Place the replacement caliper over the brake pads and rotor. Make sure you don’t damage the caliper seals or guide pin bushings from the steering knuckle bosses.
Install the guide pin bolts and the brake hose to the caliper. Use new washers with the brake hose’s fitting bolt.
Fill the brake master cylinder with fluid. Connect the brake bleeder valve to a container of fluid with a rubber hose and have another person remove air from the system by using the brake pedal.
Install the wheels back on the van. Attach the lug nuts to half their full torque before lowering the van, then finish tightening them. Set the brake pads. Pump the pedal until it feels firm. Test the brakes out on the road.