Rexroth A4VG250 high pressure variable displacement hydraulic pump

The A4VG250 is a swashplate design, axial piston pump with a variable displacement capability. The "250" refers to its nominal displacement of 250 cm³ per revolution. Designed for closed circuits, it operates at high pressure—typically up to 450 bar (6,525 psi) for peak pressures and 400 bar (5,800 psi) continuously.

Real-World Applications

Due to its high torque density, the A4VG250 excels in sectors where diesel engines power hydrostatic transmissions.

Example 1: Large Crawler Excavators

In a 50-ton excavator, the A4VG250 powers the left and right tracks independently (two pumps for steering). Operators get smooth counter-rotation and hill-climbing torque without overheating.

Example 2: Underground Mining Loaders (LHDs)

Load-haul-dump machines face severe contamination. The A4VG250's pressure-cutoff feature prevents stall under maximum bucket load. Its 400 bar continuous rating handles rock hard spots without bypass relief chattering.

Example 3: Agricultural Self-Propelled Sprayers

A 4WD sprayer uses the pump's EP control for infinitely variable ground speed (0–40 km/h) while keeping engine RPM constant for the PTO-driven spray pump. Result: consistent chemical application regardless of terrain.

Maintenance, Common Failure Modes & Expert Fixes

Even a robust pump fails prematurely if the upstream system is ignored. Here's what experts check.

Charge Pressure Is Everything

The A4VG250 requires a charge pump (typically 15–30 cc/rev) to maintain 20–35 bar of low-pressure feed. Low charge pressure = cavitation = destroyed slippers and valve plate.

Early symptom: The pump whines loudly when driving, but stops under no load.

Contamination Sensitivity

The pump's clearances are around 5–15 µm. ISO 4406 code 18/16/13 is the minimum cleanliness. Anything dirtier leads to:

Sticking control spools

Worn servo pistons

Scoring on the cylinder barrel face

Pro tip: Use a 10 µm absolute β10≥200 filter in the return line and replace it every 500 hours.

Seal and Shaft Failures

The input shaft (often SAE C, D, or E splined) handles high radial loads if belt-driven. Misalignment kills the shaft seal within hours. Always use a flexible coupling and check runout to <0.25 mm TIR.

For more information on the A4VG250 hydraulic pump, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1: Can I replace an A4VG250 with an A4VG180 or A4VG355?

A1:Not directly. The mounting flange (SAE J744, 4-bolt or 6-bolt) differs in size. Also, the A4VG250’s displacement is fixed; a larger pump requires more charge flow and may overload the input shaft torque rating.

Q2:Why does my A4VG250 overheat?

A2: Most common: undersized cooler, worn charge pump (low flow to flush hot oil out of the loop), or excessive case drain pressure (check case drain filter and backpressure <3 bar absolute).

Q3:How to purchase an A4VG250 hydraulic pump?

A3:You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.

Q4:What is the price and delivery time of the A4VG250 hydraulic pump?

A4:The specific price and delivery time will be provided based on the specific model you provide.