how to test tractor protection valve

The tractor protection valve is an essential component of a tractor-trailer system. It is responsible for protecting the tractor from the trailer in case of a separation, which can occur due to various reasons such as brake failure or improper coupling. Therefore, it is crucial to ensure that the tractor protection valve is working correctly before using the tractor-trailer on the road. In this article, we will go through the steps required to test the tractor protection valve.

Step 1 - Inspect the Valve

Before proceeding with any testing, the tractor protection valve must be inspected thoroughly for any signs of damage or wear and tear. Check for any visible cracks, leaks, or corrosion on the valve body and fittings. If there are any signs of damage, the valve must be replaced before testing. It is also advisable to check the air lines and fittings connected to the valve for any leaks or damages.

Step 2 - Set up the Testing Equipment

The testing equipment required for testing the tractor protection valve includes a pressure gauge, an air supply, and a manual control valve. Connect the pressure gauge to an air supply with a regulator and set the pressure to 90 psi. Connect the control valve to the tractor protection valve using air lines and fittings.

Step 3 - Test the Valve

Start the testing by closing the tractor protection valve manually using the control valve. Once the valve is closed, the pressure gauge should show a pressure drop of no more than three psi in one minute. If the pressure drop is higher, it indicates a leak in the valve or the connected air lines, which must be fixed before use.Next, open the tractor protection valve and apply 90 psi to it using the control valve. Check the pressure gauge to ensure that the valve opens and remains open at 60 psi and above. If the valve fails to open or close correctly, it indicates a malfunction or damage to the valve, and it must be replaced.

Step 4 - Perform Emergency Brake Test

The final step in testing the tractor protection valve is to perform an emergency brake test. Start by applying the service brakes and releasing them to build up 90 psi in the tractor protection valve system. Next, close the manual control valve and simulate a separation between the tractor and the trailer by disconnecting the air hoses. Once the pressure in the system drops below 20 psi, the tractor protection valve should close and apply the emergency brakes to the tractor. If the emergency brakes fail to engage, it indicates a problem with the valve that must be addressed before using the tractor-trailer system.

Conclusion

Testing the tractor protection valve is essential for ensuring the safety of the tractor-trailer system. By following the steps outlined in this article, one can ensure that the valve functions correctly and offers the necessary protection against a trailer separation. Regular testing and maintenance of the valve can go a long way in preventing accidents and ensuring safe operations of the tractor-trailer system.