[Mark44]

Have you looked at the calipers and rotors? They are the components that got hot, so they would be the first things to look at. I would get the car up in the air and see which wheels are affected. If the brakes got very hot, as you said, it can affect the calipers.

Also, if the brake fluid hasn't been regularly purged, it's possible that one or more of the pistons in the calipers is gummed up or corroded (due to water in the brake fluid) and not returning to its rest position.

You mentioned changing two brake boosters. As far as I'm aware, there's only one on your car.