A German-made reciprocating triplex plunger pump.

Spheroidal cast iron crankcase with sight glass and vented dipstick; forged, through-hardened, ground and polished crankshaft; bronze connecting rods; hardened stainless steel plunger bases; solid ceramic plungers; nitrile seals (with fabric reinforcing); stainless steel valves and cast bronze manifold.

WARNING: This product might contain a chemical known to the State of California to cause cancer, and birth defects or other reproductive harm. For more information go to

  • MP4126 Exploded View
  • MP4126 Parts List
  • MP4126 Torque Specifications
  • MP4126 Technical Drawing
  • Giant Industries Limited Warranty
  • MP4126 Installation Instructions
  • MP4126 Repair Instructions
  • Troubleshooting Guide


U.S. Metric
Flow 17.9 GPM 67.7 l/min
Maximum Discharge Pressure 1600 PSI 110 bar
Crankshaft Speed 1100 RPM
Power Consumption 20.4 hp 15.2 kW
Maximum Inlet Pressure 145 PSI 10 bar
Maximum Temperature 160 ºF 70 ºC
Plunger Diameter 1.18″ 30 mm
Stroke 1.18″ 30 mm
Crankshaft Diameter 28 mm
Crankshaft Rotation Top of Pulley Towards Manifold
Crankshaft Mounting Either Side
Inlet Ports (2) 1″ NPT
Discharge Ports (2) 3/4″ NPT
Crankcase Oil Capacity 33.8 oz. 1.0 L
Weight 66 lbs. 31 kg
Key Component Material
Manifold Aluminum Bronze
Plungers Solid Ceramic Oxide
Valves High Grade Stainless Steel
Seals Nitrile With Fabric Reinforcing
Gear End Spheroidal Cast Iron

Click the image to enlarge


RPM GPM 500 PSI 1000 PSI 1250 PSI 1600 PSI
660 10.7 3.7 7.4 9.2 11.8
715 11.65 4.0 8.0 10.0 12.85
900 14.6 5.0 10.1 12.6 16.1
1030 16.8 5.8 11.6 14.5 18.5
1100 17.9 6.2 12.3 15.4 19.8

Horsepower Requirements

The ratings shown are the power requirements for the pump. Gas engine power outputs must be approximately twice the pump power requirements shown above.

We recommend a 1.15 service factor be specified when selecting an electric motor as the power source. To compute specific pump horsepower requirements use the following formulas:
Electric HP = (GPM X PSI)/1450
Gas HP = (GPM X PSI)/1100

*Engine power varies based on horizontal or vertical orientation, as well as by makes and models from each manufacturer.


Plunger Packing Kit – Part #09042
35B 07272 V-Sleeve 3
40 07272 V-Sleeve 3
42B 07354 O-Ring, Tension Plug 3
Valve Assembly Kit – Part #09809
42B 07354 O-Ring, Tension Plug 3
44 07280 Valve Seat 6
44A 07281 O-Ring, Valve Seat 6
45 06791-0100 Valve Plate 6
46 07283 Valve Spring, Discharge 3
46A 07283 Valve Spring, Inlet 3
48A 07332 O-Ring, Tension Plug 3
53 07332 O-Ring 3

Repair Kits Available

The repair kits listed to the right are available for this pump. If you need further information about these repair kits, or have questions about other specific parts for your pump, please contact you local Giant distributor or contact Giant customer service.

Service & Repair

Giant provides service on each pump and accessory that we sell. Many basic repair procedures are covered in the Giant repair manual. For all other questions on service or repair needs please contact your local Giant distributor.