Trailer Hand Brake vs Trailer Brakes
 

Hi,

Whenever I apply the trailer hand brake on my Volvo, the trailer brakes lock up. Obviously, this is not good when at highway speed, or any other speed. The service brakes work just fine with the trailer. The trailer brakes will not release until I set the service and emergency brakes again, wait a few seconds, and then release the brakes. I replaced the TPV within the last year; so I'm thinking it may be the trailer hand brake valve itself. I don't think it's the trailer because I've hooked up to a lot of different trailers in the past two weeks, and the exact same thing happens when I use the trailer hand brake. So, I'm not using the trailer hand brake, but I would like to correct the problem. Any suggestions, thoughts, etc.

What are you using the trailer hand brake for??

Let's hope he says " to check brake lights "..

Does the application gauge drop back down to zero psi after the hand valve is released? Could be a blockage in the exhaust port of the hand valve(or a pinched air line connected to it). Try pulling the service glad hand loose to see if the trailer brakes release. You should be able to blow air back into the trailer service line and have it come out exhaust port of the hand valve when it is in the off position.