Product Overview
The P350B578AB12-98 is a cast iron external gear pump from the Parker Hannifin PGP350 series, corresponding to Parker part number 3239529060. This model is a tandem pump configuration, combining a P350 series primary pump with a P315 series secondary pump in series.
The PGP350 series represents Parker’s premium cast iron gear pump line, featuring three-piece cast iron construction and balanced thrust plates. The P350 series covers displacements from 21 to 105 cm³/rev, with a maximum operating pressure of 241 bar (3,500 psi) and speeds up to 2,400 rpm.
The P30/P31, P50/P51, and P75/P76 series belong to Parker’s Commercial product line (formerly Commercial Intertech), holding a dominant position in the North American dump truck and construction equipment markets. P30/P31 displacements range from 16.1 to 64.6 cm³/rev, P50/P51 from 20.9 to 104.5 cm³/rev, and P75/P76 from 33 to 199 cm³/rev, with rated pressures of 172 – 207 bar (2,500 – 3,000 psi) .
Every unit is manufactured to original equipment specifications, ensuring 100% drop-in interchangeability with Parker Commercial, Muncie, Permco, Metaris, and other brand equivalents. Each pump undergoes rigorous 100% simulated duty-cycle testing to validate pressure-flow-efficiency performance curves.
Brand Disclaimer: This product is a high-quality compatible replacement engineered for full interchangeability with Parker Hannifin original equipment. All Parker brand names and model codes are referenced solely to indicate compatibility and interchangeability. This product is manufactured by an independent producer and is not an original Parker product.
Technical Specifications
PGP350 Series（P350B578AB12-98 / 3239529060）
Model Code: P350B578AB12-98 (with P315AEPAB08 secondary)
Parker Part Number: 3239529060
Brand Series: Parker Hannifin PGP350 Series
Product Type: Tandem Fixed Displacement External Gear Pump
Series Displacement Range: 21 – 105 cm³/rev
Maximum Operating Pressure: 241 bar (3,500 psi)
Maximum Speed: 2,400 RPM
Maximum Flow Rate (Series) : 66 GPM (250 L/min)
Volumetric Efficiency: Up to 98%
Housing Material: Three-piece cast iron construction
Thrust Plates: Balanced Thrust Plates
Bearings: Journal Bearings
Rotation Direction: CW / CCW / Bi-Rotational available
Mounting Options: SAE | ISO | DIN
Port Connections: SAE | ISO | NPT | BSPP | ODT
Port Location: Side Ports | Rear Ports
Thru-Drive Capability: Yes
Hydraulic Fluid: Standard Hydraulic Fluid / Phosphate Ester / Water Glycol
Maximum Fluid Temperature: 80°C
Minimum Fluid Temperature: -20°C
Maximum Kinematic Viscosity: 7,500 SUS
Minimum Kinematic Viscosity: 50 SUS
Maximum Weight: 27 kg (60 lb)
Radial Load Capacity: 510 kg (1,125 lb)
Integrated Valve Options: Relief, Load Sense, Priority, Unloader
P30 / P31 Series
Brand Series: Parker Commercial P30/P31
Displacement Range: 16.1 – 64.6 cm³/rev
Operating Pressure: 172 – 207 bar (2,500 – 3,000 psi)
Housing Material: Cast Iron
P50 / P51 Series
Brand Series: Parker Commercial P50/P51
Displacement Range: 20.9 – 104.5 cm³/rev
Operating Pressure: 172 – 207 bar (2,500 – 3,000 psi)
P75 / P76 Series
Brand Series: Parker Commercial P75/P76
Displacement Range: 33 – 199 cm³/rev
Operating Pressure: 172 – 207 bar (2,500 – 3,000 psi)
Key Technical Advantages
1. Three-Piece Cast Iron Construction – Extreme Durability
The PGP350 series features three-piece cast iron construction, providing excellent distribution flexibility and structural rigidity. Delivers extended service life under high-pressure shocks, severe temperature variations, and high-contamination conditions—ideal for backhoe loaders, forestry equipment, and oil & gas applications.
2. Balanced Thrust Plates & Journal Bearings – High Efficiency & Long Life
Integrated balanced thrust plates minimize friction and internal leakage. Paired with journal bearings, friction losses are minimized while extending service life. Volumetric efficiency reaches up to 98%.
3. Integrated Tandem Design for Simplified System Architecture
The P350B578AB12-98 features a tandem configuration (P350 + P315), integrating two independent pump sections into a single compact unit. Delivers two independent oil flows from a single drive input—serving loader arms and backhoe operations simultaneously.
4. Extensive Integrated Valve Options – High System Integration
The PGP350 series supports integration of multiple control valve functions including: Relief, Load Sense, Priority, and Unloader valves. Integrated design reduces component count, eliminates hoses and fittings, and lowers assembly labor costs.
5. Broad Speed & Temperature Operating Range
Supports speeds up to 2,400 RPM with operating temperatures from -20°C to +80°C. Maintains stable flow characteristics from cold start to high-speed continuous duty.
6. Multiple Interface Standards & 100% Drop-In Interchangeability
Available with SAE, ISO, and DIN flanges, shafts, and port configurations. P30/P31/P50/P51/P75/P76 series are 100% interchangeable with Parker Commercial, Muncie, Permco, Metaris, GPM, and other brand equivalents.
7. 100% Simulated Duty-Cycle Testing
Every pump is 100% tested on dedicated hydraulic test benches under simulated real-world operating conditions—validating pressure-flow characteristics and efficiency curves at rated pressure and full speed range—ensuring zero-defect, plug-and-play performance upon installation.
Application Areas
Backhoe Loaders: CASE, New Holland, CNH equipment
Dump Trucks: Body hoist and lower hydraulic systems
Aerial Lifts: Boom elevation and rotation hydraulic systems
Material Handling Equipment: Forklifts, telehandler hydraulic systems
Forestry Equipment: Wood processing and material handling equipment
Mining & Oil & Gas: Mining machinery and oilfield equipment
Vocational & Municipal Vehicles: Tire trucks, salt and sand spreaders
Expert Maintenance Tips
1. Fluid Cleanliness Control
Maintain system fluid cleanliness to ISO 4406 19/17/14 or better. Install a ≤10 μm absolute filtration filter upstream of each inlet port to prevent particle contamination from damaging precision gear pairs, journal bearings, and thrust plates.
2. Inlet Line Requirements
Keep suction lines short and straight with adequate diameter—not less than the port size. Both inlet ports of the tandem pump must be supplied with sufficient flow independently. Recommended suction line flow velocity: ≤1.5 m/s to prevent cavitation from excessive inlet resistance. Inlet pressure must be maintained between 0.8 – 2.0 bar (absolute) .
3. Coupling Alignment Precision
Ensure pump shaft-to-drive shaft coaxiality deviation ≤0.05 mm and angular deviation ≤0.5° during installation. Flexible couplings are strongly recommended. For PTO-driven applications, ensure driveline alignment meets specifications.
4. Radial Load Management
The PGP350 series radial load capacity is 510 kg (1,125 lb) . If the drive involves sprockets or V-belt pulleys, an independent outboard bearing MUST be installed to protect pump shaft bearings.
5. First-Start Priming Procedure
Before initial startup, bleed air through both outlet ports or drain ports separately. Perform 2–3 jog starts with outlets open (no load) until oil fills both pump sections without air bubbles, then connect load circuits for full operation.
6. Viscosity & Temperature Monitoring
Recommended operating viscosity: 50 – 7,500 SUS. Operating temperature range: -20°C to +80°C. During cold starts when viscosity exceeds the recommended range, ensure adequate suction conditions or preheat the fluid.
