On some vehicles there is a caliper mounting bracket, on others the caliper screws directly to the steering knuckle.
front pushes in with a bar, rear screws in...
you will have to get a brake caliper tool. the rear caliper the center part turn or screws in with this tool
it screws back in....special tool helpful
First you would need to take the tire off of the van.Next remove the two screws on the backside of the caliper that hold it to the rotor. Once that is done you need to compress that caliper so that you can slide it off of the rotor. I've included a video link that will show you the process of going all of this.
Take the caliper and caliper mount off the knuckle and there will be two Phillips screws on the front of the rotor. Take the screws out by using a impact screwdriver or a air hammer. You won't be able to take them out by hand.
there should be a alen screw through the top and bottom of the caliper that bolts the caliper to the spinle mount bracket remove those two alen screws and the caliper will lift off of the disk and then the brake pads can be removed from the caliper.
Youll probably have to drill it out and get a new bolt to mount the caliper with.
You need to remove the wheel, the caliper and the caliper mount. After you do that you can remove the caliper.
Remove the two slider screws that hold it in place.
Normally 2 but it depends on the make vehicle.
You'll need to remove the wheel, the brake pads and the caliper. Once all of that is out of the way, there are rotor retaining screws that need to be removed, either on the studs, or on the axle itself.
If the piston has come out, the caliper will need replaced.