CAT 305.5E CAT 305.5E2 235-4254 311-8540 AP2D25 Rexroth Uchida AP2D25 Electronic Control Hydraulic Main Pump Assembly Compatible with Caterpillar Kubota Rexroth

1. Product Overview & Wholesale Price Range

The Rexroth Uchida AP2D25 / AP2D25LV Electronic Control Hydraulic Main Pump Assembly (OEM Part # 235-4254 / 311-8540 / 215-3215 / AP2D25) is a dual axial piston variable displacement pump equipped with proportional solenoid control valves and gear pilot pump, engineered for 5-to-5.5-ton mini excavators operating under continuous trenching, landscaping, and residential earthmoving works.

• Factory Wholesale Price: $1,350 – $2,650 USD (Direct manufacturer pricing — Save up to 50% vs regional dealer markups)
• MOQ & Bulk Discount: 1 Unit (Tiered wholesale discounts available for batch container orders)
• Lead Time: 1–3 business days (Large factory stock ready for immediate worldwide dispatch)
• Warranty: 12 Months full replacement warranty with 100% bench test video proof

2. Application Worksite Checklist (施工场景清单)

Precision-matched electronic displacement control designed to deliver smooth hydraulic power under continuous field operations:

• Urban Infrastructure & Utility Trenching: Fine hydraulic metering for smooth boom and arm excavation in narrow ditches with CAT 305.5E excavators.
• Residential Foundation & Earthmoving: Sustained working pressure under 250 Bar for rapid bucket loading cycles on CAT 305.5E2 excavators.
• Agricultural Irrigation & Farm Maintenance: Thermal-resistant seal groups prevent oil bypass during long continuous operating hours in hot climates.
• Demolition & Small Breaker Operations: Reinforced pump housing protects against severe pressure shockwaves from hydraulic hammer attachments.

3. Hydraulic Main Pump Troubleshooting & Diagnostic Guide (液压泵常见故障排查)

If your CAT 5–5.5 ton mini excavator is exhibiting hydraulic system failure, consult the diagnostic guide below:

• Fault 1: Cold Machine Operates Normally, But Machine Slows Down & Drops Pressure After 1 Hour (冷车正常,热车掉压发慢)
  Root Cause: Thermal expansion wear gap between the piston shoes, cylinder block, and valve plate, causing internal high-pressure oil thermal bypass.
  Solution: Replace with a complete drop-in AP2D25 electronic control main pump assembly (OEM 235-4254) or overhaul the internal rotary group kit.
• Fault 2: Engine Stalls or Overloads When Actuating Hydraulic Boom/Arm (憋车/发动机过载熄火)
  Root Cause: AP2D25 pump regulator proportional solenoid valve spool jammed or pilot pressure relief valve miscalibrated.
  Solution: Recalibrate pump regulator pilot pressure solenoid or replace the complete regulator assembly to restore engine horsepower matching.
• Fault 3: Hydraulic Oil Leakage From Drive Shaft Seal Area (主驱动轴封高压串油漏油)
  Root Cause: Clogged casing drain line causing excessive internal housing backpressure, blowing out the front drive shaft skeleton seal.
  Solution: Flush housing drain lines, replace front drive shaft seal, and check gear pilot pump relief pressure.
• Fault 4: Abnormal Cavitation Noise or Severe Vibration From Main Pump (泵体异响抖动/气蚀)
  Root Cause: Air suction at inlet suction pipe, contaminated hydraulic tank filter, or worn drive shaft bearings.
  Solution: Replace suction line seals, flush hydraulic fluid tank, and replace drive shaft roller bearings.
• Fault 5: Black Metallic Filings Found Inside Hydraulic Tank Filter (油箱内有黑粉或金属屑)
  Root Cause: Severe friction galling on swashplate shoe bronze layer or cylinder block face failure.
  Solution: Flush entire hydraulic piping system, clean main control valve, and install a new AP2D25 electronic control main pump assembly.

4. Hot Machinery Replacement Parts Recommendation (5大品类热门推荐表)

Explore our factory-direct replacement hydraulic components compatible with major global excavator brands:

5. Frequently Asked Questions & Technical Support (QA 问答专区)

Q1: How do I verify if this Rexroth AP2D25 electronic control main pump fits my CAT 305.5E or 305.5E2 excavator?
A: Check your original pump nameplate for OEM part numbers 235-4254, 311-8540, or AP2D25 stamp. You can also send us your machine serial number for instant fitment verification.

Q2: My CAT 305.5E excavator slows down after 1 hour of digging. Will replacing the AP2D25 pump solve this?
A: Yes, thermal slowdown is caused by internal pressure leakage inside the worn pump cylinder block. Installing our new Rexroth AP2D25 electronic control pump restores full hydraulic speed and digging power.

Q3: Is this CAT 305.5E Rexroth AP2D25 electronic control hydraulic main pump bench tested before shipment?
A: Yes, every single AP2D25 pump undergoes a 5-step factory bench test, verifying proportional solenoid response, pressure up to 250 Bar, and volumetric efficiency above 95%. A live test video is provided before shipping.