Topic
Industry, selection and buying
Where the technology came from, what the industry is betting on, and how to specify a replacement unit so that the part number decides - not the price.
Articles in this topic (7)
Every article below is written from catalogue data, from the training material and from repair cases we handle.
Why high-pressure piston pumps are built the way they are - and where they are heading
Industry Insight
Pressure classes climbed from 16 to 35 MPa, and every step was paid for at the slipper and valve plate.
What thirty years of hydraulic industry history means when you buy parts
Industry Insight
Proportional valves and solenoids have been the bottleneck for decades, and the price gap between imported and local parts is a reliability…
Buying a hydraulic unit from abroad: five questions that prevent an expensive mistake
Industry Insight
Nameplate first, pressure class second, rotating group third. Most wrong shipments and early failures come from one of these questions not…
Tube, sandwich, manifold or cartridge: how valve mounting decides serviceability
Technical Guide
How a valve is connected decides how long a repair takes and how many places can leak.
The Development History of Axial Piston Pumps: From Early Hydraulic Transmission to High Pressure, High Efficiency, and Intelligence
Technical Guide
Trace the evolution of the axial piston pump — from the 1905 Williams–Janney prototype to today's high-pressure, intelligent units.
Guangzhou Excavator Parts Market: A Decade of Change, Current Status, and Future Potential
Industry Insight
Guangzhou has grown from the world's largest excavator parts wholesale hub into an export-driven, digitally transforming industrial nexus.
Meet Guangzhou Frank Tech at Bauma China 2026
Exhibition
Visit us at Bauma China 2026, November 24–27.
Diagnosis guides for this topic (10)
When the principle is clear, these are the checklists that start from the symptom.
No pressure / no power at the pump
Pump and pressure supply
No pressure is rarely the pump alone. Use this checklist to separate pump wear from control, suction and relief problems in under an hour.
Noise, vibration and rising oil temperature
Pump and pressure supply
Noise plus heat usually means air, starvation or internal leakage. Which one you have changes what you order.
Metal particles, dirty oil, short component life
Oil, filtration and the system as a whole
Contamination is the number one cause of repeat failures. Here is what to do after a failure so the new pump is not destroyed by the old…
Engine stalls or smokes under load
Pump and pressure supply
When the engine pulls down, the pump is usually asking for more torque than the engine can deliver.
Oil temperature keeps rising
Oil, filtration and the system as a whole
Over-temperature thins the oil and shortens seal life, so every function weakens.
Foam or milky hydraulic oil
Oil, filtration and the system as a whole
Foam means air, milkiness means water, and both destroy the lubrication film.
Case drain flow above specification
Pump and pressure supply
Case drain flow shows how worn a pump or motor is without removing it. Here is how to measure it so the number actually means something.
Machine slow or noisy when cold
Oil, filtration and the system as a whole
In low ambient temperatures the oil is the problem, not the pump.
Machine weak when it is hot
Oil, filtration and the system as a whole
In high ambient temperatures the hydraulic system runs near its thermal limits.
Repair the pump or replace it
Oil, filtration and the system as a whole
The decision follows measurable evidence, not the age of the machine. Work through these six points and the answer is usually obvious.
Units we supply for this topic (4)
Catalogue-verified units whose internals are the ones described above.
K3V63S
6–10 t hydraulic excavator and industrial open circuits
63 mL/r · 34.3 MPa
K5V80S
6–10 t hydraulic excavator and industrial open circuits
80 mL/r · 34.3 MPa
K3V112S
10–12 t excavator and industrial open circuits
112 mL/r · 34.3 MPa
K5V200DTH
40–45 t hydraulic excavator
200 mL/r (per pump) · 34.3 MPa
Parts that solve this (6)
Catalogue part lines from the same families. Search the full library by part number from the parts library.
2953802048
CHECK VALVE ASS'Y · pos. 041
2953802049
CHECK VALVE ASS'Y · pos. 042
2933180-0416
CHECK VALVE ASS'Y · pos. 042
2943800424
SET PLATE · pos. 153
2943800488
SET PLATE · pos. 153
29241100-056
SET PLATE · pos. 153
Machines this applies to (6)
Machine pages that list the units above as fitment, model by model. See every machine →
DRILLING RIGS
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
SANY SY485
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
VOLVO EC460
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
VOLVO EC480
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
DOOSAN DH500
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
KOMATSU PC450
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
Other topics
Components and valves
Spools, pilot stages, windows and flow forces: why a valve behaves the way it does - and why two valves that look the…
Systems and control
Power elements and the loads they drive: matching, speed control, closed circuits, damping and the numbers that decide…
Field diagnosis and maintenance
What to measure, when to measure it, and what the reading proves.