Changed pads (front) on my TJ. This is a job I have done many times and even did pads on the same car 2 years ago. Fitted bendix GCT, db1203 same as last time. Each pad has 2 metal backing plates. The strange thing is once I had removed both old pads from the RHS front caliper, I noticed a metal piece (H shape, about 65 mm high, 35mm across with the horizontal bar 15 mm up from the bottom). It is thin metal (rusty), same thickness as the backing plates. I have no idea where it came from or what it is. Anyone got any ideas?? I am pretty sure it did not come from the box contaning the new pads. Garage floor was clean before I started working. It was lying on garage floor within 12 inches of the area under the front hub.

Could you post up a photo of the part?

it sits at the front of the pads...ie...in the middle of the caliper..i have no idea what it does..to put it back,you have to take the caliper off again and it locates/sit it in the miidle of the caliper....if this makes sense....

Sounds like an anti-squeal plate.
Sits between the piston and the back of the brake pad.
Usually has small tabs that clip onto the back of the pad.