1999 Cougar Brake Peddle Height

During recent cold snap here(zero and below) my brake peddle needed to be depressed 50 to 75% more than usual to activate brakes. Changed master/bled still the same. Mechanic inspected and changed faulty idler-no help. He also checked vacuum manifold and said it is ok. Weather gotten warmer but problem did not improve What’s causing this$

brake peddle needed to be depressed 50 to 75% more than usual to activate brakes…do you mean 50-75% harder or farther travel?

Mechanic inspected and changed faulty idler-no help…you had a brake problem and the mechanic changed an idler? You got ripped off and/or the tech is a moron.

rear discs or shoes? Sounds like either the rear wheel cylinders blew out , the master cylinder is biting it or the power brake booster is going out. does it stop good still. Could it be air in the lines somehow. Maybe your brakes are just about gone and you have to push the pedal further

Disc all around. New pads all around. New master cylinder. Bled lines twice and bench bled the master before installing. Had the vacuum manifold checked and it is OK. If the booster was going would it not become harder to depress the peddle as the booster helps ease the force neede to depress? I know once I find out what this is I will feel like an idiot.