Brake caliper repair on 300 SDL right rear

[werminghausen]

Sorry...This is my 300SDL! My fault.

I have ordered the ATE repair kit and new rubber hose for my rear brake because I believe one piston is stuck. I have squeeking noises once in a while, sometimes in curves and I hope to resolve these.
I am confident that I can do this job. I am just not sure how to handle the open system.
I need to disconnect the caliper from the hydraulic line for a while and also need to replace the rubber line.

How would you do this part if you don't want to empty the system? I have replaced all brake fluid last fall.
I could cut the old rubber line and plug it with a sheetmetal screw or such, do the repair on the caliper but then how would you change the rubber line without spilling a lot of brake fluid which is a mess?

Is there a way to do the exercise without draining the system?