The Professional Wheel Loader Manufacturer and Distributor in China

For ambient temperatures consistently above 30°C (common in African, Australian, and Middle Eastern mines), use SAE 15W-40 or SAE 20W-50 heavy-duty diesel engine oil meeting API CK-4 or CJ-4 specifications. SAE 15W-40 is the most widely recommended for mining applications. For extremely hot conditions above 40°C, SAE 20W-50 provides better high-temperature film strength. Never use single-grade oils in modern turbocharged engines — they lack the cold-start protection of multigrades. Also check that the oil meets the manufacturer’s ACEA E9 or E7 specifications. Change intervals are typically 250–500 hours in severe mining conditions, but always take oil samples at each change to monitor wear metals and extend or shorten intervals based on results.

Air trapped in hydraulic circuits causes spongy implement response and can damage pumps. To bleed properly: First, lower all attachments to the ground and shut off the engine. Loosen the hydraulic line at the highest point of the circuit (often the cylinder port or manifold) while wearing gloves and eye protection. Second, start the engine at low idle and slowly cycle the affected implement (e.g., boom up/down, arm in/out) 5–10 times while the fitting remains slightly loosened. Watch for oil and air bubbles escaping. Third, tighten the fitting while the engine is running and continue cycling the implement another 5 times. Finally, check the hydraulic tank level — bleeding removes oil, so top up to the full mark. Repeat for each circuit if you replaced multiple hoses. Always refer to your manual for specific bleed ports.

If you adjust track tension and it loosens again within a few hours, one of two problems is likely. First, the  track adjuster cylinder may have a leaking seal. This greasefilled cylinder holds tension; if the seal fails, grease escapes and tension drops. Try adding grease again — if it pushes out through the relief valve or you see grease weeping from the adjuster, rebuild or replace the cylinder. Second, the track adjuster valve (relief valve) may be stuck partially open, allowing grease to bypass. On older machines, the valve spring weakens. Also check that the grease fitting itself is not leaking. Tighten or replace it. If tension continues to drop, inspect the idler pivot and track frame — a bent frame can cause uneven tension that no amount of grease can fix.

Check suction strainer – A clogged suction screen starves the pump. Remove and clean it; if it is full of metal particles, the pump is already wearing.

Inspect the suction hose – A collapsed or kinked hose restricts flow. Replace it if soft or cracked.

Test pump pressure – With a pressure gauge at the pump outlet, run the bucket curl to relief. If pressure is below spec but pump noise is loud, the pump is worn – internal clearances have increased.

Change hydraulic oil and filter – Contaminated oil accelerates wear. If the oil is dark or smells burnt, flush the system before installing a new pump.

If you catch it early (no metal debris), you may only need a pump rebuild kit. Otherwise, plan for a pump replacement.

Check suction strainer – A clogged suction screen starves the pump. Remove and clean it; if it is full of metal particles, the pump is already wearing.

Inspect the suction hose – A collapsed or kinked hose restricts flow. Replace it if soft or cracked.

Test pump pressure – With a pressure gauge at the pump outlet, run the bucket curl to relief. If pressure is below spec but pump noise is loud, the pump is worn – internal clearances have increased.

Change hydraulic oil and filter – Contaminated oil accelerates wear. If the oil is dark or smells burnt, flush the system before installing a new pump.

If you catch it early (no metal debris), you may only need a pump rebuild kit. Otherwise, plan for a pump replacement.