Lesson 1Hydraulic system fundamentals: fluid properties, viscosity, temperature effectsReviews hydraulic system basics needed for diagnosis, including Pascal’s law, flow versus pressure roles, fluid properties, viscosity index, and how temperature changes affect efficiency, leakage, and component life in farm machinery.
Pressure, flow, and mechanical work basicsPascal’s law in mobile hydraulic circuitsViscosity, VI, and fluid film formationTemperature effects on leakage and wearChoosing correct hydraulic oil gradesLesson 2Valve and actuator diagnosis: spool sticking, internal leakage, cylinder rod seal failureFocuses on diagnosing valve and actuator faults such as sticking spools, internal leakage, and cylinder seal failures, using pressure, flow, and isolation tests to separate mechanical from hydraulic problems in agricultural equipment.
Checking for spool sticking and contaminationTesting for internal valve leakage pathsCylinder drift and piston seal evaluationRod seal inspection and leak confirmationIsolating valve versus actuator problemsLesson 3Heat-related issues: thermal breakdown, viscosity change, overheating sources (radiator, fan, hydraulic oil cooler)Examines how heat affects hydraulic performance, including thermal breakdown, viscosity loss, and common overheating sources such as coolers, fans, and radiators, plus methods to diagnose and correct excessive operating temperatures.
Normal versus excessive oil temperature rangesViscosity change and loss of system stiffnessChecking coolers, fans, and airflow pathsInspecting thermostats and bypass circuitsReducing heat from throttling and leakageLesson 4Filter and reservoir inspection: element condition, bypass valves, breathers and tank designDetails inspection of hydraulic filters, reservoirs, and breathers, including recognising plugged or collapsed elements, bypass valve operation, tank baffling, and air management to prevent aeration, cavitation, and premature component wear.
Inspecting filter elements and housingsChecking filter bypass valve functionEvaluating breather type and conditionAssessing tank baffling and return flowFinding suction leaks at reservoir outletsLesson 5Fluid and contamination checks: oil sampling, particle analysis, water/foam detectionCovers correct techniques for drawing hydraulic oil samples, evaluating cleanliness classes, detecting water, air, and sludge, and interpreting lab particle counts to decide when to flush, filter, or change fluid in farm machinery.
Proper hydraulic oil sampling locationsBottle handling and labeling for the labReading ISO particle count reportsDetecting water, foam, and air entrainmentIdentifying sludge, varnish, and oxidationDeciding when to flush or just filter oilLesson 6Pump testing and flow measurement: variable vs fixed pumps, flow test procedures and expected rangesExplains how to test fixed and variable displacement pumps using flow meters and pressure controls, interpret flow versus pressure curves, and compare measured output to specifications to confirm pump health or detect wear.
Identifying pump type and drive methodInstalling and zeroing a flow meterConducting flow under pressure testsReading flow versus pressure performanceRecognizing cavitation and aeration signsLesson 7Symptoms mapping: causes of slow, jerky actuation under hot conditionsExplains how to interpret slow or jerky hydraulic movements that worsen as oil temperature rises, linking observable symptoms to likely root causes in pumps, valves, actuators, and fluid condition for faster, accurate troubleshooting.
Recognizing heat‑dependent performance changesComparing cold start and hot operating behaviorLinking jerky motion to internal leakage pathsRelating slow actuation to pump wear or cavitationUsing symptom charts for structured diagnosisLesson 8Pressure testing and relief valve checks: setting verification, pilot systems, sequence valvesTeaches safe use of pressure gauges to verify system and relief settings, check pilot circuits, and evaluate sequence and counterbalance valves, ensuring pressures match specifications and protecting components from overload or damage.
Selecting and installing pressure gaugesLocating test ports and safety practicesChecking main system relief valve settingTesting pilot‑operated relief and sequence valvesInterpreting pressure spikes and instabilityLesson 9Tools for hydraulics: flow meter, pressure gauge set, temperature probe, contamination test kitsIntroduces essential hydraulic diagnostic tools, including pressure gauge sets, flow meters, temperature probes, and contamination kits, with guidance on selection, safe use, calibration, and care to ensure reliable test results.
Pressure gauge sets and quick‑couplersPortable flow meters and load valvesInfrared and contact temperature probesContamination test kits and patch testsTool calibration, storage, and safetyLesson 10Decision framework for repairs: repair vs replace pump/valves/cylinders, rebuilding proceduresProvides a structured approach to decide when to repair or replace pumps, valves, and cylinders, including cost comparison, downtime impact, rebuild procedures, and documentation to ensure reliable, economical hydraulic repairs.
Evaluating repair versus replacement costsAssessing downtime and machine availabilityJudging core condition for rebuildingPlanning pump, valve, and cylinder overhaulsDocumenting test results and repair history
