Hydraulic Pump Assembly 374 2025 3742025 PVC90 Fits for Caterpillar E303.5E 303.5E 49c2d009 c5b2 4f63 b3f4 aea295524eed.jpg

374-2025 3742025 Hydraulic Pump Assembly PVC90 for Caterpillar E303.5E 303.5E

461-0539 is an aftermarket new hydraulic pump assembly for Caterpillar E303.5E2 and 303.5E2. It supplies the oil flow and pressure the machine hydraulics work with.

Category: Hydraulic Pump Assembly

Description
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461-0539 Hydraulic Pump Assembly is an aftermarket replacement hydraulic pump assembly for Caterpillar, including E303.5E2, 303.5E2. The main hydraulic pump converts engine power into pressurized oil flow. Supplied by LIONKITS as new, aftermarket.

461-0539 Hydraulic Pump Assembly Specifications

Product Type: Hydraulic Pump Assembly
Part Number: 461-0539, 4610539
Compatible Brand: Caterpillar
Condition: new, aftermarket
Country of Origin: China

Caterpillar Models Compatible with the 461-0539 Hydraulic Pump Assembly

Fitments: 303.5E2CR Mini Hydraulic Excavator CR600001-UP (MACHINE) POWERED BY C1.7 Engine
303.5E2 CR Mini Hydraulic Excavator AC500001-UP (MACHINE) POWERED BY C1.7 Engine
303.5E2 CR Mini Hydraulic Excavator CR900001-UP (MACHINE) POWERED BY C1.7 Engine

Your model is not listed? Contact LIONKITS via live chat or email with your machine model and nameplate photo, and we will confirm compatibility.

What Does a Hydraulic Pump Do?

The main hydraulic pump converts engine power into pressurized oil flow. That oil moves the boom, arm, bucket, swing and travel functions, so every machine movement depends on it. Because it takes the most punishment, it is usually the first major hydraulic component to wear out.

Signs the Part Needs Replacing

Slow or weak movement on all functions: when everything is slow at once, not just one circuit, the pump is the most likely source.
Whining, knocking or grinding noise: internal wear or cavitation, especially on start-up or when the oil is cold.
Hydraulic oil running hot: internal bypass leakage turns pressure into heat.
Metal particles in the filter or case drain: a failing pump sheds metal and pushes out more case drain flow.
Erratic or spongy movement, foamy oil: air entering the suction line, or aeration, upsets pump flow.

These symptoms overlap with clogged filters, low oil, air in the suction line and worn valves, so check the filters and oil level before replacing the part.

How to Order and Install the 461-0539 Hydraulic Pump Assembly

Confirm your machine model, the part number and the pump model on your existing pump before ordering.
Send a photo of the old pump or the nameplate if you are not sure; LIONKITS will confirm fitment for you.
Change the hydraulic oil and the return filters before fitting the new pump; a new pump installed in contaminated oil will fail early.
If the old pump failed internally and shed metal, flush the tank, hoses and oil cooler and inspect the control valve and motors for contamination.
Fill the pump case with clean hydraulic oil and prime the pump as the service manual specifies before the first start.
Check the suction line, strainer and fittings for air leaks, and tighten bolts to the specified torque.
Run the machine at low speed first, then check pressure, noise and leaks.

Frequently Asked Questions

What is the 461-0539 Hydraulic Pump Assembly?

The 461-0539 Hydraulic Pump Assembly is an aftermarket replacement hydraulic pump assembly for Caterpillar , supplied as new, aftermarket under part numbers 461-0539, 4610539.

Which Caterpillar models does the 461-0539 Hydraulic Pump Assembly fit?

It is listed for E303.5E2, 303.5E2 and other models in the compatibility list above. If you are unsure, send your machine nameplate to LIONKITS for confirmation.

How do I know my hydraulic pump is failing?

Typical signs are slow or weak movement on all functions, whining or knocking noise, hot hydraulic oil, metal particles in the filter or case drain and erratic or spongy movement.