Need info on loose 74 caliper

The calipers are not mounted rigidly. They must be able to slide as the pads wear. Since the piston only advances from the rear, if the caliper were mounted rigidly, the rear pad would burn up quickly. They do have rubber bushings and or o rings that are supposed to keep them from floppin around. Maybe those are missin. You need to use something like Permatex Anti Seize Compound. It is resistant to very high temperatures. Some pics might help so we could confirm there's nothin else goin on.