I know this is an old post but I was wondering if you ever solved this problem? Mine does the exact same thing and the brake pedal is so hard after sitting overnight that I can't push it down, and it won't start unless the brake is depressed and I literally have to force it down hard to start it. The temperature doesn't seem to matter as mine has done it in my warm condo underground. It doesn't appear to be a vacuum problem but more of a brake fluid problem from forcing the brake caliper pistons back when a brake job is done because mine only started doing this after front/ back rotors and pads were replaced. The dealer say's the typical "this is normal" and "you probably never noticed it before" It's my 3rd. Dodge Journey and it's not normal. Is it possible there is air in the brake lines and over time the hydraulic effect of the air slowly pushes the brake pads out while sitting pushing the pads tight against the rotors? or did you find a solution? Thanks in advance.