Craftsman Motor Vehicles Maintenance common mistakes
Craftsman Motor Vehicles Maintenance · Understand the traps and how to avoid them.
When asked to identify a hazard in a workshop scenario, candidates list only the obvious machine hazard (rotating belt, hot exhaust) and omit the latent ones such as stored hydraulic pressure, unsecured vehicle on stands, or a live circuit left connected.
Candidates study hazards as a vocabulary list and rehearse definitions of 'mechanical', 'electrical', 'chemical' rather than practising a systematic sweep of an actual task sequence, so recall stops at the first item that fits.
What to do instead
Before answering, run a fixed four-step sweep on the described task: energy sources (mechanical, hydraulic, pneumatic, electrical, thermal, chemical), who is exposed, what controls exist, and what happens if a control fails. Write the list before choosing the option, then match your list to the answers.
Selects a torque figure or fastener grade from memory instead of reading the specification given in the question stem, or applies a dry torque value to a lubricated thread.
Candidates memorise a handful of 'typical' figures and pattern-match the component name, ignoring that the stem supplies the exact grade, thread condition, and wet/dry state that determine the correct value.
What to do instead
Treat every stem as self-contained: underline the grade, thread condition, and units before answering. Remember that lubricated threads reduce friction, so the same clamp load needs a lower torque; if the stem gives a wet condition, reject dry-torque distractors outright.
Diagnoses low oil pressure by naming a single component (usually the pump) rather than ordering checks by cost and accessibility.
Candidates associate symptom with one famous cause, and the pump is the most memorable part of the lubrication system, so it becomes the default answer even when the stem describes a sender, relief valve, or diluted oil.
What to do instead
Answer in the standard sequence: verify the gauge with a mechanical test gauge, check level and condition of oil, check the sender and wiring, then the relief valve and pickup, and only then the pump and bearing clearances. Choose the option that matches the earliest sensible step.
Confuses overheating causes by attributing every overheat to the thermostat, or misreads a cooling-system pressure test by ignoring the specified test pressure and hold time.
Thermostat failure is the most frequently taught cooling fault, and pressure-test numbers look like trivia, so candidates skim them; they also forget that a cold engine with a pressurised system can hide a leak until it warms.
What to do instead
Build a one-page decision table: temperature rises at idle only (fan/clutch), rises at speed (restricted radiator/airflow), rises under load then falls (thermostat sticking), loses coolant with no external leak (head gasket or heater matrix). For pressure tests, quote the stem's pressure and hold time back in your reasoning rather than a memorised figure.
Judges cylinder leakage or compression results without correcting for engine temperature, throttle position, and the number of compression strokes, and treats a single low cylinder as conclusive.
Candidates learn the pass/fail threshold but not the test conditions, so a dry test on a cold engine with the throttle closed is read as a worn engine, and one low reading is reported as a fault instead of a lead.
What to do instead
State the conditions first: engine at operating temperature, throttle wide open, all plugs removed, fixed number of strokes. Then compare cylinders against each other and against specification, and confirm with a wet test and a leakage test to localise the loss (rings, valves, gasket).
Misreads valve clearance or timing results by applying the clearance specification to the wrong measurement point, or ignoring that clearance is set with the engine cold.
Clearance figures are memorised as numbers without the condition attached, and candidates confuse intake and exhaust values or measure at the base circle incorrectly.
What to do instead
Always attach the condition to the number in your notes: 'cold, intake, at base circle'. When a stem gives a hot engine, reject the cold specification. If a valve is noisy, check clearance, cam wear, and oil supply in that order.
Diagnoses a clutch slip or judder as a worn disc without first ruling out the hydraulic release system, cable adjustment, or oil contamination.
The friction disc is the visible wear item and the most memorable, so candidates jump to replacement; they also confuse slip (engine speed rises, road speed does not) with judder (vibration on take-up).
What to do instead
Separate the symptoms explicitly: slip under load, judder on engagement, drag (difficulty selecting gears), noise. For slip, check free play and release bearing clearance, hydraulic actuation, then disc thickness and contamination. Answer with the cheapest test that distinguishes them.
Describes brake bleeding or hydraulic diagnosis without stating the correct sequence and fluid handling, or misattributes a spongy pedal to air when the real cause is a leaking seal, flexible hose expansion, or a faulty master cylinder.
Bleeding order and fluid specification are learned as lists, while fault patterns are learned separately, so candidates cannot link a symptom to the hydraulic circuit; dot-point answers also tempt candidates to skip the sequence.
What to do instead
Learn the circuit as a chain: pedal, master cylinder, lines and hoses, proportioning or ABS unit, calipers, and the correct bleed order from the manufacturer's specification. For a spongy pedal, test for external leaks and hose swelling before assuming air, and always specify fresh fluid of the correct grade and disposal of old fluid.
Reports alignment angles without distinguishing thrust angle, included angle, and setback, and recommends adjustment without checking tyre pressure, ride height, and steering-centre first.
Candidates memorise camber, caster, and toe as three words and treat all alignment readings as independent, so they misread a crooked steering wheel or a dog-tracking vehicle as a simple toe fault.
What to do instead
Before interpreting angles, confirm tyre pressures, load, ride height, and that the steering wheel is centred. Then read thrust angle and setback to decide whether the rear axle is the problem, and only then set front toe last, because toe is the angle that is adjusted after camber and caster.
Diagnoses electrical faults by replacing components instead of measuring voltage drop, and misuses a multimeter by measuring resistance on a live circuit or current in parallel.
Candidates are comfortable with continuity testing and uncomfortable with loaded-circuit measurement, so they substitute parts; meter connection errors come from never having practised the three measurement modes under time pressure.
What to do instead
Use the voltage-drop method: measure across each connection under load, with the circuit energised, and accept a small drop only. Practise the three modes until automatic - volts in parallel, amps in series, ohms on an isolated component - and state which mode you are using in your answer.
Answers preventive-maintenance or inspection questions with a generic checklist rather than the specific interval, measurement, and rejection criterion the question asks for.
Candidates revise inspection as a topic list ('check brakes, check tyres') and never attach limits, so they cannot answer when a component must be taken out of service.
What to do instead
For each inspection item, memorise three things: what is measured, the minimum or maximum limit, and the action when the limit is exceeded. Practise stating them as a single sentence, for example tyre tread depth against the legal minimum and the resulting advice to the customer.
Records a fault as a conclusion ('needs new alternator') instead of a symptom, test, and result, and gives the customer no cost, safety, or follow-up information.
Candidates write answers as they would speak to a colleague, compressing the diagnostic reasoning, and treat customer handling as soft skills unrelated to technical accuracy.
What to do instead
Write every diagnosis in three lines: complaint in the customer's words, test performed with the measured value, and conclusion with the recommended action. Then add what the customer must know: whether the vehicle is safe to drive, what happens if the repair is deferred, and when to return.