Surge Brake question...

Last winter I redid my trailer.. I install all new brake plates and stainless lines. I removed and visually inspected my actuator. I bled the system and am confident I got all the air out.. So here is the question what is making the brakes drag. It seems the actuator is not releasing the pressure created by braking. I have to pull over and release the pressure to get home. It worked well the first few times out but, every time since it has given me trouble.

Any ideas? I don't want to just start swapping parts blindly.

Thanks in advance for any knowledge based suggestion.

Are they drums or discs?

The drum brake actuator/master cylinder has a residual valve that keeps a certain 'preload' on the drum brake cylinder.

So if you had drums and went to discs, then it has to be removed. Or if you already had discs and replaced the master cylinder, make sure you got a master cylinder for discs, or again remove the residual valve.

Could also be you have some junk in the master cylinder bore, and the plunger is not returning completely when the surge coupler moves forward. Typically the surge coupler only pushes on the master cylinder, they aren't directly connected. The master cylinder relies on an internal spring to return the plunger when the coupler releases pressure. I had one rust and it was stuck in.

It is drum. The info about the plunger is what I was seeking. I had no idea whether there was something like that in the system...

Thank You..

Not sure if this will help Jim, but here is a PDF of the coupling used in my trailer. http://www.titan-intl.com/media/model10ii.pdf