Preguntas CDL de Frenos de Aire gratis

Preguntas de ejemplo de este examen

1. Air brakes are really three braking systems. Which list is correct?Los frenos de aire en realidad son tres sistemas. ¿Qué lista es correcta?
   1. Service, hydraulic and parking
   2. Primary, secondary and trailer
   3. Service, parking and emergency
   4. Foot, hand and engine
   Ver respuesta

   Service, parking and emergency

   An air brake setup is made of the service brake, parking brake and emergency brake systems.

   Un sistema de frenos de aire se compone de los frenos de servicio, de estacionamiento y de emergencia.

2. Why must air tanks be drained?¿Por qué se deben drenar los tanques de aire?
   1. To lower the pressure for the governor test
   2. Water and compressor oil collect in them and can cause brake failure
   3. To let the alcohol evaporator refill
   4. To cool the compressor
   Ver respuesta

   Water and compressor oil collect in them and can cause brake failure

   Water and oil collect at the bottom of the tanks. Water can freeze and cause brake failure.

   El agua y el aceite se juntan en el fondo de los tanques. El agua puede congelarse y causar falla de frenos.

3. Pressing and releasing the brake pedal when it is not needed can:Pisar y soltar el pedal sin necesidad puede:
   1. Raise the air pressure
   2. Adjust the slack adjusters
   3. Let air out faster than the compressor can replace it
   4. Cool the brakes
   Ver respuesta

   Let air out faster than the compressor can replace it

   Each release lets air out. Unneeded pumping can drain air faster than the compressor makes it, and the brakes may not work.

   Cada vez que suelta sale aire. Bombear sin necesidad puede vaciar aire más rápido de lo que se repone.

4. A vehicle with a dual air brake system will have:Un vehículo con sistema dual de frenos de aire tendrá:
   1. A supply gauge for each half of the system, or one gauge with two needles
   2. No supply pressure gauge
   3. Only an application pressure gauge
   4. A gauge on the trailer only
   Ver respuesta

   A supply gauge for each half of the system, or one gauge with two needles

   Dual systems have a gauge for each half, or a single gauge with two needles.

   Los sistemas duales tienen un manómetro por mitad o uno con dos agujas.

5. On large buses, low pressure warning devices commonly signal at:En autobuses grandes, las alarmas de baja presión comúnmente se activan a:
   1. 55–60 psi
   2. 80–85 psi
   3. 100–110 psi
   4. 20–45 psi
   Ver respuesta

   80–85 psi

   It is common for large buses to have low-pressure warnings at 80–85 psi.

   Es común que los autobuses grandes tengan la alarma a 80–85 psi.

6. In a dual air system, the low air warning light and buzzer should shut off when pressure in both systems rises above a value set by the maker. That value must be:En un sistema dual, la luz y el zumbador deben apagarse cuando la presión de ambos sistemas pasa un valor del fabricante. Ese valor debe ser:
   1. Less than 20 psi
   2. Exactly 100 psi
   3. Greater than 55 psi
   4. Greater than 150 psi
   Ver respuesta

   Greater than 55 psi

   The shut-off value is set by the manufacturer and must be greater than 55 psi.

   El valor lo fija el fabricante y debe ser mayor de 55 psi.

7. In newer air brake vehicles, the parking brake control is a:En vehículos nuevos, el control del freno de estacionamiento es:
   1. Round red knob you push in to apply
   2. Yellow, diamond-shaped knob you pull out to apply
   3. Blue lever you push down to apply
   4. Green button on the steering wheel
   Ver respuesta

   Yellow, diamond-shaped knob you pull out to apply

   Newer vehicles use a yellow diamond-shaped push-pull knob: pull out to apply, push in to release.

   Los vehículos nuevos usan una perilla amarilla de diamante: se jala para aplicar y se empuja para soltar.

8. Where is the ABS malfunction lamp on a trailer?¿Dónde está la luz de falla del ABS en un remolque?
   1. On the instrument panel of the tractor only
   2. On the right rear corner
   3. Inside the trailer near the doors
   4. On the left side, on the front or rear corner
   Ver respuesta

   On the left side, on the front or rear corner

   Trailers have yellow ABS lamps on the left side, on the front or rear corner.

   Los remolques tienen la luz amarilla de ABS en el lado izquierdo, esquina delantera o trasera.

9. Before checking slack adjusters on S-cam brakes, you should:Antes de revisar los ajustadores en frenos S-cam, usted debe:
   1. Park on level ground, chock the wheels, and release the parking brakes
   2. Set the parking brakes and pump the pedal
   3. Run the engine at fast idle
   4. Drain all air from the tanks
   Ver respuesta

   Park on level ground, chock the wheels, and release the parking brakes

   Chock the wheels on level ground and release the parking brakes so the slack adjusters can move.

   Calce las ruedas en terreno plano y suelte los frenos de estacionamiento para que los ajustadores se muevan.

10. Which brake lining condition is NOT acceptable?¿Qué condición del forro NO es aceptable?
    1. Soaked with oil or grease
    2. Firmly attached
    3. Of normal thickness
    4. Clean and dry
    Ver respuesta

    Soaked with oil or grease

    Linings must not be loose, soaked with oil or grease, or dangerously thin.

    Los forros no deben estar flojos, empapados de aceite o grasa, ni peligrosamente delgados.

11. Static leakage test (brakes released, engine off, fully charged system): the loss rate for a single vehicle should be less than:Prueba de fuga estática (frenos sueltos, motor apagado, sistema lleno): la pérdida en un vehículo sencillo debe ser menor de:
    1. 1 psi in one minute
    2. 2 psi in one minute
    3. 3 psi in one minute
    4. 4 psi in one minute
    Ver respuesta

    2 psi in one minute

    With brakes released, loss should be under 2 psi/min for single vehicles and under 3 psi/min for combinations.

    Con frenos sueltos, menos de 2 psi/min en sencillos y menos de 3 psi/min en combinados.

12. In a dual air system with a failed low air warning, losing air pressure would mainly:En un sistema dual con alarma dañada, perder presión principalmente:
    1. Cause no change at all
    2. Lock all wheels immediately
    3. Increase stopping distance, with only limited braking before the spring brakes come on
    4. Turn on the brake lights
    Ver respuesta

    Increase stopping distance, with only limited braking before the spring brakes come on

    In dual systems, stopping distance increases and only limited braking is possible before the spring brakes apply.

    En sistemas duales aumenta la distancia de frenado y solo hay frenado limitado antes de los frenos de resorte.

13. For the governor-cut-out applied leakage test, the air pressure should be built up to about:Para la prueba de fuga con freno aplicado, la presión debe estar en el corte del gobernador, unos:
    1. 120–140 psi
    2. 55–60 psi
    3. 85–100 psi
    4. 150–175 psi
    Ver respuesta

    120–140 psi

    Build pressure to governor cut-out (120–140 psi) before the applied leakage test.

    Suba la presión al corte del gobernador (120–140 psi) antes de la prueba.

14. Controlled braking means:El frenado controlado significa:
    1. Applying the brakes fully, releasing when wheels lock, and re-applying
    2. Using only the parking brake
    3. Pumping the brakes quickly
    4. Applying the brakes as hard as you can without locking the wheels, with very small steering movements
    Ver respuesta

    Applying the brakes as hard as you can without locking the wheels, with very small steering movements

    Controlled braking: as hard as possible without lockup, small steering moves; release if wheels lock or you must steer more.

    Frenado controlado: lo más fuerte posible sin bloqueo y con giros pequeños; suelte si se bloquean o necesita girar más.

15. Your truck has ABS on only one axle. Compared with no ABS at all, what is true?Su camión tiene ABS solo en un eje. Comparado con no tener ABS, ¿qué es cierto?
    1. It gives no benefit unless every axle has ABS
    2. It lets you brake as hard as you want in any emergency
    3. It still gives you more control while braking
    4. It makes the regular brakes stop working
    Ver respuesta

    It still gives you more control while braking

    Even partial ABS (tractor only, trailer only, or a single axle) still gives you more control during braking. Keep braking normally.

    Incluso un ABS parcial (solo tractor, solo remolque o un solo eje) le da más control al frenar. Siga frenando normalmente.