Vehicle Mechanics, Maintenance and Pre-Trip Checks
This domain covers the daily walk-around, the systems that fail dangerously on a bus, and the paperwork that proves the vehicle is fit to carry passengers. The examiner asks what you check, what reading is acceptable, and what you do when it is not.
Daily walk-around
Check tyres and wheels, lights and indicators, mirrors, wipers and washer, windscreen condition, bodywork and doors, emergency exits and hammers, fire extinguisher, first aid kit, warning triangle and high-visibility vests, and the tachograph and speed limiter (buses are limited to 100 km/h). Record defects and report them; a defect affecting safety means the vehicle does not leave the depot.
Tyres and brakes
Minimum tread depth is 1.6 mm across the central three-quarters of the tread; pressures are set cold and twin tyres must be matched in size and wear. Cuts, bulges and exposed cords are grounds for withdrawal. For air brakes, build pressure until the compressor cuts out, stop the engine and listen for leaks; a steady loss or a low-pressure warning (typically around 5–6 bar) means the vehicle is unroadworthy. Test the parking brake on a slope.
Fluids and mechanical checks
Engine oil, coolant, brake and clutch fluid, power-steering fluid, washer additive and AdBlue. Check belts for cracking and glazing, look for oil or coolant under the vehicle, and confirm the steering has no excessive free play. Test every door and emergency exit from both sides.
Periodic inspection
Buses and coaches are subject to an annual roadworthiness inspection at a ΚΤΕΟ station, more often than cars, and the certificate must be on board.
Worked example
A driver runs the engine for three minutes and the air gauge reads 4.5 bar, with the low-pressure buzzer still sounding. Is this acceptable? No. The system should reach its governed pressure (about 8 bar) and the warning must extinguish before driving. A bus with insufficient air pressure has degraded service braking and cannot be dispatched, whatever the schedule pressure.
Traps
- Checking the tachograph but not the speed limiter.
- Assuming a recent ΚΤΕΟ certificate replaces the daily check.
- Judging tyre pressure when the tyres are hot.