How to Check the Hydraulic Lifting System on a Used HOWO Dump Truck?

A used HOWO dump truck hydraulic system should lift smoothly, hold the dump body without visible drift, and show no oil leakage around hoses, valves, PTO, pump, cylinder sleeves, or pivot hinges. Buyers should test the lifting cycle, oil condition, pressure stability, and structural support before confirming price or export shipment.

1. Start With a Full Hydraulic Walkaround

A visual walkaround helps buyers find obvious hydraulic risks before starting the engine or raising the dump body.

Check the main lift hoses, crimped fittings, hydraulic tank, pump connections, distribution valve, PTO lines, cylinder base, and rear pivot area. On a used HOWO dump truck, hoses often age faster in hot, dusty, or high-humidity working areas. Cracked rubber, exposed wire braid, wet fittings, or oil stains under the chassis are warning signs.

Small leaks should not be ignored. A light oil weep at idle can become a serious leak when the system lifts a 20 m³ tipper body or handles quarry material. If several hoses are hard, swollen, or cracked, buyers should include replacement cost in the final price discussion.

2. Check Hydraulic Oil Condition Before Testing

Hydraulic oil condition gives a quick indication of pump, valve, and cylinder health.

Open the hydraulic tank carefully and check oil color, smell, and contamination. Healthy hydraulic oil should look clean and consistent. Milky oil usually means water contamination. A burnt smell suggests overheating. Shiny metal particles on the dipstick, filter, or drain plug may indicate internal pump wear or valve scoring.

For many export buyers comparing used HOWO trucks for sale in China, oil condition is one of the simplest ways to judge whether a truck has been maintained properly. A dirty system may still lift during a short test, but it can damage seals, block valves, and reduce lifting speed after arrival.

3. Test PTO Engagement and Pump Response

The PTO should engage smoothly and transfer power to the hydraulic pump without grinding, delay, or abnormal noise.

Start the truck, keep the engine at idle, depress the clutch, and engage the PTO from the cabin control. A healthy PTO usually responds within 2–3 seconds. Listen for grinding, rattling, or high-pitched whining. These noises may point to worn PTO gears, poor transmission matching, low air pressure, or pump resistance.

Check the air line to the PTO actuator as well. If air pressure is unstable or below the normal working range, the PTO may not engage fully. In quarry or construction work, incomplete engagement can damage gear teeth and reduce hydraulic pressure during repeated lifting cycles.

4. Inspect the Telescopic Cylinder at Full Extension

The telescopic cylinder is one of the most expensive parts of a dump truck hydraulic system.

Raise the dump body on flat, solid ground and inspect each cylinder sleeve at full extension. Look for deep scratches, chrome peeling, rust pits, bending, or oil around the seals. Long vertical scoring marks are especially risky because they can tear seals during lifting and lowering.

A cylinder that looks clean but moves unevenly may still have internal seal wear. For a 6x4 or 8x4 HOWO dump truck, the cylinder must stay aligned with the subframe when the body reaches the normal tipping angle. Any side movement or twisting should be treated as a structural warning, not just a hydraulic issue.

5. Use Clear Parameters During the Lifting Test

A good inspection should record measurable results, not only visual impressions.

The following reference table can help buyers judge whether the hydraulic system is healthy enough for mining, construction, quarry, or aggregate transport.

These figures should be used as practical inspection references. Actual results may vary with body size, hydraulic brand, engine speed, oil temperature, and truck condition.

6. Run the Lifting Cycle and Watch for Shuddering

The dump body should lift smoothly without jerking, shaking, or sudden speed changes.

During the test, raise the empty body at around 1,200 RPM and observe the complete lifting cycle. If the body shudders, moves unevenly, or pauses during lifting, the system may have air in the hydraulic lines, low oil level, weak pump output, or internal valve leakage.

Do not test on soft soil or uneven ground. A tilted surface can make a good system appear unstable and can also bend the cylinder. The best test area is a flat concrete yard where the truck can be observed from the side and rear. This is also the best time to check whether the rear hinges and subframe stay aligned.

7. Perform a 10-Minute Load-Hold Safety Test

A load-hold test shows whether the control valve and cylinder seals can hold pressure after lifting.

Raise the dump body halfway, stop the engine, and leave the system in the hold position for 10 minutes. Mark the cylinder position or measure the body height. If the cylinder drops clearly during the test, internal leakage may exist inside the control valve, cylinder seals, or hydraulic circuit.

This test matters because sudden body drop creates a serious site safety risk. Buyers should never stand under a raised dump body without a mechanical safety support. If the body cannot hold position during a simple yard test, the truck should not be accepted for heavy-duty work until the fault is repaired.

8. Check Cabin Controls, Air Valves, and Limit Protection

Cabin controls must match the actual movement of the dump body accurately.

Test the lifting, holding, and lowering functions from the driver’s seat. The lever or joystick should respond clearly without excessive free play. Delayed response may come from worn linkages, leaking pneumatic lines, weak air pressure, or a sticking pilot valve.

Also check the limit valve and mechanical stop system. If the limit control is faulty, the cylinder may overextend during lifting. Overextension can damage the cylinder, subframe, or hinge structure. A proper used HOWO dump truck inspection guide should always include both hydraulic function and control safety, because the two systems work together during unloading.

9. Inspect the Subframe, Pivot Hinges, and Rear Support

A strong hydraulic system still needs a straight and stable dump body structure.

Check the subframe, rear hinge pins, lifting bracket, cylinder base, crossmembers, and welding seams. Mining and quarry trucks often carry heavy stone, wet soil, or uneven loads, which can twist the subframe or wear the rear pivot shaft. If the dump body leans to one side during lifting, inspect the structure before blaming the cylinder.

Qingdao Alston Motors checks the hydraulic lifting system, PTO response, cylinder movement, subframe condition, and tipping stability before export, helping overseas buyers confirm whether a refurbished HOWO dump truck is suitable for construction, quarry, mining, or aggregate transport.

10. Estimate Repair Cost Before Final Price Negotiation

Hydraulic inspection results should be converted into a practical repair-cost list.

For example, two new high-pressure hoses, one hydraulic oil change, and several fittings may be a manageable cost. A weak pump, scored cylinder, damaged control valve, or cracked subframe is much more serious. Buyers should record each fault with photos and videos before confirming the final price.

If the truck is being prepared for bulk vessel, Ro-Ro, or flat-rack shipment, major hydraulic repair should be completed before port delivery. Repairing a hydraulic fault after arrival may increase downtime, local labor cost, and port-side handling risk. For inspection photos, loading confirmation, and export preparation support, buyers can contact our engineering team before shipment.

Frequently Asked Questions

What hydraulic oil is commonly used for a HOWO dump truck?

L-HM46 anti-wear hydraulic oil is commonly used for standard working conditions. In very hot areas or heavy mining applications, some operators may choose a higher-viscosity hydraulic oil after confirming local climate, pump condition, and supplier recommendations.

How long should a HOWO dump body take to lift?

An empty 20 m³ dump body should usually reach its normal tipping angle in about 15–20 seconds at proper engine speed. If lifting takes more than 30 seconds, the pump, oil level, control valve, or internal leakage should be checked.

Why does the dump body shake during lifting?

Shaking or shuddering is often caused by air in the hydraulic lines, low oil level, dirty oil, worn seals, or unstable pump pressure. Buyers should repeat the test after checking oil level and bleeding the system if needed.

Is a scratched hydraulic cylinder sleeve acceptable?

Light surface marks may be manageable, but deep vertical scratches, chrome peeling, rust pits, or oil around the seals are risky. These defects can damage seals and cause pressure loss during lifting or load holding.

Can I inspect the hydraulic system without a pressure gauge?

A visual lifting test can reveal obvious problems, but a pressure gauge gives more accurate results. For serious export purchasing, buyers should combine visual checks, lifting speed, drift testing, oil inspection, and pressure measurement where possible.

Written by: Alston Motors Editorial Team
Reviewed by: Export & Technical Team
Company: Qingdao Alston Motors Co., Ltd

About Alston Motors Editorial Team:
Alston Motors Editorial Team shares practical insights on refurbished HOWO trucks, semi trailers, commercial vehicles, used cars, and export solutions for Africa and other developing markets. The content is based on the company’s experience in vehicle inspection, refurbishment, export coordination, spare parts support, and customer service for overseas buyers.