CSLB General Building (B) Trade Practice Test
Preguntas frecuentes
¿Cuántas preguntas de práctica de CDL Air Brakes hay aquí?+
Un banco completo de preguntas originales de CDL Air Brakes en las áreas oficiales, con el peso del examen real y explicaciones. Gratis, sin registro.
¿Cómo es el examen CDL Air Brakes?+
Unas 60 preguntas. Practica por tema aquí y luego haz el simulacro cronometrado para medir tu preparación.
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La práctica de PrepPass está en inglés, 中文 y español. El examen oficial es en inglés — cambia el idioma de las preguntas a inglés para ensayar la terminología del día del examen.
Preguntas de práctica de ejemplo
Algunas preguntas reales de este banco gratuito, con explicaciones completas. Usa la herramienta de arriba para el banco completo.
- 1. System Parts
What is the purpose of the air compressor in an air brake system?
- a.To release the parking brakes automatically
- b.To pump air into the air storage tanks
- c.To warn the driver of low air pressure
- d.To apply the service brakes evenly
Respuesta: b
Explicación: The air compressor pumps air into the storage tanks (reservoirs) that hold the compressed air used for braking. It is usually connected to the engine by gears or a belt. Without it, the system could not build or maintain the air pressure the brakes need to work.
- 2. System Parts
Spring brakes on a truck are held in the released position by what?
- a.Air pressure
- b.Hydraulic fluid
- c.Engine vacuum
- d.Electrical current
Respuesta: a
Explicación: Spring brakes use powerful springs to apply the brakes, and air pressure holds those springs back so the brakes stay released while driving. If air pressure is lost, the springs push the brakes on automatically. This provides an automatic safety braking feature when air is lost.
- 3. System Parts
What does the brake pedal (foot valve) do in an air brake system?
- a.It pumps air into the storage tanks
- b.It drains water from the reservoirs
- c.It controls how much air is sent to apply the brakes
- d.It engages the parking brake springs
Respuesta: c
Explicación: Pressing down on the brake pedal, also called the foot valve or treadle valve, sends air to apply the service brakes. Pressing harder applies more air pressure and more braking. Letting up on the pedal reduces the air pressure and releases the brakes.
- 4. System Parts
Why should the trailer hand valve NOT be used for parking?
- a.Air could leak out and release the trailer brakes
- b.It applies too much braking force to the tractor
- c.It drains the primary air tank
- d.It disables the low-pressure warning
Respuesta: a
Explicación: You should not use the trailer hand valve for parking because the air could leak out and release the trailer brakes over time. The spring-loaded parking brakes should be used instead, since they are held on by springs and do not depend on air pressure. Relying on the hand valve could let the trailer roll.
- 5. Inspection
During a walk-around inspection, how do you check manual slack adjusters on S-cam brakes?
- a.By listening for air leaks at the wheel
- b.By measuring the air pressure at each chamber
- c.By pulling hard on each one and checking that it moves no more than about one inch
- d.By spinning the wheel by hand
Respuesta: c
Explicación: With the parking brakes released and wheels chocked, pull hard on each manual slack adjuster you can reach. If it moves more than about one inch from where the pushrod attaches, it is probably out of adjustment. Brakes that are out of adjustment do not work properly and are unsafe.
- 6. Inspection
How do you perform the static leakage (applied pressure) test on a straight truck with air brakes?
- a.With a fully charged system, release the brakes, turn off the engine, apply full brake pressure, and watch that the drop does not exceed the allowed limit
- b.Drain the tanks and check that they refill on their own
- c.Drive at 20 mph and slam on the brakes
- d.Disconnect the trailer and check the gladhands
Respuesta: a
Explicación: With the air system fully charged (about 125 psi), turn off the engine, release the parking brake, and hold the brake pedal down (fully applied). After the initial pressure drop stabilizes, the air pressure should not drop more than 3 psi in one minute for a straight truck (4 psi for a combination). A greater loss means there is a leak that must be repaired.
- 7. Inspection
During inspection, brake linings (shoes or pads) should be checked for what?
- a.Correct color and shine
- b.Proper air pressure
- c.Excessive wear and to make sure they are not soaked with oil or grease
- d.Frozen water inside them
Respuesta: c
Explicación: Brake shoes or pads should not be worn dangerously thin, and they should be free of oil or grease. Linings that are too thin or contaminated cannot provide enough friction to stop the vehicle. Cracked, broken, or missing linings are also out-of-service conditions.
- 8. Inspection
What is the correct order for the brake system portion of a pre-trip inspection regarding air build-up?
- a.Build pressure to cutout, then test build-up rate, warning signal, spring brake activation, and leak rates
- b.Test the parking brake first, then drain all tanks
- c.Drive the vehicle, then check the compressor
- d.Apply the hand valve, then check the tires
Respuesta: a
Explicación: You first let the system build to governor cutout to confirm the compressor and governor work. Then you check the build-up rate, test the low-pressure warning, continue fanning to confirm the spring brakes apply, and finally check the leak rates. Doing the checks in order confirms each safety feature works.
- 9. Operation & Safety
What is the most important thing to do to control your speed on a long, steep downgrade?
- a.Ride the brakes lightly the whole way down
- b.Shift into neutral and coast
- c.Use a low gear so the engine helps hold the vehicle back
- d.Pump the brakes continuously as fast as possible
Respuesta: c
Explicación: The most important factor on a long downgrade is to select a low gear before starting down, so engine braking helps control your speed. The proper braking technique is then used only to supplement the low gear. Being in the right gear keeps the brakes from overheating and fading.
- 10. Operation & Safety
When stopping normally with a vehicle equipped with air brakes, how should you apply the brakes?
- a.Apply steady, controlled pressure without letting the wheels lock
- b.Slam the pedal to the floor immediately
- c.Pump the pedal rapidly the entire stop
- d.Use only the trailer hand valve
Respuesta: a
Explicación: For a normal stop, push the brake pedal down with controlled, steady pressure to slow smoothly without locking the wheels. Locked wheels can cause a skid and loss of control, especially on vehicles without anti-lock brakes. Smooth, firm application gives the best control.