Brakes Siezing

[RalphG]

Had a similar problem on the front disks on a square body GM. It was the rubber line swollen inside that prevented the brake fluid from returning when the pedal was released. It took a while for the pressure to drop.
Another time had a similar event on an old early 50s GM pickup. Actually got under it and partially opened a wheel cylinder bleed screw to let out the steaming hot fluid. Its too long ago to recall how we fixed that problem but on the newer truck it was just a matter of new front rubber hoses to fix it.