HGV Maintenance and Inspection week 2

Vocabulary flashcards covering HGV battery maintenance, vehicle lighting regulations, tachograph legalities, powertrain lubrication, and chassis systems.

Twin Battery Series Wiring (HGV)

A configuration where two $12\,\text{V}$ batteries are wired in series using a jumper wire between two terminals to produce $24\,\text{V}$, with one battery providing the live connection and the other providing the earth.

Lead-Acid Battery Electrolyte

A corrosive liquid inside lead-acid batteries that burns skin, eyes, clothing, and paintwork, and releases an explosive mixture of hydrogen and oxygen gas during charging and discharging.

Battery Disconnection Sequence

The removal procedure requiring the negative (ground) terminal to be disconnected first, followed by the positive (live) terminal.

Battery Connection Sequence

The refitting procedure requiring the positive (live) terminal to be connected first, followed by the negative (ground) terminal.

State of Charge (SOC)

A measure of how charged or discharged a battery is (not its total capacity), indicated by an open-circuit voltage of $12.65\,\text{V}$ when fully charged and evaluated by measuring electrolyte density using a bulb-type hydrometer or refractometer.

H4 Headlight Bulb

A $3$-pin headlight bulb consisting of one earth pin and two live pins for dipped and main beams, operating at $55\,\text{W}$ for dipped beam and $60\,\text{W}$ for main beam.

H7 Headlight Bulb

A $2$-pin bulb commonly used in vehicle dipped beam headlight assemblies.

Stop and Tail Bulb

A $21\,\text{W}$ twin-filament bulb designed so that one filament operates the sidelight and the other operates the brake light.

Direction Indicator Inspection Criteria

Inspection standards requiring amber light on vehicles first used after 1 January 1936, a flash rate exceeding $60$ flashes per minute, and at least $50\%$ of bulbs working if more than one bulb is fitted.

Daytime Running Lamps (DRLs)

Exactly two white forward-facing original equipment lamps fitted to vehicles registered from 1 March 2018, which must not operate when the parking brake is applied or the engine is off, and automatically illuminate if manually switched off once speed exceeds $10\,\text{km/h}$ or distance exceeds $100\,\text{m}$.

Smart 1C Tachograph

A recording unit required on vehicles registered from 15 June 2019 that incorporates stringent sealing requirements, periodically records GPS coordinates, and transmits select data to short-range receivers.

Tachograph Calibration

A statutory requirement carried out upon installation and at least every $2\,\text{years}$ (or when tyre size or registration numbers change), documented on an inspection plaque fitted to the driver's side (O/S) door shut.

Analogue Tachograph Full Inspection

A comprehensive recording equipment inspection required $6\,\text{years}$ after the original installation date and every $6\,\text{years}$ thereafter.

Engine Oil Viscosity

A measurement of an engine oil's resistance to flow at specified temperatures, denoted by a cold/winter start-up flow rating preceding 'W' and a second number defining flow at normal operating temperatures.

Inline Fuel Filter

A non-interchangeable plastic or metal fuel unit featuring tube connectors at each end that allow flexible fuel lines to route straight through.

Cartridge-Type Fuel Filter

A fuel filter assembly featuring a plastic housing and a removable bowl holding a replaceable filter element, typically serviced every $30{,}000\,\text{miles}$ or $2\,\text{years}$.

Fuel Filter Micron Rating

A standardized quantification of a filter medium's ability to trap and extract particulate matter of a designated size or larger from fuel flow.

Filter Efficiency

A retention measurement comparing the number of particles stopped by a filter against the total number of particles attempting to pass through the filter media.

Automatic Transmission Fluid (ATF)

A fluid typically dyed red or green to differentiate it from engine oil, formulated for torque converter function, valve operation, cooling, lubrication, and brake band friction.

Extreme Pressure (EP) Oils

Mineral- or synthetic-based multigrade lubricants containing anti-foaming agents, rust inhibitors, and extreme pressure additives designed to protect heavily loaded differential gear sets from tooth wear.

Air Dryer Filter Cartridge

A chassis component within the air brake assembly designed to remove moisture, compressor oil, and aerosols from compressed air to prevent freezing and brake failure.

Power Steering Bleeding

A procedure conducted after opening hydraulic steering lines to the atmosphere, performed by running the engine or idling while rotating the steering wheel from side to side.