Mid term Chapter 30-31
Technician A says that air from the treadle vale is used to apply the rear brake chambers. Technician B says air from the treadle valve is used to apply the front brake chambers. Who is correct?
Both are correct
Technician A says that brake balance can be upset by replacing brakes on one wheel end only. Technician B says that brake balance can be upset by replacing and airline with one of a larger size. Who is correct?
C - Both Technicians are correct
Technician A says that the air dryer purge cycle can last up to 30 seconds. Technician B says that most of the air expelled durning the dryer purge exits the dryer in a couple of seconds. Who is correct?
C - Both Technicians are correct
Technician A says that today's truck air brake systems will usually have two reservoirs: a primary and a secondary. Technician B says that all truck air brake systems today will use an air dryer to remove moisture. Who is correct?
C - Both Technicians are correct
Technician A says that two dash gauges are used to indicate system air pressure. Technician B says that the low air warning system usually activates at approximately 65 Psi (448 Kpa). Who is correct?
C - Both Technicians are correct
Technician A says that when testing for brake leakage, a single axle vehicle with brakes applied should leak no more than 4 psi (28 Kpa) in two minutes. Technician B says that the acceptable leakage for a tractor and one trailer combination is no more than 6 psi (41 kpa) in two minutes. Who is correct?
C - Both Technicians are correct
Technician A says that an air brake system consists of a supply system, a delivery system, and an emergency park brake system. Technician B says that air brake systems have been used in on road vehicles for more than 100 years. Who is correct?
C - Both Technicians are correct.
Technician A says that brake dust no longer contains asbestos, so we don't have to worry about it as much as in the past. Technician B says that brake dust should be vacuumed off the wheel end with a HEPA filter equipped vacuum cleaner. Who is correct?
C - Both are correct
Technician A says that quick release valves are used on the front and rear brakes to speed up the exhaust of actuation air from the chambers. Technician B says that relay valves are used on the rear brake system to speed up the brake application. Who is correct?
C - Both are correct
Technician A says that brake chamber stroke length varies widely and can be as much as 3 inches (7.6cm) on some brake chambers. Technician B says chamber stroke length is unimportant as long as the angle between the slack adjuster and the push rod is 90 degrees or more with the brakes applied. Who is correct?
D - Neither Technician
Technician A says that tractor and straight truck relay valves can be interchanged on a vehicle without affecting braking. Technician B says that an elbow installed on a relay valve control port can affect brake timing. Who is correct?
D - Neither are correct
Technician A says that all compressors pass some oil to the vehicle air system. Technician B says that oil passing is nothing to worry about, as it helps lubricate the air brake valves. Who is correct?
Technician A
Technician A says that the primary and secondary reservoirs are used so the system can be divided into two brake circuits: one supplying the front brakes the other supplying the rear brakes. Technician B says the primary reservoir normally delivers to the front brakes and the secondary reservoir delivers to the rear brakes. Who is correct?
Technician A
Technician A says that when looking at the head of an installed s-cam camshaft, if one of the lobes points up on the left hand side, it is a left-hand camshaft. Technician B says that, when looking at the head of an installed s-cam camshaft, if one of the lobes points down on the right hand side, then it is a right-hand camshaft. Who is correct?
Technician A
Technician A says that air dryer desiccant absorbs water from the air. Technician B says when the air dryer purges, extremely dry air rushes over the desiccant to flush the water from its surface. Who is correct?
Technician A is correct
Technician A says that, when replacing a spring brake chamber system, air can be used to cage the brake, and then the caging bolt should be installed hand tight. Technician B says that, for safety, the entire system air should be drained before removing the chamber. Who is correct?
Technician B
Technician A says that a cam-over condition can be caused by a failed automatic slack adjuster. Technician B says that a cam-over condition can cause a seized brake condition where the brakes won't release. Who is correct?
Technician B is correct
Technician A says that air system reservoirs should be drained weekly unless they are equipped with automatic drain valves. Technician B says that, if oil drains from the primary or secondary drain valve, it indicates the dryer cartridge needs to be replaced or the compressor is defective. Who is correct?
Technician B is correct
Technician A says that double check valves are used in the air brake system so that the reservoir with the higher pressure will supply a circuit. Technician B says that the tractor protection valve will close if there is a sudden full air loss in the trailer supply line. Who is correct?
Technician B is correct
Technician A says the primary reservoir provides the air pressure to apply the parking brakes on an air brake system. Technician B says that a trailer can be supplied with air by either the primary or secondary reservoir. Who is correct?
Technician B is correct
