Just started driving my 1970 440-4BBL Challenger and discovered I have a rear drum brake issue. The brakes worked fine for about 8-10 miles, then I noticed the engine was laboring when I was pulling into my driveway. I barely made it to the garage door when the rear drums locked up. I could smell brake lining material, and check the rear drum temps with an infrared lazer gun and one drum was 290 degrees and the other was 310 degrees.
I figured is was an adjuster issue and let the car sit overnight. The next morning, I was able to roll the car easily with just the push of my hand. Took it out for another test ride and the problem happened all over again. My guess is that it is a hydraulic issue, and that the brake pressure slowly bleeds off from the wheel cylinders. The car is new to me so I don't have the history but it looks like it has a new Master cyl.