If you're still having this problem, have you gotten out of the car and put your hand over each wheel while the problem is happening to see if one is much warmer than the other? I don't know much about late models and what all of the other system components are, but that sounds like a high quote. If one caliper is locking up, replace that one. You'll have to replace the pads on that end of the car, both sides, to make things even, and probably have those two rotors resurfaced and maybe new brake fluid but that should be it.
Nice Comet, '65Comet! I had early Falcons for years.