Ok, so I'm new to U-Brakes and have kind of got the jist of them but I re-fitted the U-brake to my frame last night and one side is slightly springy and springs away from the rim like it should while the other side has no spring at all. I'm guessing the springs are internal and that the large nut with two flat sides has something to do with it but I'm only guessing.
I'm such a novice, never have any luck with brakes, think I'm gonna resort to carrying a large stick around with me that I can jam in the spokes when I want to stop!!!