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What may be the cause of lack of tightness in the pneumatic braking system applied in buses?

A damage to air valves.
Excessive clearance on brake shoes spreaders/star wheel adjusters.
Worn brake rotors.

Which of the following symptoms may indicate a malfunction of the air compressor of the brake system in the bus?

Audible air hissing in the diaphragm actuator while braking.
Reduced pressure in the pneumatic system.
Sudden increase in pressure in the braking system.

What type of engine oil should you use in diesel engines used in buses?

Any type.
Selected depending on engine temperature.
As specified by the bus manufacturer.

What oil should be used to top up oil in a bus engine?

Oil characterised by significantly higher stickiness than the oil in the engine.
Oil of the same class as the oil in the engine.
Any type of oil.

Which of the following actions should be performed prior to changing a wheel on a bus?

Place chocks under the opposite wheel.
Release the parking brake.
Set the gear to neutral position.

Is it advisable in winter time to pour petrol into the tank of a diesel engine bus?

Yes it is advisable due to the decrease in petrol clogging.
Yes, it the amount of the petrol poured in is not greater than 10% of the tank volume.
No, because it leads to a damage of the power supply system and the engine.

What function in a diesel engine does a glow plug perform?

It makes the start of a cold engine easier.
It heats up the fuel in the tank.
It heats up the cooling liquid.

Which of the following symptoms may indicate a deficiency of fluid in the power steering on the bus?

Squeaking steering wheel column.
Side skidding of the vehicle front during braking.
Louder operation of the power steering pump when maneuvering the steering wheel with the engine on.

Which of the following symptoms most indicates the clutch disc wear?

Clear resistance of the lever when changing gears.
Difficulties in engaging the first or reverse gear.
Abrupt increase in the engine revolutions without an increase in speed during acceleration.

What is the symptom of excessive total clearance in the steering system?

The tendency for an automatic return of the turned wheels to their central position.
The absence of vibrations in the front suspension.
A deterioration in the steerability and stability of the vehicle.

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