Views: 0 Author: Site Editor Publish Time: 2026-11-07 Origin: Site
The Parker P31 and P51 series are heavy-duty external gear pumps designed specifically for mobile hydraulic systems and commercial vehicle applications. Manufactured by Cissoko Hydraulic, these pumps feature cast-iron housings, roller-bearing support, and pressure-balanced thrust plates, ensuring reliable hydraulic power even under demanding operating conditions.
The P31 and P51 series are widely used in applications such as dump trucks, refuse trucks, hook-lift trucks, moving-floor trailers, wreckers, and various other types of mobile hydraulic equipment. Available in a range of displacements, shaft configurations, and mounting styles, these pumps offer flexible solutions for hydraulic systems driven by power take-off (PTO) units.
The P31 and P51 series feature a three-piece cast iron construction with heavy-duty roller bearings and balanced thrust plates. The robust housing provides mechanical strength, while the balanced thrust plate design helps maintain internal sealing and reduce friction during operation.
An important structural difference between these pumps and their P30/P50 counterparts is the use of steel alignment dowel pins in the P31 and P51 designs. This construction allows the P31 and P51 to operate at higher pressure ratings in corresponding gear-width configurations.
Both series are available in single-section and multiple-section configurations, with different shaft types, mounting flanges, and port arrangements. This flexibility makes them suitable for applications requiring different flow rates and hydraulic circuit combinations.
| Parameter | P31 Series | P51 Series |
|---|---|---|
| Pump type | External gear pump | External gear pump |
| Construction | Cast iron | Cast iron |
| Bearing type | Roller bearing with dowel pins | Roller bearing with dowel pins |
| Displacement range | 16.1–64.6 cc/rev | 20.9–104.5 cc/rev |
| Maximum continuous pressure | Up to 207 bar | Up to 207 bar |
| Maximum speed | 2,400 rpm | 2,400 rpm |
| Configuration | Single / Multiple sections | Single / Multiple sections |
| Mounting | SAE configurations | SAE configurations |
| Frame Size | Gear Width | Displacement | Maximum Continuous Pressure |
|---|---|---|---|
| 05 | 1/2 in | 16.1 cc/rev | 207 bar |
| 07 | 3/4 in | 24.2 cc/rev | 207 bar |
| 10 | 1 in | 32.3 cc/rev | 207 bar |
| 12 | 1-1/4 in | 40.4 cc/rev | 207 bar |
| 15 | 1-1/2 in | 48.5 cc/rev | 207 bar |
| 17 | 1-3/4 in | 56.5 cc/rev | 172 bar |
| 20 | 2 in | 64.6 cc/rev | 172 bar |
| Frame Size | Gear Width | Displacement | Maximum Continuous Pressure |
|---|---|---|---|
| 05 | 1/2 in | 20.9 cc/rev | 207 bar |
| 07 | 3/4 in | 31.3 cc/rev | 207 bar |
| 10 | 1 in | 41.8 cc/rev | 207 bar |
| 12 | 1-1/4 in | 52.2 cc/rev | 207 bar |
| 15 | 1-1/2 in | 62.7 cc/rev | 207 bar |
| 17 | 1-3/4 in | 73.1 cc/rev | 207 bar |
| 20 | 2 in | 83.6 cc/rev | 172 bar |
| 22 | 2-1/4 in | 94.0 cc/rev | 172 bar |
| 25 | 2-1/2 in | 104.5 cc/rev | 172 bar |
The maximum continuous pressure depends on the gear width. Please be sure to verify this based on the specific pump configuration before placing an order.
P31 and P51 hydraulic gear pumps are widely used in commercial vehicle hydraulic systems. Typical applications include dump trucks, refuse collection vehicles, roll-off trucks, moving floor trailers, wreckers, and material handling equipment.
When selecting a suitable pump, consider the required flow rate, operating pressure, PTO speed, shaft connection, mounting flange, and hydraulic port configuration. The theoretical flow rate can be calculated using:
Flow Rate (L/min) = Displacement (cc/rev) × Speed (rpm) ÷ 1,000
Actual flow depends on volumetric efficiency and operating conditions. For tandem or multiple-section pumps, the combined flow requirements and drive shaft load must also be considered.
Before replacing an existing P31 or P51 pump, verify the complete model code, gear width, rotation direction, shaft type, and mounting dimensions. Matching displacement alone does not guarantee compatibility.
Proper installation is important for maintaining pump performance and service life. Before installation, confirm the PTO connection, mounting flange, shaft configuration, rotation direction, and hydraulic port arrangement. Ensure that the suction line provides sufficient oil supply and that the hydraulic circuit is clean.
Use suitable hydraulic oil and maintain proper filtration to reduce contamination and wear. During commissioning, check for abnormal noise, oil leakage, unstable pressure, and excessive temperature. Regular inspection of bearings, seals, hydraulic connections, and oil condition helps maintain reliable operation.
Cissoko provides hydraulic gear pump solutions for commercial vehicles, mobile machinery, and industrial hydraulic applications.
For customers looking for P31 or P51 replacement pumps, correct model identification is essential. Our team can help evaluate replacement requirements according to the original pump model, displacement, gear width, shaft connection, mounting flange, rotation direction, and hydraulic port configuration.
Whether you need a replacement for an existing pump, a tandem gear pump assembly, or a hydraulic solution for new equipment, Cissoko can help identify a suitable configuration according to your application requirements.
Please provide the original pump nameplate, product photos, or complete model code to help confirm the correct replacement.
As a customer, you can trust Cissoko Hydraulic for the following reasons:
Our factory has 3 branches,located in Changzhou, Shandong and Zhejiang respectively,covering a total area of 8000 square meters.
Top Leading Hydraulic pump Manufacturer
Our piston pumps, gear pumps, hydraulic cylinders, and other components are built to last. We utilize the latest technology and rigorous testing methods to ensure all products meet international quality standards.
Hydraulic Pump & Hydraulic Piston Pump & Hydraulic Motor & Hydraulic Vane Pump Factorys - Cissoko Hydraulic
We are proud to serve over 60 countries worldwide, providing first-class hydraulic solutions globally. Our products are trusted in regions such as the United States, Germany, Brazil, Russia, and Southeast Asia.
Customized Services:
Need a specific product?
We offer OEM and ODM services, allowing us to customize hydraulic components to your specific needs.
Cissoko Hydraulic is ISO9001 certified, CE certified, and complies with EU RoHS standards. This ensures all our products meet the highest global quality and safety standards. In addition, some of our products are UL certified, further enhancing reliability.
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We provide ongoing technical support and after-sales service to ensure your system always performs at its best.
hydraulic Pump manufacturer - Cissoko Hydraulic
Once your product is manufactured and confirmed with you, it will be packaged and shipped within 6 hours.
By understanding how hydraulic piston pumps work and why Cissoko Hydraulic is the trusted choice for hydraulic components, you can make informed decisions that enhance the performance and reliability of your systems.
