressure impacts on components.
4. Special Scenario Maintenance
Cold Regions: Use 32# anti-wear hydraulic oil in winter; preheat the system at idle for 5–10 minutes before operation to ensure oil fluidity.
High-Temperature/Heavy-Load: Shorten oil change cycles to 300–500 working hours; clean the radiator every 150 working hours to enhance heat dissipation.
Dusty Environments: Replace the air filter every 3 months; add a pre-filter to the oil intake to reduce dust contamination.
