Komatsu PC35MR-2 Main Hydraulic Pump Assembly – HPV35 (OEM 708-1S-00021)

Tatan Machinery supplies 100% Brand New variable displacement axial piston main pump assemblies (OEM part numbers: 708-1S-00021 / 708-1S-00020, interchangeable with 708-1S-00022 / 708-1S-11212) engineered for Komatsu PC35MR-2, PC35MR-3, and PC30MR-2 short-tail mini excavators. Powered directly by the Komatsu 3D88E diesel engine, this HPV35 series tandem pump integrates load-sensing (LS) and pressure-cutoff (PC) control valves to deliver smooth multi-spool hydraulic proportional flow to the 709-70-51200 main control valve. Backed by our 12-Month Comprehensive Replacement Warranty, each assembly is completely bench-tested for volumetric displacement, swashplate servo response, and case-drain sealing.

Supplier Information & Build Status

When to Replace the Hydraulic Pump on Komatsu PC35MR-2: Field Diagnostics

The Komatsu PC35MR-2 relies on high-pressure piston flow to operate in tough trenching. Operating under high heat in tight zero-tail compartments frequently triggers specific catastrophic failure:

• LS Servo Piston Varnish Sticking & Engine Bog-Down: Extreme hydraulic oil temperatures (>85°C) deposit varnish on the tiny load-sensing (LS) servo piston. When digging begins, the pump fails to destroke, overloading the 3D88E engine and causing immediate stalling (heavy black exhaust smoke).
• Slipper Shoe Detachment & Piston Swashplate Gouging: High-frequency hydraulic hammering shocks pull the bronze slipper shoes loose from the steel piston ball-heads, severely gouging the swashplate cradle and shearing internal drive components.
• Severe Volumetric Loss When Warm (Hot Digging Weakness): Scored valve plate surfaces allowing high-pressure oil to slip past the cylinder block into the case drain. Digging speed and tracking speed slow to a crawl once oil reaches operating temperature.
• Cavitation Screeching & Hydraulic Oil Aeration: Suction flange O-ring failure or clogged suction strainers pulling air into the rotating groups, generating deafening whine and foaming the hydraulic tank.

Workshop Bench Testing & 12-Month Warranty Guarantee

Every 100% Brand New 708-1S-00021 hydraulic pump supplied by Tatan Machinery comes backed by a 12-Month Comprehensive Replacement Warranty. Before export packaging, our technicians complete a 5-point quality validation:

1. Full Working Pressure Continuous Bench Hold: Loaded to 26.5 MPa (270 bar) continuous pressure on our digital hydraulic test stand to verify body casting integrity and port relief seal tightness.
2. LS & PC Regulator Curve Calibration: Negative flow control curves and load-sensing differential pressures (ΔPLS = 2.0 MPa) calibrated strictly to factory Komatsu specifications.
3. Case-Drain Internal Slippage Measurement: Precision flow-meter measurement at working oil temperature (55°C) to ensure internal slippage is strictly within OEM limits (<2.5 L/min).
4. Dual-Pump Flow Balancing Verification: Testing flow parity between front and rear pump sections to guarantee straight-line excavator tracking without steering pulling.
5. Front Shaft Seal Air Decay Test: 1.5 bar pneumatic air hold test on the front shaft seal cavity to ensure zero oil migration into the 3D88E engine bellhousing.

Export Heavy-Duty Packaging Process

Precision axial piston assemblies require complete protection against airborne moisture and rough cargo handling:

• 100% Sealed Metal/Threaded Port Plugs: Main suction flange, dual pressure outlets, LS signal ports, and case drain port sealed with heavy-duty O-ring blanking plugs.
• Anti-Corrosion VCI Protective Wrap: Input spline shaft and unpainted mounting flanges coated with rust-inhibiting grease and vacuum-sealed in VCI protective foil.
• Custom Molded Foam / Structural Timber Base: The pump is securely positioned in shock-absorbing contoured cushioning within the crate.
• ISPM 15 Fumigation-Free Solid Plywood Box: Sealed export crate banded with heavy galvanized steel straps.

Actual sealed port caps and heavy-duty crating for 708-1S-00021 hydraulic pump

Global Shipping & Customs Documentation

Fast, reliable dispatch tailored for commercial contractors and parts wholesalers worldwide:

• 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 (8413.60 – Hydraulic Piston Pumps), Packing Lists, and Certificates of Origin for tariff optimization.

Container loading and air freight dispatch supported by global logistics partners

Critical Installation Guidelines (PC35MR-2 Pump Mechanic Checklist)

To prevent instant dry-run failure and protect your 12-month warranty, technicians MUST adhere to these critical procedures:

1. MANDATORY: Pre-Fill Pump Casing via Top Drain Port: Prior to starting the engine, remove the top case-drain plug on the pump body and pour clean ISO VG 46 hydraulic oil directly inside until the casing overflows. Starting a dry piston pump will ruin the brass slipper shoes in under 5 seconds!
2. Drain & Chemically Wash Hydraulic Reservoir: If the previous pump suffered catastrophic internal breakdown, bronze glitter coats the bottom of the hydraulic tank. You MUST drain all old oil, clean the tank with lint-free towels, and install brand-new suction and return filter cartridges!
3. Check LS Pilot Sensing Line Connection: Ensure the tiny Load-Sensing (LS) pilot signal hose from the 709-70-51200 control valve is connected to the correct regulator port. Swapping the pilot and drain hoses will lock the pump into zero-stroke mode!
4. Inspect Flywheel Flexible Damper Coupling: Check the plastic/rubber drive coupling on the 3D88E engine flywheel. Replace cracked, heat-hardened couplings to eliminate torsional vibration that shears input splines.
5. De-Aerate and Run at Low-Idle for 15 Minutes: Crank the engine with the fuel shut-off solenoid disconnected to circulate oil. Then start and run at low idle (800 RPM) for 15 minutes without touching joysticks to allow all trapped air to vent back to tank.

Buyer Frequently Asked Questions (Purchasing FAQ)

🔗 Frequently Purchased Together with Komatsu PC35MR-2 Main Hydraulic Pump:

• DIESEL ENGINE:
  Komatsu PC35MR-2 3D88E Diesel Engine Assembly (22F-01-21101)
  Remanufactured
• MAIN VALVE:
  CLSS Main Control Valve Assembly (709-70-51200) for Komatsu PC35MR-2
  100% Brand New
• SWING MOTOR:
  Hydraulic Swing Motor Assembly for Komatsu PC35MR-2
  100% Brand New
• FINAL DRIVE:
  Final Drive Travel Motor (20T-60-71120) for Komatsu PC35MR-2
  100% Brand New
• BRAND CATALOG:
  View All Komatsu Excavator & Heavy Equipment Parts Collection

Get Wholesale Factory Quote for PC35MR-2 Main Pump 708-1S-00021

Looking for direct factory pricing, stock availability, or 12-month warranty terms for Komatsu PC35MR-2 main pumps? Contact senior specialist Gavin now!

💡 Fast Quote: Send your machine serial number or current pump photos for an accurate match within 10 minutes!