The only thing I can suggest is to hammer the heads of the bolts -sideways-. This helps to break free the 'rust bond'. Be careful to hit against one or another of the hex flats, so as to not mess up the hex. Of course you should be using only 6 point wrenches, not 12 point.
If you have access to an impact gun (My experience is that the air driven types are stronger than the electric or cordless ones I have seen working), try using it each day, after soaking with pb blaster (a couple of times a day), and be sure to use the impact gun in BOTH directions: A few seconds 'turning right', then a few seconds 'turning left', etc.
Your problem makes me want to get under my Escort and loosen up the bolts under there, and grease the threads, then re-torque.