A8VO28SR4/60R3-NZG05K02 Rexroth Pump 350Bar

Product Overview

The A8VO28SR4/60R3-NZG05K02 is a high-pressure double variable displacement bent-axis piston pump engineered on the Bosch Rexroth A8VO Series 60 architecture. Designed for compact to mid-sized crawler excavators and heavy mobile hydraulics, this pump covers the broader A8VO range (including A8VO28, A8VO55, A8VO80, A8VO107, A8VO140, A8VO160, and A8VO200) and provides 100% direct drop-in interchangeability with OEM pumps. Every unit undergoes 100% full-load simulated factory testing prior to dispatch, guaranteeing precise dual-circuit power balance, high volumetric efficiency, and exceptional durability under severe working conditions.

Technical Specifications

• Primary Model Code: A8VO28SR4/60R3-NZG05K02 (Covers A8VO Series Platform)

• Brand Platform: Bosch Rexroth A8VO Series 60

• Pump Design: Dual-Circuit Bent-Axis Axial Variable Double Piston Pump

• Displacement: 28 cm³/rev + 28 cm³/rev (Twin Circuit)

• Rated Continuous Pressure: 350 bar (5075 psi)

• Peak Operating Pressure: 400 bar (5800 psi)

• Maximum Drive Speed: 3100 rpm

• Control System: SR Summation Pressure Control with Hydraulic Overriding

• Direction of Rotation: Right-hand (R3 / Clockwise)

• Unit Weight: Approx. 58 kg

Key Technical Advantages

• Bent-Axis Spherical Valve Plate Technology: Features tapered pistons and a spherical control lens, minimizing friction radiuses and delivering volumetric efficiency above 93% under continuous 350 bar operating loads.

• SR Cross-Sensing Power Control: Integrated dual-circuit power regulator dynamically matches hydraulic torque demand to engine output, preventing engine stalls while optimizing machine operational speed and fuel economy.

• 100% Direct Drop-in Fit: Flange mounting patterns, spline shafts, main pressure ports, and pilot control connections match original Bosch Rexroth and OEM specifications exactly for seamless replacement without modifications.

• 100% Factory Simulated Testing: Dynamically tested under full continuous pressure and peak RPM on automated test benches to verify twin-circuit flow synchronization, case drain leakage, and zero external leakage.

Application Areas

• Excavation Machinery: Primary main hydraulic pump replacement for 6 to 10-ton crawler and wheeled excavators.

• Heavy Mobile Hydraulics: High-pressure power source for compact drilling rigs, material handlers, and specialized forestry equipment requiring dual independent hydraulic circuits.

Expert Maintenance Tips

Flush the main hydraulic circuit thoroughly and replace all system filters prior to mounting the pump. Maintain oil cleanliness strictly at ISO 18/16/13 (NAS Class 8) or cleaner using ISO VG 46/68 anti-wear hydraulic oil. Always pre-fill the pump housing completely with clean hydraulic oil through the highest case drain port before initial start-up, performing brief engine cranking cycles to bleed trapped air and avoid dry friction damage to internal components.