1505811 Hydraulic pump price main pump CAT 306D excavator hydraulic pump Rexroth AP2D25

This high-precision heavy-duty hydraulic main pump assembly features a core OEM part number of 150-5811 (1505811), utilizing the renowned Bosch Rexroth AP2D25 series twin-acting swashplate high-pressure piston pump. As the absolute hydrodynamic core of the entire vehicle system, it is specifically engineered for Caterpillar's core medium and small hydraulic excavators, perfectly matching CAT 306D, 307, 308B, and 308C, among other 6- to 8-ton golden flagship models. The product is optimized for high-pressure hydrodynamics based on first principles, ensuring absolute power output reliability under frequent excavation, travel, and slewing compound working conditions. The packaged physical dimensions are approximately 430mm × 260mm × 280mm, with a total net weight of around 32kg. It achieves precise OEM-standard positional alignment.

"Extreme cleaning and torque tightening: Dust removal treatment is required for unpacking and lifting environments. All high-pressure oil pipes and feedback signal pipes must be thoroughly cleaned with specialized cleaning agents before being connected to a new pump. Bolts must be tightened symmetrically and in stages using torque wrenches in strict accordance with the original factory standard torque, to prevent local stress deformation.

Forced oil filling (core pit avoidance): After the main pump is lifted into place and before starting the engine, clean hydraulic oil must be filled from the top of the main pump's air release/oil injection port. It is strictly prohibited to start dry grinding, otherwise the internal rotating plunger component will undergo irreversible physical erosion within 3 seconds of ignition.

Low pressure transition and exhaust: After the first ignition, the engine must be kept idling and running at low pressure for 10-15 minutes for automatic exhaust and thermodynamic adaptation of the system. Normal operating loads can only be gradually applied after the oil temperature and pressure stabilize and all bubbles are cleared."