To test the proper function of the tractor protection valve, follow these steps:

1. Verify that the system is at ____ pressure.
2. Charge the trailer by opening the _ __ valve.
3. Make a brake application and _ it (use a hand brake valve if ).
4. Disconnect the _ () line (there will be a loss of air).
5. Now disconnect the _ (____) line.

Control (service) air will stop _ and supply (emergency) air should continue to be , depending on the system.

Reconnect the supply (emergency) line and again service air will be . This tests the proper opening and closing operation of the _ portion of the valve. A tractor protection valve with a broken _ _ will not close the valve and will cause a loss of air during normal brake applications if operating the tractor without a ____.

To test the proper function of a tractor protection valve, follow specific steps to verify pressure and test the opening and closing operation of the valve's control portion.

Explanation:

To test the proper function of the tractor protection valve, you need to follow these steps:

Verify that the system is at proper pressure.
Charge the trailer by opening the supply emergency valve.
Make a brake application and release it.
Disconnect the control line. There will be a loss of air.
Now disconnect the supply line. Control (service) air will stop flowing, and supply (emergency) air should continue to be supplied, depending on the system.
Reconnect the supply line, and again, service air will be supplied. This tests the proper opening and closing operation of the control portion of the valve.

A tractor protection valve with a broken control line will not close the valve and will cause a loss of air during normal brake applications if operating the tractor without a trailer.