HEAVY TRUCK BRAKES MICHIGAN MECHANIC STUDY
GUIDE WITH COMPLETE SOLUTION RATED A+
2025/2026 NEW
AN ENGINE BRAKE (JACOBS BRAKE) - CORRECT ANSWERS 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: - CORRECT ANSWERS 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: - CORRECT ANSWERS 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: - CORRECT ANSWERS 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? - CORRECT ANSWERS 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? - CORRECT ANSWERS 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: - CORRECT ANSWERS 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: - CORRECT ANSWERS 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.
GUIDE WITH COMPLETE SOLUTION RATED A+
2025/2026 NEW
AN ENGINE BRAKE (JACOBS BRAKE) - CORRECT ANSWERS 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: - CORRECT ANSWERS 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: - CORRECT ANSWERS 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: - CORRECT ANSWERS 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? - CORRECT ANSWERS 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? - CORRECT ANSWERS 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: - CORRECT ANSWERS 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: - CORRECT ANSWERS 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.
