So my brakes nearly went out coming home from a friend's house yesterday. I pull it into the garage, and see a bunch of brake fluid on the inside of the pass side tire. I pulled the wheel, spacer and brake pad bracket off to find there was no inner pad. The piston on the caliper was acting as the pad, with less than desirable results. Thankfully the parts for these trucks are pretty cheap. $30 for a new caliper, $20 for a new rotor, and $17 for new pads. Now I wonder what the hell happened to the old pad? they weren't very old, still half the friction material left. Just in time for wheelin'. there's an event this weekend, so I gotta get the "Rusty Mongoose" all fixed up by Saturday.
Here's a video from the event last year(should probably be in the adventure section). Look for me at 1:12, and various other places, like getting winched up a steep hill.

2010 MNTrailRiders at River Falls - Fall Run

Yea, pads don't normally fall out like that without some help.  Well, at least you found the problem. 

Did you just replace the one side?

Just the caliper on one side. Pads, and rotor on both sides.

Sounds like one of two thoughts, either the pad was forgotten long ago during a brake job, or the caliper sliders malfunctioned and the inner pad wore thru both the pad material and the steel backing and it then fell out.

I have seen this happen a few times when the wheel bearings get loose.  There is enough deflection on the rotor that the pad slips out.

update: Replaced both calipers since I couldn't get the piston to compress on the driver's side. Fun stuff! The brakes feel a little soft, guess I need to bleed them again.

Guess it was just their time to go.

A good WTF? moment.

Yeh WTF? I just seen a bunch of jeeps!