Description
Tatan Machinery supplies 100% Brand New KMX32NB main control valve assemblies (OEM reference: 428-2749 / 4282749) for Caterpillar 336E and 336E L hydraulic crawler excavators. Serving as the primary hydraulic distribution brain of the excavator, this complete valve block regulates main pump flow to the boom, arm, bucket, swing, and travel circuits. Manufactured to strict OEM metallurgical tolerances with micro-lapped spools, each assembly is 100% factory bench-tested for spool bypass leakage and relief pressure hold. This page provides verified technical specifications, field failure diagnostic criteria, installation procedures, and direct procurement support.
Supplier Information & Build Status
| Supplier: | Tatan Machinery (Professional Excavator Parts Supplier) |
| Product Category: | Main Control Valve Assembly / Hydraulic Parts |
| Valve Series: | KMX32NB Multi-Section Hydraulic Control Valve |
| OEM Reference: | 428-2749 (Alt: 4282749) |
| Product Condition: | 100% Brand New (Zero Hours, Complete Assembly with Pilot Logic Blocks & Relief Cartridges) |
| Other Parts Status: | All our hydraulic pumps, control valves, and travel motors are 100% Brand New. Only diesel engines are remanufactured. |
| Target Machine Brand: | Caterpillar Excavator Parts |
🏢 Tatan Machinery Hydraulic Staging & Warehouse Facility
Physical inventory storage, hydraulic valve block staging, and pre-export testing facility:
📹 Live Control Valve Inspection Video
Watch our workshop technician verify valve ports, relief cartridges, and casting stamps:
Physical inventory — ready for global crating. Video calls and warehouse visits welcome.
Technical Specifications
| Parameter | Specification Data |
|---|---|
| Valve Model | KMX32NB Series Proportional Spool Valve |
| Main Circuit Rated Pressure | 34.3 MPa (350 bar / 5,076 PSI) / Heavy Lift: 37.3 MPa |
| Maximum Rated Flow | 2 × 280 L/min (Dual Main Pump Flow Integration) |
| Spool Construction | Hardened Alloy Steel Spools with Micro-Finished Clearance |
| Pilot Control Pressure | 3.9 MPa (39 bar / 565 PSI) Standard Pilot Input |
| Total Assembly Weight | Approx. 235 kg (518 lbs) Complete Monoblock/Sectional Cast |
| Standard Machine Match | Caterpillar 336E / 336E L Heavy Excavators |
When to Replace the Main Control Valve on CAT 336E: Field Symptoms
The KMX32NB control valve operates under continuous high pressure in 36-ton excavators. When internal contamination or metal galling occurs, rebuilding in the field is rarely successful. Replace the complete assembly under these conditions:
- Boom Drift & Arm Drop Under Load: Heavy internal spool-to-bore bypass leakage caused by hydraulic contamination. When holding a suspended load, the boom or stick slowly sinks, creating severe jobsite safety hazards.
- Spool Sticking & Sluggish Combined Actions: Metal particles scoring the valve bore, causing spools to bind. The excavator hesitates, jerks, or fails to compound swing and boom-up simultaneously.
- Main Circuit Overheating & Pressure Relief Breakdown: Blown internal logic check valves or eroded main relief seats continuously dumping high-pressure oil to tank, causing hydraulic oil temperature to exceed 90°C within 30 minutes.
- Internal Valve Body Casting Washout: High-velocity oil erosion washing out internal gallery sealing lands. Resealing with new O-rings fails to stop internal pressure crossover between pump 1 and pump 2 circuits.
Workshop Testing Standards (Pre-Delivery Inspection)
Every 100% Brand New KMX32NB control valve undergoes rigorous hydraulic bench testing before release:
- High-Pressure Relief Valve Setting Check: Main relief and port overload relief valves calibrated to exact Cat 336E factory specifications (34.3 / 37.3 MPa).
- Spool Bypass Leakage Rate Test: Pressurizing individual circuits to measure internal oil slippage past closed spools, guaranteeing zero cylinder drift.
- Pilot Signal Response Verification: Testing pilot spool actuation stroke and return spring centering under standard pilot pressures.
- Anti-Drift Check Valve Sealing Test: Verifying tight closure of boom and arm holding valves to eliminate un-commanded cylinder movement.
- Thread & Port Integrity Inspection: Gauge-testing all main flange split-flange bolt holes (SAE Code 62) and pilot line ports to ensure leak-free field hose hookup.
📹 Live Control Valve Inspection Video
Watch our workshop technician verify valve ports, relief cartridges, and casting stamps:
✓ Real physical unit filmed at Tatan Machinery workshop
Export Heavy-Duty Packaging Process
Precision-machined spools can be ruined by a single spec of sand. We enforce clinical packaging standards:
- 100% Sealed Steel Port Caps: Every SAE flange port, pilot port, and drain opening is sealed with heavy-duty metal blanking plates and o-ring plugs.
- Anti-Corrosion VCI Wrapping: The valve block is sprayed with water-displacing protective oil and sealed inside vapor-corrosion-inhibitor (VCI) plastic film.
- Shock-Mounted Internal Framing: The heavy 235 kg cast body is anchored into custom structural timber cradles to absorb ocean vibration.
- Solid ISPM 15 Export Wooden Box: Fumigation-free plywood box reinforced with multi-banded high-tensile steel strapping.
Actual sealed port caps and heavy-duty crating for KMX32NB control valve
Global Shipping & Customs Documentation
Direct international dispatch tailored for construction contractors and parts distributors:
- Emergency Machine Down Air Cargo: Fast air express via DHL Aviation, FedEx Freight, or international airlines within 3–7 business days.
- Consolidated Ocean Sea Freight (LCL / FCL): Direct containerized shipping to worldwide commercial ports.
- Clean Customs Clearance Paperwork: Commercial Invoices with correct HS Code (8481.20 – Hydraulic Valves), Packing Lists, and Certificates of Origin for tariff optimization.
Container loading and air freight dispatch supported by global logistics partners
Critical Installation Guidelines (CAT 336E Hydraulic Technician Checklist)
To prevent instant contamination and spool seizure in your brand-new valve assembly, technicians MUST adhere to these field rules:
- MANDATORY: Drain & Clean Hydraulic Oil Reservoir: If the previous valve failed due to pump disintegration or cylinder seal failure, metal debris coats the bottom of the hydraulic tank. You MUST drain the tank, wipe out sludge with lint-free towels, and install brand-new suction and return filter elements!
- Chemical Flush Main Pressure Lines: Flush the steel hardlines between the SBS140 main pump and the KMX32NB valve block before making final connections. A single trapped particle will jam a brand-new spool instantly!
- Pre-Fill Pilot Filter & Lines: Prime the pilot control circuit with clean ISO VG 46 hydraulic oil. Air trapped in pilot lines causes jerky joystick response and dangerous pressure spikes.
- Flange O-Ring Seating Check: Inspect all SAE split-flange O-ring grooves. Ensure O-rings are lubricated with clean hydraulic oil and torqued evenly in cross-pattern to prevent high-pressure blowout.
- Initial Relief Pressure Verification: Upon startup, operate the boom, arm, and travel at low idle. Hook a 60 MPa pressure gauge to the main pump pressure test port to verify factory relief pressure before placing machine under heavy digging load.
Buyer Frequently Asked Questions (Purchasing FAQ)
Q: Is this KMX32NB control valve brand new or remanufactured? Does it include relief valves?
A: This main control valve assembly is 100% Brand New with zero operating hours. It comes completely dressed and pre-assembled with main relief valves, port overload relief valves, anti-drift holding valves, and pilot logic manifold blocks. It is a complete drop-in unit ready for immediate hydraulic plumbing.
Q: Are your hydraulic pumps and other products brand new as well?
A: Yes. All our hydraulic pumps, main control valves, final drive travel motors, and swing motors are 100% Brand New. Only our heavy diesel engine assemblies on this site are professionally remanufactured. You can order with absolute confidence in factory-new metallurgical reliability.
Q: My CAT 336E has auxiliary hydraulic piping (hammer / shear circuit). How do we confirm port matching?
A: Caterpillar 336E excavators can feature standard single-action auxiliary spools or dual-flow high-pressure combination circuits. Send your machine’s 17-digit PIN number from the cab tag and clear photos of your current control valve top port layout to Gavin. We cross-verify the exact hydraulic schematic in the official Caterpillar parts database within 10 minutes.
Q: Can I see live photos and serial tags of the exact valve assigned to my order before paying?
A: Absolutely yes. Transparency is our core commitment. Prior to balance payment and dispatch, we send clear high-resolution photos and video showing the stamped valve body numbers, port sealing plugs, relief valve cartridges, and the export wooden box crating process.
Q: What happens if the valve crate is damaged during sea freight, and what customs documentation is supplied?
A: Every shipment from Tatan Machinery is covered by full commercial marine cargo insurance. The valve block is sealed with heavy steel plates and bolted into an ISPM 15 solid wooden crate. We supply commercial invoices with accurate HS Codes (8481.20 – Valves for Oleohydraulic Transmission), packing lists, and Certificates of Origin for smooth customs clearance at your destination port.
🔗 Frequently Purchased Together with CAT 336E Main Control Valve:
- DIESEL ENGINE:
Caterpillar C9.3 Diesel Engine Assembly for CAT 336E (379-3736)
Remanufactured - HYDRAULIC PUMP:
SBS140 Main Hydraulic Pump Assembly for Caterpillar 336E
100% Brand New - SWING MOTOR:
M5X180 Swing Motor Assembly for Caterpillar 336E
100% Brand New - BRAND CATALOG:
View All Caterpillar Excavator & Heavy Equipment Parts Collection
Get Wholesale Factory Quote for KMX32NB 428-2749 Control Valve
Looking for direct factory pricing, stock availability, or technical verification for Cat 336E control valves? Contact senior specialist Gavin now!
💡 Fast Quote: Send your machine serial number or old valve nameplate photos for an accurate match within 10 minutes!
* Note: Wholesale Reference Price Starts From $300.00. Please contact Gavin for a final customized quote based on freight destination and configuration.
* Note: Wholesale Reference Price Starts From $300.00. Please contact Gavin for a final customized quote.
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