CAT 306 306E 306E2 458-1033 464-3212 AP2D28 Hydraulic Main Pump Assembly Compatible with Cat

The Cater.pillar CAT 306 / 306E / 306E2 Hydraulic Main Pump Assembly (OEM Part # 458-1033 / 464-3212 / 501-1644 / AP2D28) is a dual axial piston variable displacement pump designed for 6-ton compact excavators operating in municipal earthmoving, utility trenching, and road infrastructure projects.

• Factory Wholesale Price: $1,350 – $2,600 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

Engineered for high volumetric efficiency and rapid response under continuous compact excavator operations:

• Municipal Utility Trenching & Cable Laying: Fine hydraulic flow control for smooth boom and arm excavation in urban narrow ditches with CAT 306E excavators.
• Residential Infrastructure & Foundation Prep: Sustained hydraulic working pressure under 280 Bar during foundation digging and site leveling.
• Road Repair & Landscaping Works: Optimized oil displacement for fast bucket loading and grading cycles on CAT 306E2 excavators.
• Demolition & Concrete Breaking: Heavy-duty pump casing protects against continuous pressure spikes caused by hydraulic breaker attachments.

If your CAT 306 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 AP2D28 main pump assembly (OEM 458-1033 / 464-3212) or overhaul the 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: AP2D28 pump regulator control spool jammed or pilot pressure relief valve miscalibrated.
  Solution: Recalibrate pump regulator pilot pressure 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 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 CAT 306 main pump assembly.

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

Q1: How do I verify if this main pump fits my CAT 306 / 306E excavator?
A: Check your original pump nameplate for OEM numbers 458-1033, 464-3212, or AP2D28 stamp. You can also send us your machine serial number for instant fitment verification.

Q2: My CAT 306E excavator stalls the engine when digging. Will replacing the AP2D28 pump fix this?
A: Yes, engine stalling is usually caused by a sticking pump regulator valve failing to de-stroke under load. Installing our pre-calibrated CAT 306 pump restores smooth engine power matching.

Q3: Is this CAT 306 hydraulic main pump bench tested before shipment?
A: Yes, every single AP2D28 pump undergoes a 5-step factory bench test, verifying pressure up to 280 Bar and volumetric efficiency above 95%. A live test video is provided before shipping.