708-2K-00112 708-2K-00113 708-2K-00114 Excavator Hydraulic Pressure Pump Komatsu PC800-8 PC850-8 Main Piston Pump

The PC850-8 is a Komatsu large mining/heavy excavator (PC850LC-8 / PC850SE-8 / PC850-8 platform) utilizing a large-displacement variable displacement piston pump system. The hydraulic main pump features a tandem double piston pump configuration (front/rear sections) with substantial displacement, high power output, and represents the most critical high-value component of the machine.

• Weak/slow movement on one pump side: Internal leakage from worn pistons, valve plate, or slippers in that section, resulting in reduced volumetric efficiency
• All functions weak: Insufficient main pump pressure, failed main relief valve pressure setting, or severe pump internal leakage
• Pump abnormal noise/squealing: Insufficient suction or air ingress, contaminated oil, or internal pump wear
• Engine lugging/speed drop under load: Seized power regulator or control spool
• High oil temperature: Severe main pump internal leakage
• Oil leakage: Aged main shaft oil seal, worn end-cover O-rings, or poor case drain
• Jitter/pressure fluctuation: Air in the system, seized regulator, or scored valve plate

• Confirm sub-model: PC850-8 / PC850LC-8 / PC850SE-8
• Confirm configuration: Main pump assembly vs single pump core
• Verify part number: Based on original old part number
• Condition evaluation: Genuine new units are extremely expensive; remanufactured (Reman) units offer common cost-saving; aftermarket compatible units require careful evaluation
• Overhaul parts: Cylinder block, valve plate, piston (slipper), retainer plate, swashplate, main shaft, bearings, seal kit
• After-sales considerations: 6-12 month warranty; fill with hydraulic oil before starting; replace all filters and clean oil tank after repair