The hydraulic pump is part of the excavator’s hydraulic system. When the hydraulic pump fails, the excavator will not operate normally. What are the most common faults with an excavator hydraulic pump? Your excavator service technician will show you.
Most gear pump faults are caused by wear of the internal friction pair. Its normal wear increases radial and axial clearance (sectional clearance) and the phenomenon of leakage in the gear pump is exacerbated. In serious cases, the holes or plates on both sides of the pump casing cannot be repaired. In addition, the shaft seal is often damaged.
Low Hydraulic Pressure
One of the most common faults in an excavator’s hydraulic pump is low hydraulic pressure. When the pump fails to generate enough pressure, the machine may become sluggish or unable to lift heavy loads.
Causes:
- Worn-out pump components (such as pistons or vanes);
- Hydraulic fluid leaks in hoses or seals;
- Blocked or clogged filters restricting oil flow;
- Air in the hydraulic system, leading to pressure loss.
Fixes:
- Inspect and replace worn-out pump parts if they show signs of damage;
- Check for leaks in the hydraulic hoses, seals, and connections, and repair them immediately;
- Replace clogged hydraulic filters and ensure the oil is clean;
- Bleed the system to remove trapped air that might be causing pressure issues.
Overheating Hydraulic Pump
Hydraulic pumps can overheat if they are overworked or not properly maintained. Overheating leads to loss of efficiency, oil breakdown, and potential damage to internal components.
Causes:
- Low hydraulic oil levels causing increased friction;
- Dirty or contaminated hydraulic fluid, reducing cooling efficiency;
- Blocked cooling systems or radiator issues;
- Excessive load on the pump, making it work harder than necessary.
Fixes:
- Ensure the hydraulic oil is at the correct level and top it up if needed;
- Regularly flush and replace hydraulic oil to maintain proper lubrication and cooling;
- Clean or repair cooling components (radiators, oil coolers, and fans) if they are clogged;
- Avoid overloading the excavator beyond its capacity, as this stresses the pump.
Noisy Hydraulic Pump (Cavitation)
If your excavator’s hydraulic pump is making loud whining, knocking, or screeching noises, it could be suffering from cavitation. This happens when air bubbles form in the hydraulic fluid, causing shock waves that damage internal components.
Causes:
- Low hydraulic oil levels, allowing air into the system;
- Clogged suction filters, restricting oil flow;
- Leaky suction hoses, letting air enter the pump;
- Wrong hydraulic oil viscosity, leading to poor lubrication.
Fixes:
- Refill hydraulic oil to the recommended level to prevent air intake;
- Replace clogged suction filters to ensure smooth oil flow;
- Inspect and tighten or replace suction hoses to stop air leaks;
- Use the manufacturer-recommended hydraulic oil to maintain proper lubrication.
The Vane Pump and The Radial Piston Pump
The vane pump differs from the gear pump in that the normal wear is very low and the service life of the components is long. The main cause of vane pump failure is oil contamination because the moving vane pump pair is closely matched and when contaminants enter the friction pair it is easy to cause abnormal stagnation or wear. In addition, the self-priming performance of a vane pump is not as good as that of a gear pump, especially for a vane pump with a small displacement. Therefore, whether the oil is clean and whether the oil suction is smooth are two issues that need special attention in vane pump operation.
The weakness of the radial piston pump in design and motion performance is that the radial force is large, the self-priming ability is poor, and the precision of the alignment between the piston and the piston bore is high; the machining precision of the axial piston pump parts should be high. Therefore, the piston pump requires high oil cleanliness, i.e. the piston pump requires higher oil filtration accuracy than the gear pump.
Analysis The Causes
A failing hydraulic pump can seriously affect an excavator’s performance, leading to low power, overheating, and noisy operation. Regular maintenance, using clean hydraulic oil, checking for leaks, and replacing worn-out parts, can prevent most of these issues.
Correct analysis of the causes of excavator defects and their timely elimination, as well as reinforcement of excavator maintenance, are prerequisites for the efficient and safe operation of excavators, to which all attention must be paid in practical work.