Since this is in the Tmaxx forum, I guess it's a T, and they don't have a dial to adjust the brakes. You need to make a mechanical adjustment. The linkage that goes to the brake servo has collars with set screws. You have to adjust it there. Before you start making adjustments, check the trim adjustment on your radio. Turn the trim all the way down to Zero. If you have the trim set to maintain your idle, you need to adjust your idle setting.
Do you have a computer radio? If so, it's just a matter of going to the menu and adjusting your servo travel end points.
The wobble in the spur is not a problem. There seems to be a slight warp in a lot of the Traxxas spurs, but the mesh is the same all the way around. My stock spur was like that, and it lasted me almost 2 years.