Lesson 1Hydraulic system fundamentals: fluid properties, viscosity, temperature effectsGoes over hydraulic system basics for diagnosis, including Pascal’s law, flow versus pressure roles, fluid properties, viscosity index, and how temperature changes affect efficiency, leaks, and part life in Zambian 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 finding valve and actuator faults like sticking spools, internal leaks, and cylinder seal failures, using pressure, flow, and isolation tests to separate mechanical from hydraulic problems in farm 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)Looks at how heat affects hydraulic performance, including thermal breakdown, viscosity loss, and common overheating sources like coolers, fans, and radiators, plus ways to find and fix high operating temperatures in hot climates.
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 checks for hydraulic filters, reservoirs, and breathers, including spotting blocked or collapsed elements, bypass valve work, tank baffling, and air control to prevent aeration, cavitation, and early part 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 right ways to take hydraulic oil samples, check cleanliness levels, find water, air, and sludge, and read lab particle counts to decide when to flush, filter, or change fluid in Zambian farm machines.
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 testing fixed and variable pumps with flow meters and pressure controls, reading flow versus pressure curves, and matching measured output to specs to confirm pump health or spot 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 understanding slow or jerky hydraulic moves that get worse as oil heats up, linking signs to main causes in pumps, valves, actuators, and fluid state for quicker, accurate fixing.
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 check system and relief settings, pilot circuits, and sequence and counterbalance valves, making sure pressures match specs and protecting parts 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 key hydraulic diagnostic tools, like pressure gauge sets, flow meters, temperature probes, and contamination kits, with tips on choice, safe use, calibration, and care for reliable tests.
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 proceduresGives a planned way to decide repair or replace pumps, valves, and cylinders, including cost comparison, downtime effect, rebuild steps, and records for reliable, cost-effective hydraulic fixes.
Evaluating repair versus replacement costsAssessing downtime and machine availabilityJudging core condition for rebuildingPlanning pump, valve, and cylinder overhaulsDocumenting test results and repair history
