{"product_id":"cat-416e-422e-428e-434e-piston-pump-3500666-350-0666","title":"CAT 3500666 (350-0666) Piston Pump | Fits 416E 422E 428E 434E Backhoe Loader","description":"\u003ch2\u003eCAT 3500666 (350-0666) Piston Pump | Fits 416E 422E 428E 434E Backhoe Loader\u003c\/h2\u003e\n\u003cp\u003ePremium hydraulic piston pump designed as a direct OEM-compatible replacement for Caterpillar 416E, 422E, 428E, and 434E backhoe loaders. Built to deliver consistent hydraulic performance and long service life in demanding construction, utility, and municipal applications.\u003c\/p\u003e\n\u003ch3\u003eProduct Highlights\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 3500666 \/ 350-0666\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDirect Fit:\u003c\/strong\u003e No modifications required\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh Performance:\u003c\/strong\u003e Meets or exceeds original Caterpillar specifications\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable Construction:\u003c\/strong\u003e Precision-engineered for long service life\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide Application:\u003c\/strong\u003e Suitable for construction, utility, and municipal projects\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 3500666 \/ 350-0666\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Variable Displacement Piston Pump\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand Compatibility:\u003c\/strong\u003e Caterpillar (CAT)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Hydraulic System\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 12 Months\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCompatible Models\u003c\/h3\u003e\n\u003cp\u003eThis piston pump fits the following Caterpillar backhoe loaders:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eCaterpillar 416E Backhoe Loader\u003c\/li\u003e\n\u003cli\u003eCaterpillar 422E Backhoe Loader\u003c\/li\u003e\n\u003cli\u003eCaterpillar 428E Backhoe Loader\u003c\/li\u003e\n\u003cli\u003eCaterpillar 434E Backhoe Loader\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eApplications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBackhoe Loader Lift and Tilt Functions\u003c\/li\u003e\n\u003cli\u003eBackhoe Loader Dig and Swing Circuits\u003c\/li\u003e\n\u003cli\u003eHeavy-Duty Excavation and Loading Operations\u003c\/li\u003e\n\u003cli\u003eConstruction, Utility, and Municipal Projects\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhy Choose This Pump?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eQuality Guaranteed - Manufactured to meet OEM standards\u003c\/li\u003e\n\u003cli\u003eReady to Ship - In stock and available for immediate dispatch\u003c\/li\u003e\n\u003cli\u003eExpert Support - Technical assistance available\u003c\/li\u003e\n\u003cli\u003eCompetitive Pricing - Cost-effective alternative to dealer parts\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What are the symptoms of a failing hydraulic piston pump on CAT 416E, 422E, 428E, or 434E backhoe loaders?\u003c\/strong\u003e\u003cbr\u003eA: Common signs include slow or weak loader lift and tilt response, the backhoe dig function losing power or stalling under load, hydraulic oil overheating during normal operation, whining or knocking noise from the pump area, and visible hydraulic fluid leakage. Backhoe loaders perform dual functions — front loader and rear backhoe — so pump failure affects both loader bucket and digging arm performance simultaneously.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the 3500666 fit all four backhoe loader models?\u003c\/strong\u003e\u003cbr\u003eA: Yes, the 3500666 (350-0666) is designed as a direct OEM-compatible replacement for the CAT 416E, 422E, 428E, and 434E backhoe loaders. These models share the same pump mounting and hydraulic system architecture. Contact us with your backhoe serial number to confirm exact compatibility.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What hydraulic functions does this pump support on a backhoe loader?\u003c\/strong\u003e\u003cbr\u003eA: As the main hydraulic pump, it supplies flow to both front loader circuits (lift, tilt) and rear backhoe circuits (boom, stick, bucket, swing). It also supports auxiliary functions such as stabilizer legs and steering. A failing pump causes weak operation across all these functions — if only the loader or only the backhoe is affected, check for a control valve issue first.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Should I flush the hydraulic system when replacing this pump?\u003c\/strong\u003e\u003cbr\u003eA: Always. Flushing is essential — metal contaminants from the old pump can destroy the new pump within hours. Drain and replace all hydraulic oil, flush the system with clean oil, replace all filters, and refill with fresh Cat HYDO Advanced hydraulic oil. Backhoe loaders work in construction and utility applications where contamination risk is high — a thorough flush is critical.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What type of hydraulic oil is recommended for these backhoe loaders?\u003c\/strong\u003e\u003cbr\u003eA: Caterpillar specifies Cat HYDO Advanced 10W or 30W depending on operating temperature. Backhoe loaders perform varied tasks — digging, loading, lifting — and the hydraulic system operates under frequent load changes. Using non-CAT approved fluids can cause pump wear and void the warranty.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How do I confirm this is the correct pump for my backhoe loader?\u003c\/strong\u003e\u003cbr\u003eA: Check the part number on your current pump — if it reads 3500666 or 350-0666, this is the correct replacement. If the label is worn or missing, provide your backhoe serial number and we will verify compatibility before you order.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does this pump come with mounting hardware or gaskets included?\u003c\/strong\u003e\u003cbr\u003eA: The pump is supplied as a complete unit. Depending on your backhoe configuration, you may need separate mounting bolts, gaskets, or O-rings. Contact us with your serial number and we will confirm exactly what is included and what additional parts you may need for installation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the warranty on this hydraulic piston pump?\u003c\/strong\u003e\u003cbr\u003eA: This piston pump comes with a 12-month warranty covering manufacturing defects. The warranty does not cover damage caused by contaminated hydraulic oil, improper installation, failure to flush the hydraulic system, or using non-CAT approved hydraulic fluids.\u003c\/p\u003e\n\u003cp\u003eLooking for this hydraulic pump? Contact us today for pricing, availability, and lead time information.\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"\/pages\/contact\"\u003eRequest a Quote\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eRelated Products\u003c\/h3\u003e\n\u003cp\u003eExplore our full range of \u003ca href=\"\/collections\/construction-machinery-caterpillar\"\u003eCaterpillar piston pumps\u003c\/a\u003e.\u003c\/p\u003e","brand":"Caterpillar","offers":[{"title":"Default Title","offer_id":46647095918748,"sku":"CAT-3500666","price":0.0,"currency_code":"CNY","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0738\/7385\/0524\/files\/350-06661.jpg?v=1775652268","url":"https:\/\/hepumpstore.com\/products\/cat-416e-422e-428e-434e-piston-pump-3500666-350-0666","provider":"HEPUMP","version":"1.0","type":"link"}