Lesson 1Hydraulic system fundamentals: fluid properties, viscosity, temperature effectsGoes over hydraulic basics for diagnosis, including Pascal’s law, flow against pressure roles, fluid traits, viscosity rating, and how heat shifts impact efficiency, leaks, and part lifespan in Namibian farm machines.
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 failureCenters on spotting valve and actuator faults like stuck spools, inner leaks, and cylinder seal breaks, using pressure, flow, and isolation tests to split mechanical from hydraulic issues in farm tools.
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 influences hydraulic work, covering thermal failure, viscosity drop, and usual overheating spots like coolers, fans, and radiators, plus ways to spot and fix high running 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 designOutlines checks for hydraulic filters, tanks, and breathers, spotting blocked or squashed elements, bypass valve function, tank dividers, and air handling to avoid bubbling, sucking, 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 detectionHandles right methods for taking hydraulic oil samples, rating cleanliness levels, finding water, air, and sludge, and reading lab particle numbers to choose flushing, filtering, or oil change in farm gear.
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 rangesShows how to test fixed and variable pumps with flow meters and pressure controls, read flow against pressure graphs, and match output to specs to confirm pump state or find 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 reading slow or jerky hydraulic moves that get worse with oil heat, tying seen signs to likely main causes in pumps, valves, actuators, and fluid state for quicker, right 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 gauge use to check system and relief settings, pilot lines, and sequence/counterbalance valves, making sure pressures fit specs and guarding parts from overload or harm.
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 sets, flow meters, temp probes, and dirt kits, with tips on picking, safe use, calibration, and upkeep for dependable test outcomes.
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 choose repairing or replacing pumps, valves, cylinders, with cost checks, downtime effects, 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
