How do I verify if this main hydraulic pump fits my Hyundai R290NLC-7?

Our replacement pump is fully compatible with Hyundai OEM references 31N8-10050, 31N8-10010, 31N8-10060, 31N8-10080, 31N8-10051, and 31N8-10020. It houses the Kawasaki K5V140DTP tandem axial piston pump (specifically K5V140DTP1J9R-9C12-1AL) and fits all standard R290NLC-7 crawler excavators in the 29-ton class.

Does this pump assembly include regulators and pilot pump?

Yes. The pump is delivered as a complete, pre-assembled factory unit. It includes both variable displacement piston groups, the pilot gear pump, and the negative flow control (NFC) regulators pre-calibrated to factory specifications for instant plug-and-play installation.

What are the common symptoms of a failing main pump on a Hyundai R290NLC-7?

Common symptoms include sluggish boom or bucket speeds (especially when hydraulic oil heats up), engine bogging/stalling under load (failed regulators failing to destroke), straight line travel drift, and loud whining or grinding noises originating from the pump bay.

Why is flushing the system critical when replacing this pump?

If a pump suffers a mechanical failure, it releases millions of microscopic brass and steel particles into the hydraulic oil. Installing a new pump without flushing the lines, cleaning the reservoir tank, and replacing return and suction filters will carry this debris straight back into the new pump, destroying it within hours.

Hydraulic pump for Hyundai R290NLC-7

Product & Spec Guide

Hyundai R290NLC-7 hydraulic pump

OEM replacement main hydraulic pump assemblies for 29-ton crawler excavators

OEM Fit
1-Year Warranty
Europe-Wide Shipping

The Hyundai R290NLC-7 (including standard Robex 290 and R290NLC-7 series) is a highly robust 29-ton class crawler excavator designed for heavy excavation, mass earthmoving, quarrying, and demolition operations. To execute these demanding cycle times with smooth precision, the excavator relies on a dual-displacement high-pressure hydraulic circuit. The core of this power transmission system is the **main hydraulic pump assembly**, which converts the rotational torque of the Cummins diesel engine into fluid power.

Under continuous heavy load profiles, mechanical components in the rotary group will eventually wear down. Typical symptoms of main pump degradation include sluggish arm or boom speeds (particularly when the hydraulic oil gets hot and loses viscosity), engine bogging/stalling under load, straight-line travel drift, or excessive whining noises from the pump compartment. We provide **premium, OEM-quality replacement main hydraulic pumps** for the Hyundai R290NLC-7, engineered to restore factory-specification hydraulic pressure, digging speed, and overall jobsite productivity.

In need of replacement parts? View all spare parts and options for Hyundai machines →

1. OEM Compatibility & Part References

To guarantee a direct, plug-and-play fit without modifying lines, hose brackets, or control link rods, our replacement pumps are cross-referenced and fully compatible with these key OEM and manufacturer references:

31N8-10050 / 31N8-10051: Core Hyundai OEM part numbers representing the standard factory-installed main pump assembly for the Robex 290 series.
31N8-10010 / 31N8-10060 / 31N8-10080 / 31N8-10020: Validated Hyundai alternative and revised OEM numbers used across various model configurations (such as R290LC-7, R290LC-7A, R290LC-7H, and R290LC-7G).
K5V140DTP / K5V140DTP1J9R-9C12-1AL: Kawasaki high-performance swashplate-type tandem axial piston pump configured to Hyundai specifications.

If the identification nameplate on your current main pump displays any of these references, our replacement unit will fit perfectly.

2. Technical Specifications

This technical table outlines the mechanical parameters, operating pressure limits, and regulator configurations for the Hyundai R290NLC-7 main hydraulic pump:

Machine Class

29.0 – 32.0 Metric Tons (Hyundai R290NLC-7 Crawler Excavators)

Pump Configuration

Tandem axial piston double pump (two separate variable-displacement groups on a single shaft)

Displacement (cc/rev)

140 cc/rev x 2 (Kawasaki K5V140DTP)

Rated Operating Pressure

34.3 MPa (343 bar / 4,975 PSI)

Maximum Peak Pressure

37.8 MPa (378 bar / 5,480 PSI) with Power Boost engaged

Max Discharge Flow

2 x 250 L/min (2 x 66.0 gpm)

Pilot System Pump

Integrated fixed-displacement gear pilot pump (approx. 24 L/min, 3.9 – 4.9 MPa / 39 – 49 bar output)

3. Pump Assembly & Core Components

The tandem pump assembly utilizes several critical mechanical and hydraulic systems to govern oil flow and system pressure:

Tandem Piston Groups

Two inline cylinder barrels containing nine pistons each. Rotating cylinder groups draw oil from the intake port and push it into the control valve block.

Swashplate Cradle & Servo Pistons

The angle of the swashplate determines the piston stroke length. Servo pistons adjust this swashplate angle dynamically to stroke or destroke the pump based on operator demand.

NFC Regulators

Negative Flow Control (NFC) keeps the pump destroked to minimum flow when joysticks are in neutral, saving fuel. Engaging the controls drops the NFC return pressure, prompting the regulators to stroke the pump for immediate flow.

Horsepower Overrides

Mechanical torque-limiting spring packs prevent the engine from stalling. If hydraulic pressure spikes under heavy digging, these overrides destroke the swashplate automatically to protect the engine torque curve.

4. Failing Pump Diagnostics & Symptoms

Main hydraulic pumps operate under extreme pressure and thermal stress. Watch for these common indicators of pump deterioration:

Loss of Cycle Speed Under Load

Sluggish cylinder movement (especially once the hydraulic oil warms up and thins) points to internal volumetric slippage. Worn piston shoes or scratched cylinder face plates allow high-pressure oil to slip into the case drain rather than working the cylinders.

Engine Bogging or Stalling

If the engine bogs down as soon as you pull a joystick, the regulator spool valves may be stuck. They fail to destroke the swashplate when pressure spikes, overloading the engine.

Metallic Screeching or Whining

Bearing damage or cavitation (imploding air bubbles in the oil) creates a distinct, loud whining noise. Running a pump with this condition leads to catastrophic failure.

Stiff Joystick Response

If the pilot gear pump mounted on the back of the main assembly wears out, pilot circuit pressure will drop, making control joysticks heavy and sluggish.

5. Critical Hydraulic System Flushing Warning

CRITICAL REQUIREMENT: Installing a new main pump into a contaminated system will instantly void the warranty. When a main pump suffers mechanical wear or a sudden failure, it releases millions of microscopic metallic particles (brass, steel, and iron) into the hydraulic oil circuit. If these particles are not completely removed, they will enter the new pump’s tight clearances, scoring the valve plates and pistons, destroying the new unit in less than an hour.

You must thoroughly flush all lines, clean the hydraulic reservoir tank, and replace return, suction, and pilot filters before starting up the new pump.

For detailed information on pump mechanics, read about the principles of hydraulic main pumps or see our technical analysis on the function of a hydraulic main pump. When it comes to replacement, check our walk-throughs on how to change a final drive and how to repair a final drive. Make sure to get precise measurements with how to measure a final drive correctly, and prevent future failures by reading our final drive maintenance guide.

If you also operate other machines in your fleet, you may find our other machine-specific final drive optimization guides helpful: view our guides for the Hyundai R290NLC-7, the Case CX210B, the Volvo EC210B, the JCB JS200LC, the Hyundai R140LC-7, the Daewoo Solar 130LC-V, and the Hitachi ZX210LC-3 final drives, and the Kobelco SK350LC-8 main hydraulic pump, the Doosan DX255LC main hydraulic pump, the Volvo EC210C main hydraulic pump, the Case CX210 main hydraulic pump, the JCB JS160NLC main hydraulic pump, the New Holland E200SR main hydraulic pump, the Case CX330 main hydraulic pump, the Hyundai R290LC-7A main hydraulic pump, the Hyundai R140LC-7A main hydraulic pump, the Kobelco SK210LC-6 main hydraulic pump, the New Holland E215 main hydraulic pump, the Caterpillar 320D main hydraulic pump, the Hyundai R320LC-7 main hydraulic pump, the Caterpillar 312C main hydraulic pump, the Kobelco SK210LC-10 main hydraulic pump, the Volvo EC460B main hydraulic pump, the Volvo EC360B main hydraulic pump, the Volvo EC290B main hydraulic pump, the JCB JS220LC main hydraulic pump, the Kobelco SK200LC-8 main hydraulic pump, the New Holland E215B main hydraulic pump, and the Hyundai R210LC-9 main hydraulic pump.

Browse our extensive hydraulic spare parts inventory. If you need direct technical assistance or would like to request a quote, fill out our quote form below or email our team in Horsens, Denmark at info@mecatra.com.

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