HEAVY TRUCK BRAKES MICHIGAN
MECHANIC STUDY GUIDE 2026 QUESTIONS
AND ANSWERS GRADED A+
⩥ IN THE SYSTEM SHOWN BELOW, THE PART AT C IS:. Answer:
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:. Answer: 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:. Answer: 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?. Answer: 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.
⩥ THE TRAILER BRAKES DO NOT WORK. THE TRACTOR
SYSTEM IS AT NORMAL PRESSURE. THERE ARE NO LEAKS
AND THE SERVICE AND EMERGENCY LINES ARE HOOKED UP
RIGHT. WHAT COULD CAUSE THIS PROBLEM?. Answer: A. ICE
IN THE LINES AT THE TRAILER.
B. A BAD RELAY VALVE.
C. A BAD SAFETY RELIEF VALVE.
D. BOTH A AND B. (CORRECT AWNSER)
⩥ THE RESIDUAL VALVE IN THE MASTER CYLINDER:. Answer:
A. LIMITS PRESSURE BUILD UP IN THE SYSTEM.
B. STOPS THE FLOW TO DAMAGED BRAKE LINES.
C. KEEPS SOME PRESSURE IN THE SYTEM WHEN THE BRAKES
ARE RELEASED. (CORRECT AWNSER)
D. IS OPERATED BY ENGINE VACUUM.
, ⩥ HIGHER THAN NORMAL AIR PRESSURE WOULD LIKELY BE
CAUSED BY:. Answer: A. A GOVENOR THAT IS BAD OR OUT OF
ADJUSTMENT. (POSSIBLE CORRECT AWNSER)
B. A PLUGGED SAFETY VALVE. (NOT CORRECT AWNSER)
C. A ONE-WAY CHECK VALVE STUCK OPEN.
D. A STICKY QUICK RELEASE VALVE.
⩥ IF GLADHAND 2 IS UNHOOKED OR HAS A SEVERE LEAK,
WHAT WILL HAPPEN DURING OPERATION?. Answer: A. VALVE
AT A WILL PROTECT THE PRESSURE IN THE DRY TANK.
B. TRACTOR BRAKES WILL APPLY AUTOMATICALLY. (NOT
CORRECT AWNSER)
C. VALVE AT C WILL APPLY TRAILER BRAKES.
D. VALVE AT B WILL APPLY TRAILER BRAKES.
⩥ DURING A HARD STOP, ONE BRAKE HAS LOCKED ON A
TRAILER WITH "S" CAM BRAKES. THE SERVICE AND
EMERGENCY LINES ARE HOOKED UP PROPERLY AND THE
SYSTEM IS AT NORMAL PRESSURE BUT THE BRAKES WILL
NOT RELEASE. WHAT IS THE LIKELY CAUSE OF THIS
PROBLEM?. Answer: A. THE SERVICE BRAKE CHAMBER
DIAPHRAGM HAS SPLIT. (POSSIBLE CORRECT AWNSER)
B. THE CAM HAS ROLLED OVER DUE TO TOO MUCH LINING
WEAR.
MECHANIC STUDY GUIDE 2026 QUESTIONS
AND ANSWERS GRADED A+
⩥ IN THE SYSTEM SHOWN BELOW, THE PART AT C IS:. Answer:
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:. Answer: 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:. Answer: 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?. Answer: 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.
⩥ THE TRAILER BRAKES DO NOT WORK. THE TRACTOR
SYSTEM IS AT NORMAL PRESSURE. THERE ARE NO LEAKS
AND THE SERVICE AND EMERGENCY LINES ARE HOOKED UP
RIGHT. WHAT COULD CAUSE THIS PROBLEM?. Answer: A. ICE
IN THE LINES AT THE TRAILER.
B. A BAD RELAY VALVE.
C. A BAD SAFETY RELIEF VALVE.
D. BOTH A AND B. (CORRECT AWNSER)
⩥ THE RESIDUAL VALVE IN THE MASTER CYLINDER:. Answer:
A. LIMITS PRESSURE BUILD UP IN THE SYSTEM.
B. STOPS THE FLOW TO DAMAGED BRAKE LINES.
C. KEEPS SOME PRESSURE IN THE SYTEM WHEN THE BRAKES
ARE RELEASED. (CORRECT AWNSER)
D. IS OPERATED BY ENGINE VACUUM.
, ⩥ HIGHER THAN NORMAL AIR PRESSURE WOULD LIKELY BE
CAUSED BY:. Answer: A. A GOVENOR THAT IS BAD OR OUT OF
ADJUSTMENT. (POSSIBLE CORRECT AWNSER)
B. A PLUGGED SAFETY VALVE. (NOT CORRECT AWNSER)
C. A ONE-WAY CHECK VALVE STUCK OPEN.
D. A STICKY QUICK RELEASE VALVE.
⩥ IF GLADHAND 2 IS UNHOOKED OR HAS A SEVERE LEAK,
WHAT WILL HAPPEN DURING OPERATION?. Answer: A. VALVE
AT A WILL PROTECT THE PRESSURE IN THE DRY TANK.
B. TRACTOR BRAKES WILL APPLY AUTOMATICALLY. (NOT
CORRECT AWNSER)
C. VALVE AT C WILL APPLY TRAILER BRAKES.
D. VALVE AT B WILL APPLY TRAILER BRAKES.
⩥ DURING A HARD STOP, ONE BRAKE HAS LOCKED ON A
TRAILER WITH "S" CAM BRAKES. THE SERVICE AND
EMERGENCY LINES ARE HOOKED UP PROPERLY AND THE
SYSTEM IS AT NORMAL PRESSURE BUT THE BRAKES WILL
NOT RELEASE. WHAT IS THE LIKELY CAUSE OF THIS
PROBLEM?. Answer: A. THE SERVICE BRAKE CHAMBER
DIAPHRAGM HAS SPLIT. (POSSIBLE CORRECT AWNSER)
B. THE CAM HAS ROLLED OVER DUE TO TOO MUCH LINING
WEAR.
