Rear brakes on 2005 Freestar (disk brakes)

About a year ago, I did a complete brake job on my Freestar. I started on the rear brakes about 18 hours before having to leave for a long trip. When I tried to compress the pistons on the rear calipers, they wouldn't compress. I had the tool to turn the piston, but it didn't work. I rushed to a parts house to get new calipers, put everything back together, bled the brakes and everything was fine.

As soon as the brakes started to wear down a bit, I started getting a "clunk" sound when I hit the brakes, coming from the rear. This turned into a rattle, which stopped when I stepped on the brake or pulled up the handbrake a couple of notches.

I took everything apart on the rear brakes and everything seemed to be normal. I replaced the 8 anti-rattle clips and it quieted down for a while. Then the rattle and clunk started again.

Now, a year later, the rattle is getting really bad.

I can reach under the car and move the rear calipers around. Everything is mounted properly and tight. But the pistons seem to be retracting when the brakes are off. It seems like the pressure should release when the brake is off, but not actually retract the piston to the point that the calipers float around 1/4". The brake pads are just sitting in the little mounts on the end and rattling around between the caliper and the brake disk.

I've bled the brakes multiple times, both the normal 2-person way and with a vacuum bleeder.

At this point, I don't know what to try next. Is it possible the calipers are defective? It's happening on the both the right and left sides. Is there something I'm missing here?

Not that there's any similarity, but the rear brakes on an Escort with 4 wheel disc need to be adjusted up until the pads just barely touch the discs. There is an adjustment gear on the back of the caliper that moves the piston back and forth. I think the calipers need to be adjusted. You mentioned that you had bought a tool to do this but you couldn't get the piston in the calpers to retract. Whether or not you have the adjstment on the back side of the caliper or the type of pistons that screw in or screw out, you definately need to tighten up the calipers on the rotors.

Not that there's any similarity, but the rear brakes on an Escort with 4 wheel disc need to be adjusted up until the pads just barely touch the discs. There is an adjustment gear on the back of the caliper that moves the piston back and forth. I think the calipers need to be adjusted. You mentioned that you had bought a tool to do this but you couldn't get the piston in the calpers to retract. Whether or not you have the adjstment on the back side of the caliper or the type of pistons that screw in or screw out, you definately need to tighten up the calipers on the rotors.

Sorry, no adjustment on the calipers. I did get a suggestion that the parking brake activates an adjuster inside the caliper.