1. Remove the bars or at least slide them aside and degrease the bar center and the stem clamp interior. Use a little rubber cemrnt to act as an anti-creak and tighten them thoroughly. If all else fails, it's time for new bars and a matching removable faceplate stem.

2. If the pedal is spontaneously loosening, the threads in the crank arm are probably shot. Have your LBS confirm this.

4. Older single pivot side pull brakes were notoriously difficult to keep centered and just twisting the entire unit by hand won't do it. Most of them have flats on the pivot bolt that will accept a thin wrench like a cone wrench. Loosen the clamping nut, center the caliper with the wrench and hold it in position while you tighten the nut. You can also center them by using the big return spring as a centering lever but that's more difficult.