HEAVY TRUCK BRAKES MICHIGAN MECHANIC STUDY GUIDE 2025 UPDATED ACTUAL
EXAM WITH CORRECT SOLUTIONS.
AN ENGINE BRAKE (JACOBS BRAKE) - (answer)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: - (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.
, HEAVY TRUCK BRAKES MICHIGAN MECHANIC STUDY GUIDE 2025 UPDATED ACTUAL
EXAM WITH CORRECT SOLUTIONS.
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)
EXAM WITH CORRECT SOLUTIONS.
AN ENGINE BRAKE (JACOBS BRAKE) - (answer)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: - (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.
, HEAVY TRUCK BRAKES MICHIGAN MECHANIC STUDY GUIDE 2025 UPDATED ACTUAL
EXAM WITH CORRECT SOLUTIONS.
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)
