Again my KLIMA

I'm sorry to bother you again with my climate system...
It now seems more and more likely that the compressor is gone. Since you can get the parts to some good prizes, I would like to know from you whether someone can give me tips on how to install or expand the compressor and which work should be carried out overall?
Would be really great, because I don't want to put that much money in my throat again...

Hope for some advices, as I know it no other way from this community ;-)

So thank you and greetings from Hamburg
Harry