I have a 2008 Edge FWD that sat for a month while awaiting parts for the airbag recall. While taking it to the dealership to get fixed, I noticed the brakes were a bit mushy/spongy and had a "metal scraping feel to it" before the pedal recovered to normal press. I took the front DR caliper off (to start) and I notice the rubber sleeve for the lower caliper bolt was dry rotted and came apart when removing the bolt. I replaced the boot (loaded with grease) all the metal clips (the hardware kit came with all) and put everything back thinking that was the issue. Took off down the road and by about mile 1-2, same thing again....mushy/spongy metal grab feel then the pedal comes back to normal level. I wanted to rule out air in the lines, so I bled all 4 calipers and took off down the road and again, at about 1-2 miles same thing all the sudden. I came home and loosened the caliper bolts and noticed that this time, the calipers didn't need compressing to remove (both front calipers) as I was able to remove with a very little effort.
At this point my options are master cylinder (most likely by the symptoms) or the brake booster. They are both a pain to get off, even more if its the brake booster as I have to pull the master cylinder, wiper arm and a several other brackets off. Has anyone else ever ran across this and may have a solution as I am out of straws to pull.