Excavator Pump

First, Types of Excavator Hydraulic Pumps

Excavators primarily use hydraulic piston pumps(variable displacement) for efficiency and power. Some older/smaller models may use gear pumps.  

1. Axial Piston Pumps (Most Common in Excavators)

How it Works: Pistons move in a circular motion inside a cylinder block, controlled by a swashplate.  

Variable Displacement: Adjusts oil flow based on demand (saves energy).  

Brands:  

Kawasaki (K3V, K5V) – Used in many JCB, Hitachi, and Kobelco excavators.  

Rexroth (A10VO, A11VO) – Common in Caterpillar, Volvo.  

Linde / Danfoss – Used in some modern JCB and Liebherr machines.  

2. Gear Pumps (Less Common, Mostly in Older/Small Machines)  

Fixed Displacement: Simpler but less efficient.  

Example: Used in some compact/mini excavators.  

Second, Symptoms of a Failing Excavator Hydraulic Pump 

1.Slow or Weak Movements (Boom, Arm, Swing, Travel).  

2.Hydraulic System Overheating.  

3.Unusual Noises (Whining, grinding, knocking).  

4.Oil Leaks (Around pump seals or shaft).  

5.Jerky or Erratic Operation.  

Third, Common Causes of Pump Failure  

1.Contaminated Oil (Dirt, metal particles damage pump internals).  

2.Worn Pistons/Shoes (Due to age or poor maintenance).  

3.Swashplate Damage (Causes loss of pressure control).  

4.Bearing Failure (Leads to shaft play and leaks).  

5.Overpressurization (From faulty relief valves).  

Fourth, How to Identify the Correct Replacement Pump?  

1. Check Machine Model & Serial Number (e.g., JCB JS220, Cat 320D).  

2. Find Pump Model/Part No. (Stamped on the pump body or in the service manual).  

3. Match Specifications:

Displacement (cc/rev – e.g., 45cc, 63cc).  

Max Pressure (Bar/PSI – e.g., 350 bar, 5000 PSI).  

Shaft Type (Spline, keyway, or flange-mounted).

Fifth, Repair vs. Replace?

1.Repair (Seal/Bearing Kit): Cheaper if only minor wear.  

2.Replace Entire Pump: Needed for major damage (scored pistons, swashplate wear).  

3.Remanufactured Pump: Cost-effective middle option.  

Sixth, Preventive Maintenance Tips  

1.Change Hydraulic Oil & Filters Regularly.  

2.Monitor Oil Contamination (Use particle counters).  

3.Check for Leaks & Unusual Noises Early.  

4.Avoid Overloading the Hydraulic System.  

Best hydraulic pump for excavators

Excavator hydraulic pump types

Excavator hydraulic pumps