You must always take out both caliper units at once - never just one unit. Before you work, loosen the wheel's lug nuts, lift the vehicle high enough to fit jackstands underneath, and support the vehicle's weight using the jackstands. Then you can take off the wheels. Use the banjo bolt and an adapter to remove the hose, keeping out outside material while stopping brake fluid from escaping. Leave the hose alone when you just need to work on other brake system parts. Unbolt the caliper from its mount, let the caliper go, and take off the steering or rear knuckle bracket if necessary - all by removing the right bolts. Uninstall the parts by following the same steps in reverse order, making sure to tighten all mounting bolts, both on the caliper and any connecting brackets, to their recommended tightened values. Replace the rubber seals on both sides of the brake tube connective piece, then use a torque wrench to make the connection fasten to required strength. Finish your work by bleeding the brake system, putting back the wheels with their lug nuts, letting the car down, then carefully tightening all lug nuts to the needed torque specs.