when braking, I have to depress, release and depress again for the pedal to be firm. vehicle has about 50K miles on it, with no trailering. fluid level has always been in spec
by Visitor in Leesburg, FL on March 30, 2010
It sounds like air is in the brake hydraulic system, have the brakes "bleed", air should not be present in the system. There is a possibility the brake master cylinder is failing. Another less likely but possible reason is if the front wheel bearings are worn play in the whell bearing can "push back the brake pads" giving a soft pedal on first press of the brake pedal and gets firm on second application of the pedal. This would be more noticeable after taking several sharp turns/winding road.
Just had the same problem in my 2006 Explorer and it turned out to be front passenger wheel hub bearings. Replaced it along with rotors and brake pads and runs like new.