ASE S4 Brakes Exam Practice Questions and Answers

ASE S4 Brakes Exam Practice Questions and Answers The air system is maintained at what pressure? - Answer️️ -100 to 120 pounds per square inch. At what pressure does the low pressure switch activate? - Answer️️ -Below 60 pounds per square inch. A safety or pop off valve is usually installed in which reservoir? - Answer️️ -In the one closest to the compressor. Why is the Wet tank referred to as such? - Answer️️ -It is the one closest to the compressor and has the most water in it. What is an after cooler used for in an air system? - Answer️️ -It condenses and eliminates most of the water from an air system. What does an air drier do in a air system? - Answer️️ -They usually contain a bed of desiccant material which captures water and oil. What does the dual control foot valve control? - Answer️️ -After the wet tank the valve controls the primary and secondary systems. In a normal operation what does the primary air brake system control? - Answer️️ -The rear axle brakes. In a normal operation what does the secondary air brake system control? - Answer️️ -The front axle brakes. ©SOPHIABENNET@2024/2025 Wednesday, August 21, 2024 12:13 PM 2 What does the two way check valve do in the air brake system? - Answer️️ -It allows dominant pressure to activate the stoplight switch and to release the parking brakes. What is the standard releases of the parking brake system in the event of a failure? - Answer️️ -At least once during a failure of either primary or secondary system pressure. Why are relay valves used in a rear air brake system? - Answer️️ - To minimize delay of brake application on long wheel based applications. What determines the crack pressures on a air brake system relay valve? - Answer️️ -How heavily loaded the axle is. The size of the axle's brakes. Aggressiveness of the linings. What is a quick release valve used for in air brake systems? - Answer️️ -It allows brake actuation air to be quickly exhausted near the brakes it serves. What is the minimum apply time of air brake systems? - Answer️️ -0.45 seconds. What is the minimum release time of air brake systems? - Answer️️ -0.55 seconds. What is a ratio valve in air brake systems? - Answer️️ -Also known as a pressure reducing valve, limits air pressure to the front axle. They have a variety of hold off pressures. ©SOPHIABENNET@2024/2025 Wednesday, August 21, 2024 12:13 PM 3 What is the first step in system diagnosis of air brake systems? - Answer️️ -The driver should be interviewed. If air brake systems are not applying and releasing properly, and grabbing or dragging what could be the cause? - Answer️️ - Defective supply system components. If air brake systems have instability and premature wear what could be the cause? - Answer️️ -As little as a 4 pounds per square inch difference between axles can cause this. If all around braking performance is poor or low air pressure is prevalent what could be the cause? - Answer️️ -Clogged compressor air filter. Slipping belt. Air leaks. Restricted lines. Defective governor. Malfunctioning air compressor. If air system pressure is too high what could be the cause? - Answer️️ -Defective governor. Reservoir safety valve. Gove