Kelsey hayes swap done, but..

well, out riding around today and found some of my problem..I noticed the pedal was getting low today and towards the end of the ride, i could hear metal to metal grinding. I was kinda mad because i JUST got through rebuilding this whole front end, including the KH brakes that i installed. Got home and jacked it up and found the 4 allen headed bolts loose that holds the 2 halves of the caliper together and i was about to fall out and had the caliper itself pushing against the rotor! Now, im not normally one to leave bolts loose..are these known to work loose easily by chance? How tight do they need to be?
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