Diagnosis area
Pump and pressure supply
Pressure, delivery, wear and the pump-engine match: the guides that start at the source of the oil.
Guides in this area (4)
Each guide lists the checks in the order a workshop should work through them, what each result means, and which parts usually solve it.
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.
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.
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.
The principle behind these symptoms (9)
Reading the mechanism first usually shortens the checklist.
Measure before you replace: reading a valve load flow curve, and why you must test hot
Technical Guide
A worn pump and a worn valve look identical on site. The load flow curve plus two measurements taken hot will tell them apart before you…
How clean does hydraulic oil need to be? Targets by system type
Technical Guide
Roughly 80% of hydraulic failures start at the oil supply. Here are the particle-size targets by system type, and where contamination…
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.
Why the levers feel heavier on some machines: flow forces, and what they cost
Technical Guide
Every metering edge pushes back on its spool. That force grows with flow and pressure, so it decides lever effort, pilot pressure - and how…
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.
Hydraulic noise: what the sound tells you, and the order to check it
Technical Guide
Fluid noise and mechanical noise sound different. Pick the frequency band, then work the checks in order: suction, settings, mounts, case…
Force against speed: matching the power element to the load, and why oversizing cooks the oil
Technical Guide
Matching means pressure times flow on the hydraulic side equals force times speed on the load side.
Flow gain, pressure gain and load matching: why a bigger pump is not faster
Technical Guide
Flow gain and pressure gain set sensitivity, stiffness and heat. How to read a valve pressure-flow curve, match a pump to the work it does…
Test before you believe: what simulation gets right, what it cannot, and why you must test hot
Technical Guide
Models get flow right and pressure wrong - and oil viscosity changes twelve-fold across the working range.
Units we supply for this topic (5)
Catalogue-verified units whose internals are the ones described above.
K3V112DTP
20–25 t hydraulic excavator
112 mL/r (per pump) · 34.3 MPa
K5V140DTP
27–33 t hydraulic excavator
140 mL/r (per pump) · 34.3 MPa
K5V140S
10–12 t excavator and industrial open circuits
140 mL/r · 34.3 MPa
K5V200DTH
40–45 t hydraulic excavator
200 mL/r (per pump) · 34.3 MPa
K3V180S
industrial open circuits
180 mL/r · 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.
3853802464
PISTON ASS'Y · pos. 011
2924530-0424
PISTON ASS'Y · pos. 011
29245300460
PISTON ASS'Y · pos. 011
29245300462
PISTON ASS'Y · pos. 011
2924530-0735
PISTON ASS'Y · pos. 011
2924530-0462
PISTON ASS'Y · pos. 011
Machines this applies to (6)
Machine pages that list the units above as fitment, model by model. See every machine →
SANY SY215
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
SANY SY225
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
VOLVO EC210B
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
VOLVO EC210D
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
DOOSAN DH220-5
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
HYUNDAI R220-5
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
Other diagnosis areas
Swing, travel and drive assemblies
Motor and reduction-gear complaints: slow swing, weak travel, run-away, noise and metal in the gear oil.
Boom, arm and cylinder functions
The working functions: drift, creep, jerky movement and every-function-at-once complaints.
Valve and pilot control
Spools, pilot pressure, proportional solenoids and pressure transients: the control layer between lever and load.
Oil, filtration and the system as a whole
Oil condition, water and air, cleanliness, climate and the system-level decisions that follow.