Hydraulic pressure is the key factor that allows excavators to perform heavy tasks such as digging, lifting, swinging, and traveling. When hydraulic pressure drops below the normal operating range, the entire machine performance decreases.
Low hydraulic pressure is a common issue in construction and mining operations. If not diagnosed and repaired promptly, it may lead to hydraulic pump damage, system inefficiency, and costly downtime.
Understanding the possible causes and solutions can help equipment operators and maintenance technicians restore proper machine performance quickly.
Before identifying the cause, it is important to recognize the typical symptoms of low hydraulic pressure.
Operators may notice the following problems:
- Weak digging force
- Slow boom, arm, or bucket movement
- Delayed hydraulic response
- Excavator unable to lift heavy loads
- Reduced swing speed
- Machine movement becomes unstable
These symptoms usually indicate that the hydraulic system cannot maintain sufficient pressure.
The hydraulic pump is responsible for generating system pressure. Over time, internal components such as pistons, gears, or bearings may wear out.
When this happens, internal leakage increases and the pump can no longer maintain proper pressure levels.
Common signs of pump wear include:
- abnormal noise
- overheating
- reduced hydraulic performance
External or internal oil leakage can reduce the overall pressure of the hydraulic system.
Possible leakage sources include:
- damaged hydraulic hoses
- worn seals
- cracked hydraulic fittings
- leaking cylinders
Even small leaks can significantly affect system pressure.
Control valves regulate the flow and pressure of hydraulic oil. If a valve becomes stuck, worn, or contaminated with debris, it may restrict oil flow or allow pressure loss.
This can cause uneven or slow movement of the excavator.
Hydraulic oil plays an essential role in transferring pressure within the system.
If the oil level is too low or the oil becomes contaminated with dirt or metal particles, the hydraulic pump cannot operate efficiently.
Contaminated oil can also damage internal hydraulic components.
The relief valve protects the hydraulic system from excessive pressure. However, if the relief valve is incorrectly adjusted or damaged, it may open prematurely.
This causes hydraulic oil to bypass the system, leading to pressure loss.
When troubleshooting low hydraulic pressure, technicians usually follow these inspection steps:
- Check Hydraulic Oil Level. Ensure the hydraulic oil tank contains sufficient oil and that the oil quality meets specifications.
- Inspect for Oil Leaks. Check hydraulic hoses, connectors, cylinders, and valves for visible oil leakage.
- Test Hydraulic Pump Pressure. Using a pressure gauge, technicians can measure the output pressure of the hydraulic pump. Low pump pressure may indicate internal wear.
- Inspect Control Valves. Control valves should be inspected for contamination, blockage, or internal damage.
- Check the Relief Valve. Verify whether the relief valve pressure setting meets manufacturer specifications.
Proper maintenance is essential for preventing hydraulic pressure problems.
Recommended practices include:
- regularly replacing hydraulic oil and filters
- inspecting hydraulic hoses and seals
- maintaining clean hydraulic oil
- monitoring hydraulic system pressure and temperature
- avoiding continuous heavy-load operation
Routine maintenance significantly reduces the risk of hydraulic system failure.
Low hydraulic pressure can seriously affect excavator performance and productivity. The problem is often caused by hydraulic pump wear, oil leakage, contaminated hydraulic oil, or faulty control valves.
By performing systematic inspections and regular maintenance, operators can identify problems early and maintain stable hydraulic performance.
Proper hydraulic system care not only improves machine efficiency but also extends the lifespan of key excavator components.
Guangzhou Tieqi Construction Machinery Co., Ltd. specializes in supplying high-quality spare parts for construction and mining equipment.
Our main products include:
- Excavator hydraulic pumps
- Hydraulic control valves
- Swing motors
- Final drives
- Diesel engines
- Electrical components
With extensive experience in the global construction machinery industry, we provide reliable aftermarket solutions for customers worldwide.