HEAVY TRUCK BRAKES MICHIGAN MECHANIC
LATEST EXAMS SCRIPT QUESTIONS AND
ANSWERS RATED A+
✔✔the air charges the trailer reservoir is supplied from the main reservoir to: - ✔✔a.
part a, to part d, to the foot valve, to part e, to part c, then through gladhand 2 to part b.
b. the foot valve, to part d, to part c, then through gladhand 2 to part b.
c. valve e, to part c, to part b.
d. part a, to part d, to part c, then throygh gladhand 1 to part b. (not correct awnser)
✔✔with the air brakes in the applied position on a tractor trailer, what is an acceptable
air pressure loss in the system? - ✔✔a. the pressure should not drop at all in period of
one minute. (not correct awnser)
b. 25 psi/minute.
c. 15 psi/minute.
d. 4 psi/minute. (possible correct awnser)
✔✔approximately what air pressure will be required on a fail safeor spring brake style
parking brake to hold off the spring brakes? - ✔✔a. 120-150 psi.
b. 10 psi-15 psi.
c. 60 psi-80 psi. (correct awnser)
d. 5 psi.
✔✔the air pressure in the system is below normal, what is the most liekly cause: - ✔✔a.
a frozen two-way check valve.
b. a plugged safety valve.
c. a defective compressor govenor. (possible correct awnser)
d. all of the above. (not correct awnser)
✔✔in an "s" cam brake, the chamber push rod is returned to its released position by: -
✔✔a. the brake chamber diaphragm.
b. the brake slack adjusters.
, c. a spring in the brake chamber. (correct awnser)
d. air pressure.
✔✔a pulsating brake pedal in a hydraulic ststem can be caused by: - ✔✔a. an out-of-
round drum. (correct awnser)
b. a defective master cylinder.
c. a defective combination valve.
d. a bad vacuum booster.
✔✔the emergency brake line on most trailers is installed: - ✔✔a. without gladhands.
b. as two lines, one on each side of the trailer. (not correct awnser)
c. on the driver side or left side. (possible correct awnser)
d. on the curb or right side.
✔✔ an engine brake (jacobs brake) - ✔✔a. is a self-energizing servo type.
b. is normally used in place of a spring brake.
c. restricts the intake port and causes a build up of 30-45 lbs of pressure.
d. opens the exhaust valves near the top of the compression stroke to release the
compressed air. (correct awnser)
✔✔in the system shown below, the part at c is: - ✔✔a. an inversion valve. (possible
correct awnser)
b. a safety valve.
c. a modulator valve. (not correct awnser)
d. a relay valve.
✔✔a mechanic has removed a brake drum and found the brake linings soaked with
grease. the brake linings should be: - ✔✔a. replaced. (correct awnser)
b. sanded to roughen up the friction surface.
c. dipped in lacquer thinner.
d. washed with denatured alcohol.
✔✔in the drawing below, the parking brakes are applied by: - ✔✔a. air pressure at point
f.
b. vacuum in area b.
c. spring at point c.
d. pressure in area a. (not correct awnser)
✔✔what is the purpose of a vacuum booster? - ✔✔a. to decrease brake pedal effort.
(possible correct awnser)
b. to prevent fade under heavy braking.
c. to provide assistance when the engine vacuum is low. (not correct awnser)
d. to maintain uniform pedal travel as the linings wear.
LATEST EXAMS SCRIPT QUESTIONS AND
ANSWERS RATED A+
✔✔the air charges the trailer reservoir is supplied from the main reservoir to: - ✔✔a.
part a, to part d, to the foot valve, to part e, to part c, then through gladhand 2 to part b.
b. the foot valve, to part d, to part c, then through gladhand 2 to part b.
c. valve e, to part c, to part b.
d. part a, to part d, to part c, then throygh gladhand 1 to part b. (not correct awnser)
✔✔with the air brakes in the applied position on a tractor trailer, what is an acceptable
air pressure loss in the system? - ✔✔a. the pressure should not drop at all in period of
one minute. (not correct awnser)
b. 25 psi/minute.
c. 15 psi/minute.
d. 4 psi/minute. (possible correct awnser)
✔✔approximately what air pressure will be required on a fail safeor spring brake style
parking brake to hold off the spring brakes? - ✔✔a. 120-150 psi.
b. 10 psi-15 psi.
c. 60 psi-80 psi. (correct awnser)
d. 5 psi.
✔✔the air pressure in the system is below normal, what is the most liekly cause: - ✔✔a.
a frozen two-way check valve.
b. a plugged safety valve.
c. a defective compressor govenor. (possible correct awnser)
d. all of the above. (not correct awnser)
✔✔in an "s" cam brake, the chamber push rod is returned to its released position by: -
✔✔a. the brake chamber diaphragm.
b. the brake slack adjusters.
, c. a spring in the brake chamber. (correct awnser)
d. air pressure.
✔✔a pulsating brake pedal in a hydraulic ststem can be caused by: - ✔✔a. an out-of-
round drum. (correct awnser)
b. a defective master cylinder.
c. a defective combination valve.
d. a bad vacuum booster.
✔✔the emergency brake line on most trailers is installed: - ✔✔a. without gladhands.
b. as two lines, one on each side of the trailer. (not correct awnser)
c. on the driver side or left side. (possible correct awnser)
d. on the curb or right side.
✔✔ an engine brake (jacobs brake) - ✔✔a. is a self-energizing servo type.
b. is normally used in place of a spring brake.
c. restricts the intake port and causes a build up of 30-45 lbs of pressure.
d. opens the exhaust valves near the top of the compression stroke to release the
compressed air. (correct awnser)
✔✔in the system shown below, the part at c is: - ✔✔a. an inversion valve. (possible
correct awnser)
b. a safety valve.
c. a modulator valve. (not correct awnser)
d. a relay valve.
✔✔a mechanic has removed a brake drum and found the brake linings soaked with
grease. the brake linings should be: - ✔✔a. replaced. (correct awnser)
b. sanded to roughen up the friction surface.
c. dipped in lacquer thinner.
d. washed with denatured alcohol.
✔✔in the drawing below, the parking brakes are applied by: - ✔✔a. air pressure at point
f.
b. vacuum in area b.
c. spring at point c.
d. pressure in area a. (not correct awnser)
✔✔what is the purpose of a vacuum booster? - ✔✔a. to decrease brake pedal effort.
(possible correct awnser)
b. to prevent fade under heavy braking.
c. to provide assistance when the engine vacuum is low. (not correct awnser)
d. to maintain uniform pedal travel as the linings wear.
