My garage door when fully closed has a gap approx. 1/4 - 1/2 in on one side. I recently replaced the weather-striping and the gap is still there. I adjusted the springs on the door. The gap will disappear but only after the springs are adjusted to the point where the door will no longer lift. The best adjustment I can get is the small gap on one side. Any advise on where to start, the door mechanism itself or the slab?