中文
Welcome to Guangzhou HanRui Hydraulic Co., Ltd. We specialize in providing complete Cat 305.5 and 306.5 (CAT 305.5E / CAT 306.5 / CAT 306E) excavator hydraulic main pump assemblies and replacement spare parts, precision-manufactured as heavy-duty aftermarket replacement parts compatible with Cat mini engineering machinery equipment. Built to exact OEM mounting dimensions and high-pressure hydraulic flow specifications, our main pumps restore original digging speed and system pressure for 5-to-6-ton mini excavators at factory-direct pricing.
Heavy-Duty Application & Working Scenarios
Engineered to handle compact excavator digging demands and continuous high-pressure hydraulic output:
- Urban Utility Trenching & Foundation Work: Micro-finished cylinder blocks and swashplates deliver constant working pressure up to 24.5 MPa (245 Bar).
- Landscaping & Road Construction: High volumetric efficiency guarantees rapid boom hoist and bucket stroke compound movements for 5-6 ton excavators.
- Hydraulic Breaker Operations: Reinforced piston shoes and cradle bearings absorb violent hydraulic shock spikes from breaker attachments.
- Fleet Replacement & Overhaul: Pre-calibrated hydraulic main pump assemblies allow direct drop-in bolt-on replacement to minimize site downtime.
Cat 305.5 306.5 Hydraulic Main Pump Fault Diagnosis & Troubleshooting
Facing hydraulic pressure drop or pump leakage on your Cat 305.5 / 306.5 excavator? Over 90% of field repair inquiries involve these main pump failures. Here is how our Cat 305.5 306.5 Hydraulic Main Pump Assembly resolves them:
1. Engine Stalling / Overloading Under Heavy Digging (控泵熄火 / 闷车)
Symptom: Cat 305.5 / 306.5 engine bogs down or stalls completely when pulling heavy digging loads or raising the boom.
Cause: Sticking pump regulators or worn swashplate cradle bearings failing to destroke pump displacement under load.
Solution: Calibrated hydraulic regulators ensure accurate power-matching with the engine to prevent engine stalling.
2. System Pressure Drop & Slow Cycle Speeds (系统掉压 / 动作无力)
Symptom: Slow cylinder attachment movements, weak bucket breakout force, and speed fade as hydraulic oil temperature rises.
Cause: Internal oil bypass caused by micro-abrasion scoring on cylinder block faces or worn piston shoes.
Solution: High-grade alloy cylinder barrels and precision-lapped valve faces eliminate inner slippage and rebuild full operating pressure.
3. Hydraulic Fluid Leakage at Main Shaft & Housing (主泵漏油)
Symptom: Hydraulic fluid leaking around the front drive shaft oil seal or intermediate pump housing joints.
Cause: Shaft seal journal grooving wear or seal lip hardening caused by high case drain backpressure.
Solution: Induction-hardened drive shafts combined with premium high-pressure shaft seals stop oil leaks completely.
4. Pump Cavitation Noise & Severe Vibration (泵体异响 / 抖动)
Symptom: High-pitched whining noise or heavy hydraulic hose shuddering during pump rotation under load.
Cause: Worn piston shoe heads, damaged drive shaft splines, or loose swashplate cradle supports.
Solution: Precision-matched piston shoes and heavy-duty cradle bearings restore smooth, vibration-free hydraulic rotation.
5. Hydraulic Oil Overheating & Thermal Fade (主泵发热高温)
Symptom: Hydraulic tank oil temperature spikes rapidly after 30 minutes of continuous working.
Cause: Excessive friction heat and internal pressure recirculating bypass within worn rotary group components.
Solution: Tight OEM machining tolerances minimize internal friction and heat generation during long working shifts.
Hot Popular Excavator Hydraulic Main Pumps & Spare Parts Catalog
Explore our factory-direct aftermarket catalog for major construction equipment brands:
| Machine Model (型号) | Part Number (零件号) | Component Name (品名) | Compatible Brand (适配品牌) | Target Fault Solved |
|---|---|---|---|---|
| Cat 305.5 / 306.5 / 305.5E | CAT 305.5 Main Pump | Hydraulic Main Pump Assembly | Compatible with Cat | Fixes Engine Stalling & Low Digging Pressure |
| Hitachi 60-6 / ZX60-6 / EX60-6 | Hitachi 60-6 Main Pump | Hydraulic Main Pump Assembly | Compatible with Hitachi | Fixes Engine Stalling & Low Digging Pressure |
| Cat 336GC / 336E | 509-5142 / K5V160DTP | Hydraulic Main Pump Assembly | Compatible with Cat | Fixes Low Digging Pressure & Oil Leakage |
| EX200-5 / EX200-6 / ZX200 | HPV0102 / HPV102 Parts Kit | Main Pump Overhaul Repair Kit | Compatible with Hitachi | Fixes Casing Leakage & Bearing Seat Wear |
| PC300-8 / PC350-8 | 708-2G-00020 / HPV160 | Hydraulic Main Piston Pump Parts | Compatible with Komatsu | Fixes Slow Movement & Pump Noise |
Frequently Asked Questions (Troubleshooting & Fitment)
Q: What is the price range for a complete Cat 305.5 / 306.5 hydraulic main pump assembly?
A: Direct from our Guangzhou factory, the wholesale price range for a complete Cat 305.5 / 306.5 (CAT 305.5E / CAT 306.5) Hydraulic Main Pump Assembly is $680.00 – $1,550.00 USD per set, depending on exact regulator and port configuration. Purchasing directly saves 30% to 50% compared to local OEM dealer prices.
Q: Which mini excavator models are compatible with this Cat 305.5 306.5 main pump assembly?
A: This hydraulic main pump assembly is compatible with 5-to-6-ton Cat mini excavators, including CAT 305.5, 305.5E, 305.5E2, 306, 306.5, and 306E mini excavators.
Q: How do I know if my Cat 305.5 / 306.5 main pump needs a complete replacement?
A: Signs that your Cat 305.5 / 306.5 pump requires complete replacement include: severe engine stalling under digging load, rapid hydraulic speed fade when warm, shaft seal oil leaks into the pilot pump housing, and metal shavings in the case drain filter. Installing a new pre-calibrated pump assembly prevents recurring downtime.
