CAT 330B Main Hydraulic Pump 123-2235 184-3955 176-5072 126-2146
2. Basic Product Information
Part Name: Main Hydraulic Pump / Double Axial Piston Pump
Primary OEM P/N: 123-2235 (1232235), 184-3955 (1843955)
Cross Interchange P/N: 176-5072, 126-2146
Compatible Models: CAT 330B, 330B L, 330B LN
Quality Options: Genuine OEM / Professionally Rebuilt / Premium Aftermarket
Net Weight: ~ 165 kg (363 lbs)
Warranty: 12 Months (Free replacement for defective parts)
Stock & Shipping: In stock (Guangzhou). Dispatch in 3-7 days. Air & Sea freight available.
3. Diagnostic Guide: 4 Signs Your CAT 330B Needs a New Main Pump
The main hydraulic pump is the heart of your excavator. If your CAT 330B shows any of the following symptoms, the internal rotary group may be severely worn:
Slow Cycle Times: The boom, arm, and bucket operate much slower than usual, especially when the hydraulic oil heats up.
Engine Lugging or Stalling: If the engine chokes or dies when you apply a hydraulic load, the pump regulator is likely failing to adjust the swashplate angle properly.
Loud Whining or Cavitation Noise: An abnormal, high-pitched screeching from the pump compartment indicates air entering the system or severe internal metal-to-metal friction.
Overheating Hydraulic Oil: Internal leakage inside a worn pump generates extreme heat, causing hydraulic fluid temperatures to spike and reducing machine efficiency.
4. Key Engineering Features
Direct Bolt-on Fitment: Manufactured exactly to Caterpillar blueprints. The mounting flange, splined input shaft, and high-pressure ports perfectly match the original 123-2235 layout.
Variable Displacement Precision: Features an advanced load-sensing regulator that instantly adjusts output flow based on joystick demands, saving fuel and preventing engine overload.
High-Durability Rotary Group: Equipped with forged alloy steel pistons, a hardened copper valve plate, and a high-strength cylinder block to withstand continuous 30-ton class heavy digging.
Rigorous Factory Testing: Every pump is mounted on a hydraulic test bench to verify pressure stability, flow volume, and regulator responsiveness before shipment.
5. Compatibility & Interchange List
Direct Fit Models: CAT 330B, CAT 330B L (Long Carriage), CAT 330B LN (Long Narrow)
Interchangeable Part Numbers: 123-2235 / 1232235, 184-3955 / 1843955, 176-5072 / 1765072, 126-2146 / 1262146
6. Installation & Maintenance Best Practices
Case Priming is Mandatory: NEVER start the engine dry. Fill the main pump casing with clean hydraulic oil through the highest case drain port before cranking.
Complete System Flush: Drain all old hydraulic fluid and flush the tank and lines. Metal shavings from the old pump will instantly destroy the new unit.
Filter Replacement: Install brand-new hydraulic return filters, pilot filters, and clean the suction strainer.
7. Why Choose BELPARTS?
10+ Years of Hydraulic Expertise: Founded in September 2013, Belparts specializes in excavator hydraulic core components.
Global Export Network: Belparts products are shipped to over 150 countries, including North America, Europe, Africa, and Southeast Asia.
Risk-Free Warranty: 1-Year Warranty with free replacement for manufacturing defects.
Air Express (DHL/FedEx): 3-7 days. Sea Freight: 30-45 days for bulk procurement.
8. Technical FAQ
Q1: Are part numbers 123-2235 and 184-3955 the same pump? A: Yes. 123-2235, 184-3955, 176-5072, and 126-2146 are all perfectly interchangeable main pumps for the CAT 330B.
Q2: Does this pump come with regulators and pilot gear pump? A: Yes, the complete assembly includes variable displacement regulators and pilot gear pump, pre-calibrated and ready to install.
Q3: Do you sell internal repair parts? A: Yes. We supply full overhaul seal kits, piston shoes, cylinder blocks, valve plates, and swashplates for the CAT 330B pump series.
Q4: How is the pump packaged? A: Ports are sealed with plastic caps, body coated in anti-rust oil, wrapped in moisture-proof plastic, and secured in a heavy-duty wooden box for safe global transit.
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