So yesterday was fun....middle of a snowstorm, I had an emergency call for work. As I was heading down my street headed towards a very busy arterial, I stomped the brake pedal, hoping to gauge how easy the tires would break traction. Much to my surprise, the pedal dropped all the way to the floor. In conjunction with a few expletives, I slammed the shifter to 1, killed the engine, and hit the parking brake. Stopped with a foot to spare and still clean shorts. Now I had had a front brake pad fail the night before ( Lost most of the pad material ) and was planning on doing the front brakes after the weather cleared. I assumed I had dropped the remains of the pad and popped out the caliper. I limped it a couple blocks back home using the parking brake, borrowed my Dad's pickup, and went on about the day. Later in the evening, I hopped in the Bronco to pull it forward making more room in the driveway, and much to my surprise, the pedal felt perfectly normal. An inspection of the reservoir showed it still had fluid, and no puddles underneath. I'm now leaning towards a master cylinder failure....maybe I hit it with enough force to invert one of the cups briefly. Anyone have any suggestions ? I'm not really in a position to randomly throw parts at it.

Thanks !!

-Scott

 

Cold weather....maybe a cup or seal is real stiff and the cold and sudden pressure was to much. Did you try slamming them as hard as you did the first time?

Also...possible snow packed...

 

No I did not...however, daylight inspection reveals that I did indeed drop part of the pad and with the piston almost fully extended, the fluid level was extremely low. On the reassembly side now...