brake pedal weak on 1997 Cadillac Seville SLS

brake pedal goes all the way to the floor what the problem

Asked by for the 1997 Cadillac Seville SLS
Check the fluid level in the reservoir if it is low there is a leak that needs to be attended to. If the level is fine but the pedal is "mushy" look at the color of the brake fluid if it is brown and dark then the master cylinder may have failed due to contaminated brake fluid. brake fluid should be flushed every two years especially in wetter climates as it takes in moisture from the air.