[bobbader]

The problem is most likely a worn spring perch and/or the perch hole in the axle. If the perch was ever loose and driven that way for a long period, the inward force of the spring arch will start pulling the perch toward the center of the axle. Since the brake actuating shaft is attached to the perch, it moves inward as well, maybe causing the gap you have. As the car moves, with the forces on the spring of steering maneuvers, suspension, and the weight of the engine on the front end, the top of the perch wants to move inward and the bottom wants to move outward. after some time, the perch shaft gets worn and the perch hole in the axle is oblong at top and bottom. In the picture, note the offset between the top of the wishbone yolk and the perch hole boss. While these are not precision fits, there is quite a misalignment in the picture. When this happens, the brake operating pin inside the king pin gets cocked at an angle such that it rubs against the top and bottom bore of the king pin. This can be the reason your brake mechanism moves with some resistance. Tightening the perch nut will not fix the situation. A new perch and having the perch hole bushed may be in your future.