310T Air Brake Systems Diagnosis Questions and Answers

Question 1

A technician is diagnosing a truck with a complaint of slow air pressure build-up.
The test shows it takes over three minutes for the pressure to rise from 85 to 100 PSI at governed RPM.
Which of the following is the LEAST likely cause of this issue?

Accepted Answer

A faulty low-pressure warning switch

Answer

A slipping compressor drive belt

Answer

Excessive carbon buildup in the discharge line

Answer

A leaking unloader valve on the compressor

Question 2

During a routine service, a technician observes that the air governor cuts out at 145 PSI and the safety valve releases air. What is the MOST likely cause of this condition?

Accepted Answer

An improperly adjusted or faulty governor

Answer

A leaking air dryer purge valve

Answer

A restricted compressor intake

Answer

A ruptured service brake diaphragm

Question 3

A driver reports that the service brakes on their truck are slow to release, causing a dragging sensation. Which of the following components is MOST likely to cause this specific symptom?

Accepted Answer

A sticking quick-release or relay valve

Answer

A malfunctioning automatic slack adjuster

Answer

A saturated air dryer desiccant cartridge

Answer

A leaking spring brake chamber

Question 4

When performing an applied air loss test, a technician chocks the wheels, releases the spring brakes, and applies firm pressure to the service brake pedal with the engine off. What is the maximum allowable pressure drop for a straight truck in one minute after the initial pressure drop?

Accepted Answer

3 PSI

Answer

1 PSI

Answer

2 PSI

Answer

4 PSI

Question 5

A coach is brought in with the complaint that the spring parking brakes will not release. The air system builds to the correct cut-out pressure, and there are no audible leaks. Which of the following is a plausible cause for this failure?

Accepted Answer

A malfunctioning inversion valve

Answer

A failed service brake relay valve

Answer

A clogged air dryer filter

Answer

Excessive slack adjuster free play

Question 6

A technician is diagnosing a vehicle that pulls to the left only when the service brakes are applied. The foundation brake components and tire pressures are confirmed to be good. Which of the following is the MOST likely cause?

Accepted Answer

A restricted air line to the right side brake chambers

Answer

A seized S-cam roller on the right side

Answer

A faulty automatic slack adjuster on the left side

Answer

A leaking diaphragm in the left side brake chamber

A technician is diagnosing a truck with a complaint of slow air pressure build-up.The test shows it takes over three minutes for the pressure to rise from 85 to 100 PSI at governed RPM.Which of the following is the LEAST likely cause of this issue?

A technician is diagnosing a truck with a complaint of slow air pressure build-up.
The test shows it takes over three minutes for the pressure to rise from 85 to 100 PSI at governed RPM.
Which of the following is the LEAST likely cause of this issue?