How to Properly Test Trailer Service Brakes?

What is the correct procedure for testing the trailer service brakes?

A. Push in the red "tractor protection valve" button and apply the trailer handbrake.

B. Pull out the red "tractor protection valve" button and apply the trailer handbrake.

C. Push in the yellow "tractor protection valve" button and apply the trailer handbrake.

D. Pull out the yellow "tractor protection valve" button and apply the trailer handbrake.

Answer:

To test the trailer service brakes, the correct procedure is to pull out the red "tractor protection valve" button and apply the trailer handbrake.

Testing trailer service brakes is an essential part of ensuring safety while on the road. When performing this test, it's crucial to follow the correct procedure to guarantee the brakes are functioning properly.

The correct answer for the air valves when testing the trailer service brakes is B. Pull out the red "tractor protection valve" button and apply the trailer handbrake. This action cuts off the air supply from the tractor to the trailer, allowing the brakes on the trailer to be tested independently.

The "tractor protection valve" is typically a red eight-sided knob located on the dashboard of the tractor. By pulling out this valve, the trailer brakes are activated separately when engaging the trailer handbrake. This step ensures that the trailer brakes are working effectively without relying on the tractor's braking system.

Understanding and following the correct procedure for testing trailer service brakes is crucial for preventing accidents and maintaining control of the trailer. By regularly checking and testing the brakes, drivers can ensure the safety and functionality of the braking system, providing peace of mind while on the road.