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ASE Transit Bus

H4 Transit Bus — Brakes — practice test

Studying for H4 (Transit Bus — Brakes)? Overhaul Prep has 172 verified H4 questions written to the current task list — in the same formats the real exam uses (direct, Technician A/B, EXCEPT and most-likely-cause). Every answer comes with a written explanation, so you learn why instead of memorising a letter.

172H4 questions
100%with explanations
9,711questions in total
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Sample H4 questions

Straight from the bank — answers highlighted, with the explanation underneath.

What controls the loading and unloading of the air compressor to maintain system pressure within a preset range?

  1. The governor
  2. The safety relief valve
  3. The air dryer purge valve
  4. The treadle valve
WhyThe governor senses reservoir pressure and cycles the compressor between loaded (pumping) at cut-in and unloaded at cut-out, keeping supply pressure in the set range of roughly 100-125 psi.

Two technicians discuss the low-air warning. Technician A says the warning light and buzzer should activate at about 60 psi. Technician B says a driver may safely keep driving once the warning stops as pressure builds, even if the compressor cannot maintain pressure. Who is correct?

  1. Technician A only
  2. Technician B only
  3. Both Technicians A and B
  4. Neither Technician
WhyThe warning must come on by 60 psi, so A is right. B is wrong: if the compressor cannot keep pressure up, the bus must be taken out of service, because ignoring a recurring warning risks total loss of braking.

A bus pulls sharply to the right during braking. The MOST likely cause is:

  1. Grease-contaminated or out-of-adjustment brakes on one side
  2. Low tire pressure in all tires equally
  3. A weak low-air warning buzzer
  4. A saturated air dryer desiccant
WhyUneven braking force side to side, from contaminated linings or mismatched adjustment, produces a directional pull during braking.

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