HEAVY TRUCK BRAKES MICHIGAN MECHANIC STUDY GUIDE QUESTIONS AND ANSWERS 2025/2026

HEAVY TRUCK BRAKES MICHIGAN MECHANIC STUDY GUIDE QUESTIONS AND ANSWERS 2025/2026 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. 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)