Topic
Field diagnosis and maintenance
What to measure, when to measure it, and what the reading proves. Noise, contamination, case drain and the habit of testing before replacing.
Articles in this topic (6)
Every article below is written from catalogue data, from the training material and from repair cases we handle.
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.
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…
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…
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…
Excavator Hydraulic System Maintenance and Care Guide: From Daily Inspection to Fault Diagnosis
Technical Guide
A complete guide to excavator hydraulic system maintenance — from daily inspection to systematic fault diagnosis.
How to Extend the Life of Your Excavator Hydraulic Pump
Technical Guide
Practical maintenance tips: early signs of swash plate wear, proper oil filtration, and recommended replacement intervals for K3V/K5V pumps.
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.
K3V140DTP
27–33 t hydraulic excavator
140 mL/r (per pump) · 34.3 MPa
K3V180DT
36–40 t hydraulic excavator
180 mL/r (per pump) · 34.3 MPa
K5V200SH
single pump / front pump of a combined set
200 mL/r · 34.3 MPa
FTD26
13–16 t excavator / drilling rig / crawler crane
Parts that solve this (6)
Catalogue part lines from the same families. Search the full library by part number from the parts library.
2943800424
SET PLATE · pos. 153
2943800488
SET PLATE · pos. 153
29241100-056
SET PLATE · pos. 153
2924110-0049
SET PLATE · pos. 153
2924110-0009
SET PLATE · pos. 153
2923250-0338
PUMP CASING · pos. 271
Machines this applies to (6)
Machine pages that list the units above as fitment, model by model. See every machine →
SANY SY330
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
VOLVO EC300
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
VOLVO EC290B
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
DOOSAN DH300-7
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
HYUNDAI R300LC-7
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
KOMATSU PC300-7
Machine page
Pump, swing motor and travel assembly options for this machine, with the fitment list.
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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…