6 GPM at 3,600 RPM • Automatic High/Low Operation • 1/2" Keyed Shaft • Minimum 8 HP Engine

Upgrade or replace the hydraulic pump on a compatible log splitter with the WSD31-253 Two-Stage Hydraulic Pump. The pump delivers a nominal 16 GPM at 3,600 RPM, providing rapid cylinder movement under low resistance before automatically shifting to lower-flow, high-pressure operation when the wedge encounters a difficult log.

This high/low design allows a compatible log splitter to achieve faster cycle times and strong splitting performance without requiring the substantially larger engine associated with a comparable single-stage pump. It is designed for direct-drive use with a horizontal-shaft gasoline engine rated at 8 HP or greater.

Key Features & Benefits

• 16 GPM Nominal Flow
  Provides high-volume hydraulic flow at 3,600 RPM for fast cylinder travel during the low-pressure portion of the splitting cycle.
• Automatic Two-Stage Operation
  The pump automatically unloads the high-volume stage when system pressure rises, allowing the smaller stage to produce the pressure needed to split difficult wood.
• Faster Log Splitter Cycle Times
  Rapid low-pressure cylinder movement reduces waiting time between splitting strokes.
• Works with Smaller Gas Engines
  Requires a minimum 8 HP gasoline engine, allowing strong hydraulic performance without an oversized power source.
• 1/2" Keyed Drive Shaft
  Accepts compatible pump couplers designed for a 1/2-inch shaft and 1/8-inch Woodruff key.
• Clockwise Rotation
  Designed for clockwise operation when viewed from the drive-shaft end.
• Standard Four-Bolt Mounting Pattern
  Uses four mounting holes spaced 2 inches on center with a 2.83-inch bolt circle.
• Open-Center Hydraulic Systems Only
  Intended for compatible log splitters and other equipment using an open-center control valve.
• Direct-Drive Configuration
  Designed to connect directly to a compatible engine through a properly aligned flexible coupling.
• Versatile Hydraulic Applications
  Suitable for compatible log splitters, hydraulic presses, clamping units, and compactors.

How the Two-Stage Pump Works

During normal cylinder travel, both pump sections work together to provide approximately 16 GPM, moving the log splitter wedge quickly toward or away from the wood.

When the wedge encounters resistance and hydraulic pressure rises, the pump automatically unloads the larger high-flow section. The smaller section continues supplying lower flow at higher pressure, allowing the splitter to develop its maximum force without stalling the engine.

Once resistance decreases, the pump automatically returns to high-flow operation.

Ideal Applications

This 16 GPM pump is suitable for compatible:

• Gas-powered hydraulic log splitters
• Hydraulic shop presses
• Clamping equipment
• Compactors
• Custom open-center hydraulic systems
• Replacement and equipment-building projects

Proper compatibility depends on engine horsepower, shaft rotation, mounting pattern, coupler dimensions, port configuration, pressure requirements, and hydraulic-system design.

Quick Specifications

The GP-CBN manufacturer documentation identifies the pump as a 16 GPM model rated for 3,600 RPM with a 400–900 PSI unloading range and 3,000 PSI high-pressure maximum. 

Package Contents

• One 16 GPM two-stage hydraulic pump

The product page does not list a pump mount, flexible coupling, hydraulic hoses, fittings, control valve, mounting hardware, reservoir, or hydraulic fluid as included.

Important Compatibility Information

This pump is not universal. Before ordering, verify:

• Engine produces at least 8 HP
• Engine operates near 3,600 RPM
• Engine has a horizontal output shaft
• Pump requires clockwise rotation
• Coupling accepts a 1/2-inch keyed pump shaft
• Mounting bracket matches the four-bolt pattern
• Inlet and outlet sizes match the hydraulic system
• Control valve is designed for an open-center system
• Reservoir and suction hose can supply the required flow
• All hydraulic components meet the system’s pressure requirements

The engine and pump shafts must be accurately aligned. Improper alignment can damage the flexible coupling, pump shaft, engine bearings, or mounting bracket.