Old 40/60 pressure switch would not shut off, notice the breaker switch on wall would be kicked out the next morning. Adjusted #2 nut, that worked for a few days but then again, it would not shut off on it's own. Replaced it with brand new pressure switch, still have same problem, does not shut off on it's own. Any idea what problem could be?

When you replaced the switch, did you check the little pipe it attaches to to make sure it was not clogged?

Are you sure the pressure is getting up high enough to hit the cut out point?