Cat Pump HS56 / 668BGG1

Cat Pump 668BGG1 / HS56 Replacement Pump – 8 GPM @ 3500 PSI

Having trouble finding replacement parts or a full replacement for your Cat Pump HS56 or Cat Pump 668BGG1? This 8 GPM, 3500 PSI pressure washer pump is the direct solution, built with the same proven quality and parts availability you expect from Cat Pumps.

Repair Kits

  • 33820 – Requires two kits

  • 30799 – Requires one kit

Compatible Models

  • Cat Pump HS56

  • Cat Pump 668BGG1

(Direct replacement – no modifications required.)

Key Features

  • Triplex plunger design – 3 plunger rods for maximum durability and smooth operation

  • Forged brass manifold for strength and corrosion resistance

  • 304 stainless steel valve assemblies

  • Solid ceramic plungers for long service life

  • NBR (Buna-N) seals and O-rings as standard

  • 304 stainless steel and bronze plunger rods for higher operating pressures

Drive Options

Operates at 1760 RPM, allowing multiple drive setups:

  • Direct drive with bell housing & flexible coupling

  • Clutch drive

  • Belt drive

Technical Specifications

  • Max Flow: 8 GPM / 30.3 LPM

  • Max Pressure: 3000 PSI

  • Inlet Port Size: 1/2" NPT(F)

  • Discharge Port Size: 3/8" NPT(F)

  • RPM: 1760

  • Drive Types: Belt, Clutch, Flexible Coupling, Bellhousing

  • Material: Brass manifold with stainless steel internals

Resources

 

Cat Pump 668BGG1 / HS56 Replacement Pump – FAQ

Is the Cat Pump 668BGG1 discontinued?

Yes, the Cat Pump 668BGG1 is no longer in production. However, this HS56 series replacement pump is a direct match with the same performance and specifications, ensuring you can continue to run your system without modifications.

What pump replaces the Cat Pump 668BGG1?

The Cat Pump HS56 is the direct replacement. Both models share the same design, flow rate (8 GPM), and pressure rating (up to 3500 PSI).

Can I still buy parts for the Cat Pump 668BGG1?

Yes. While the pump itself has been replaced by the HS56, repair kits and individual parts (like seal kits and valve kits) are still available. For a standard rebuild you’ll need:

  • 33820 Seal Kit – two kits required

  • 30799 Valve Kit – one kit required

What’s the difference between the Cat Pump HS56 and Cat Pump 668BGG1?

The pumps are essentially the same. The 668BGG1 was a private-labeled version of the HS56. Both share the same specifications and internal components, making them interchangeable for service and replacement.

Can I swap a Cat Pump 668BGG1 with an HS56 without changes?

Yes. The pumps are direct bolt-in replacements with identical mounting dimensions, drive options, and performance. No modifications are needed.

What drive options are available for this pump?

The HS56/668BGG1 pump runs at 1760 RPM and can be driven by:

  • Direct drive with bell housing and flexible coupling

  • Clutch drive

  • Belt drive

What are the technical specifications of the Cat Pump HS56 / 668BGG1?

  • Flow: 8 GPM / 30.3 LPM

  • Pressure: Up to 3000 PSI

  • Inlet Port: 1/2" NPT(F)

  • Discharge Port: 3/8" NPT(F)

  • Material: Brass manifold, stainless internals, ceramic plungers

  • RPM: 1760

Where can I find the service manual or data sheet?

We provide direct access to the service manual, data sheet, and the official Cat Pumps sell sheet on this page for your convenience.