Question

You have a major leak in the service line, and you apply the brakes. Service air pressure will escape and cause the

1. trailer tank pressure to be lost
2. trailer emergency brakes to come on
3. tractor spring brakes to lock on

Answer 1

A major service line leak in a truck's air brake system can result in the loss of trailer tank pressure, the activation of trailer emergency brakes, and potential engagement of the tractor spring brakes if the pressure drops sufficiently.

Step-by-step explanation:

When you have a major leak in the service line of a truck's air brake system and apply the brakes, the service air pressure will escape. This loss of air pressure can cause several events to occur:

1. The trailer tank pressure may be lost, affecting its ability to brake.
2. The trailer emergency brakes could activate because they are designed to engage when there is a loss of air pressure to ensure safety.
3. However, the tractor spring brakes may not necessarily lock on immediately due to the leak, but if the air pressure drops below a certain level, they could also engage as part of the emergency/parking brake system.

Brakes operate efficiently when the air is properly compressed. If there's air in the brake lines, it must be bled out for the brakes to function correctly, due to air's compressibility and the principles of the mechanical equivalent of heat, as exemplified in Figure 14.5 where smoking brakes on a truck demonstrate heat generation from mechanical action.