Jamar hand brakes

[Keith Wenzel]

I have the Jamar hand brake for the rear tires (makes sense, I know) and for some reason, they don't lock up the tires like I think they should. Overall, the brakes work good when pressed by the pedal. When you engage the handle, it doesn't seem to grasp the tires or feel tight.

Is there something special to do when bleeding the rear or other suggestions.